EPA-550/9-74-018
BACKGROUND DOCUMENT
FOR
PROPOSED MEDIUM AND HEAVY TRUCK
NOISE REGULATIONS
OCTOBER 1974
PREPARED BY
U.S. Environmental Protection Agency
Washington, D.C. 20460
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EPA-550/9-74-018
BACKGROUND DOCUMENT
FOR
PROPOSED MEDIUM AND HEAVY TRUCK
NOISE REGULATIONS
OCTOBER 1974
PREPARED BY
U.S. Environmental Protection Agency
Washington, D.C. 20460
This document has been approved for general
availability. It does not constitute a standard,
specification or regulation.
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TABLIO OP CONTENTS
Section
Summary 1
1 PROLOGUE 1-1
Statutory Basis for Action 1-1
Preemption 1-2
2 IDENTIFICATION OF TRUCKS AS A 2-1
MAJOR SOURCE OF NOISE
Legislative Basis 2-1
Priority Basis 2-1
Day-Night Sound Level Basis 2-2
Population Basis 2-2
Product Basis 2-3
3 THE TRUCK INDUSTRY 3-1
Role of Trucks in Domestic 3-1
Transportation Market
Truck Description for General 3-3
Purposes
Truck Classification for Purposes 3-9
of Noise Regulation
Truck Categories Purposes of 3-9
Report Discussion
Distribution of Trucks by 3-10
Categories
Major Truck Users 3-13
Truck Manufacturers 3-13
4 INFORMATION BASE 4-1
Sources Used for Developing 4-1
Information
Baseline New Truck Noise Levels 4-2
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TABLE OF CONTENTS (CONTINUKD)
Section I'a^v
5 AVAILARLIC NOISU AHATHMKNT f»-1
TECHNOLOGY
Component Noise Control 5-1
Engine 5-1
Fan 5-6
Intake 5-11
Exhaust 5-13
Tire Noise 5-14
Total Truck Noise 5-16
Diesel-Fueled Trucks 5-17
Gasoline-Fueled Trucks 5-19
6 HEALTH AND WELFARE
Introduction 6-1
Effect of New Truck Regulation 6-2
on Public Health and Welfare -
"In the Large"
Introduction 6-2
Definition of Leq and Ldn 6-3
Assessment of Impact Due to 6-5
Environmental Noise
Application of Assessment Tech- 6-13
niques to New Truck Regulation
Urban Traffic Case 6-13
Freeway Traffic Case 6-14
11
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TABLE OF CONTENTS (CONTINUED)
Section Page
Effect of New Truck Regulations on Public 6-23
Health and Welfare "In Individual Cases"
Description of Environmental Situations 6-23
Studied
Discussion of Equation Derived for 6-26
Analysis
Results for Environmental Situations 6-30
Studied
7 ECONOMIC CONSEQUENCES OF NOISE 7-1
CONTROL
Introduction 7-1
Cost of Compliance 7-2
Changes in Truck Manufacturing Costs 7-2
Changes in Truck Operating Costs 7-7
Cost of Compliance Testing 7-10
Cost Impacts 7-11
Impact on Truck Manufacturers 7-11
Impacts on Truck Users 7-25
Impacts on Industries Associated With 7-35
Truck Manufacturers
Impact on National Economy 7-38
Transportation and Trucking in the U. S. 7-38
Economy
Impacts on Exports 7-39
Impacts on Imports 7-40
Impacts on Balance of Trade 7-41
Summary 7-41
iii
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TABLE OF CONTENTS (CONTINUED)
Section Page
8 TRUCK ACOUSTIC ENERGY CHANGES 8-1
AND LEAD TIME REQUIREMENTS
Future Changes in Acoustic Energy Levels 8-1
Lead Time Requirements 8-14
9 MEASUREMENT METHODOLOGY 9-1
Introduction 9-1
Low Speed, High Acceleration Test 9-2
Instrumentation 9-2
Test Sites 9-2
Procedures 9-5
Measurements 9-7
General Comments 9-7
References 9-8
Modifications to SAE J366b 9-9
Nature of the Source 9-9
Modifications 9-9
Geometry 9-10
Microphones 9-10
Test Site 9-11
Instrumentation 9-13
Test Site 9-14
Vehicle 9-16
Tires 9-16
Procedure 9-16
General Comments 9-17
iv
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TABLE OF CONTENTS (CONTINUED)
Section Page
MEASUREMENT METHODOLOGY (Cont'd)
Other Test Procedures 9-18
Summary 9-20
APPENDICES
A. Derivation of Situational Model Equations
B. Architectural-Acoustic Description of Activity Site Structures
C. Calculation of the Total Absorption for the Apartment Activity Site
D. Calculation of the Total Transmittance for the Apartment Activity
Site
E. Typical Measured Truck Operation Noise
F. Calculations to Normalize the Low Speed, High Acceleration Truck
Noise Spectrum
G. Calculation of Situational Factors for the Apartment Activity Site
H. Procedure used to Obtain the Truck Noise Levels at 50 Feet Which
Might Preclude Annoyance
I. Detailed Initial Cost Estimates to Quiet Medium and Heavy Duty
Trucks
J. Costs of Operating Quiet Trucks
K. Computation of Equivalent Truck Price Increases
L. Impact of Quieting Options on Truck Volume
M. First Year Operating Costs for Quieted Trucks
N. Impact of Lead Times on Manufacturers of "Noisy" Engines
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SUMMARY
The subjects addressed in this document are intended to provide
background information on various unpertH associated with the develop-
ment of regulations relative to noise emission I'roiti newly niitnul'acl.nr'ed
trucks.
Section 1 - "Prologue" sets forth the legal basis for the regulations
which may be promulgated under the authority of the Noise Control Act
of 1972, the procedure followed in the promulgation of such regulations
and a brief statement relative to preemption of state and local regula-
tions by Federal regulations.
Section 2 - "Identification of Medium and Heavy Duty Trucks as a
Major Source of Noise. " This section addresses the acoustic energy
radiated by medium and heavy duty trucks.
Section 3 - "The Truck Industry." This section presents general
information about the U. S. truck industry. It covers industry statistics
on sales, number of trucks manufactured, financial data on manufac-
turers, weight classification system and other useful descriptive ma-
terial.
Section 4 - "information Base, " provides a synopsis of the sources
of information utilized in the preparation of this document. It also
presents baseline data on noise generated by currently new trucks. The
data are given for both diesel- and gasoline-powered trucks.
Section 5 - "Available Noise Abatement Technology. " In order to
establish regulations restricting truck noise emissions it is necessary
to know how much noise reduction it is presently possible to achieve. Sec-
1
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tion 5 reviews the various components of truck noise: noise radiated
from the engine surface, fan, intake, exhaust and tire noise.
This discussion includes both the noise generation process nn
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from a highway traversed by trucks. Associated with each scenario
is an ambient level appropriate to the particular activity. The passhy
noise produced by each separate truck is considered as an intrusion
and the extent to which it exceeds the ambient is a measure of the
annoyance produced. A nominal increment of 10 dB(A) is employed,
and the noise outputs of trucks which will produce this increment are
computed. The 10 dB(A) increment is arbitrary; however, it is pre-
sented as the level at which severe annoyance begins. The scenarios
are presented in tables which permit ready identification of those cases
which are satsifactory and those which are not when it is assumed that
a truck produces a specified noise level.
Section 7 - "Economic Consequences of Noise Control. " In this
section costs are developed for the basic engineering changes required
to achieve various levels. Changes in costs due to changes in opera-
tional efficiency are also included. Using these data as a basis, the
impacts on truck manufacturers, truck users, and truck associated
industries are evaluated.
Section 8 - "Truck Acoustic Energy Changes and Lead Time Re-
quirements. " In this section the population statistics of trucks are
presented. The number of trucks presently in operation, the rate of
truck retirement, and truck annual mileage are also given. These are
combined to show population distribution of trucks corresponding to
the various standards which could be proposed.
A mileage-weighted acoustic energy level is presented for each of
the various possible regulatory options.
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Lead times required for various equipment modifications are dis-
cussed. The problems and the time required for the industry to solve
them are considered.
Section 9 - "Measurement Methodology. " This section addresses
EPA test procedures which could be associated with new truck regu-
lations.
Section 10 - "Enforcement." Enforcement of new product noise
emission standards applicable to new medium and heavy duty trucks are
discussed through production verification testing of vehicle configura-
tions, assembly line testing using selective enforcement auditing or
continuous testing (sample testing or 100% testing) of production vehi-
cles and in-use compliance requirements. EPA consideration of the
measurement methodology which could be used both for production
verification testing and assembly line vehicle testing is based upon
the SAE J366b test. Additional tests are outlined in this document
for consideration.
Section 11 - "Environmental Effects. " Whenever action is taken
to control one form of environmental pollution, there are possible
spinoff effects on other environmental or natural resource factors.
In this section the single effects of truck noise control on air and water
pollution, solid waste disposal, energy and natural resource con-
sumption, and land use considerations are evaluated.
The discussion indicates that the process of quieting new trucks will
produce no significant adverse environmental effects. It will result
in a modest saving of fuel, however, if it is credited with the benefits
associated with thermostatically controlled fans.
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Finally, this document constitutes an exposition of the studies made
by EPA and its contractors of the many areas associated with the prom-
ulgation of a noise emission regulation for new trucks. An effort has
been made to produce a document covering all the major issues and it
is hoped that it will be found useful.
Throughout the document, there are references to three data collec-
tion points at which technology, cost, and health and welfare data were
collected and evaluated. Interpolations between the points or extrapo-
lation to levels below the points provide information from which deter-
mination can be made as to truck noise emission which technology may
achieve, the levels at which health and welfare criteria may be assessed,
and the costs and economic impacts associated with various levels«
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SECTION ONE
PROLOGUE
Statutory Basis for Action
Through the Noise Control Act of 1972 (86 Stat. 1234), Congress
established a national policy "to promote an environment for all Amer-
icans free from noise that jeopardizes their health and welfare. " In
pursuit of that policy, Congress stated, in Section 2 of the Act, "that,
while primary responsibility for control of noise rests with State and
local governments, Federal action is essential to deal with major noise
sources in commerce, control of which requires national uniformity of
treatment. "As part of that essential Federal action, subsection 5(b)(l)
requires the Administrator, after consultation with appropriate Federal
agencies, to publish a report or series of reports "identifying products
(or classes of products) which in his judgment are major sources of
noise. " Further, section 6 of the Act requires the Administrator to
publish proposed regulations for each product, which is identified or
which is part of a product class identified as a major source of noise,
where in his judgment noise standards are feasible and fall into var-
ious categories of which transportation equipment (including recrea-
tional vehicles and related equipment) is one.
Pursuant to subsection 5(b)(l), the Administrator has published a
report which identifies new medium and heavy duty trucks as a major
source of noise. As required by Section 6, the Administrator shall
prescribe regulations for such trucks, which are "requisite to protect
the public health and welfare, taking into account the magnitude and
conditions of use of new medium and heavy duty trucks, the degree of
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noise reduction achievable through the application of the best available
technology, and the cost of compliance. "
Preemption
Under subsection 6(e)(l)of the Noise Control Act, after the effective
date'ofa regulation under Section 6 of noise emissions from a new prod-
uct, no State or political subdivision thereof may adopt or enforce any
law or regulation which sets a limit of noise emissions from such new
product, or components of such new product, which is not identical to
the standard prescribed by the Federal regulation. Subsection 6(e)(2),
however, provides that nothing in Section 6 precludes or denies the
right of any State or political subdivision thereof to establish and en-
force controls on environmental noise (or one or more sources thereof)
r
through the licensing, regulation or restriction of the use, operation
or movement of any product or combination or products.
The noise controls which are reserved to State and local authority
by subsection 6(e)(2) include, but are not limited to, the following:
1. Controls on the manner of operation of products
2. Controls on the time in which products may be operated
3. Controls on the places in which products may be operated
4. Controls on the number of products which may be operated to-
gether
5. Controls on noise emissions from the property on which products
are used
6. Controls on the licensing of products
7. Controls on environmental noise levels
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Federal regulations promulgated under section 6 preempt State or
local regulations which set limits on permissible noise emissions
from the new products covered by the Federal regulations at the time
of sale of such products, if they differ from the Federal regulations.
Conversely, State and local authorities are free to enact regulations
on new products offered for sale which are identical to Federal regula-
tions.
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SECTION 2
IDENTIFICATION OF TRUCKS AS A MAJOR SOURCE OF NOISE
In pursuit of subsection 5(b) of the Noise Control Act of 1972,
the Administrator has published a report (FEDERAL REGISTER, Vol.
39, No. 121, pp. 22297-9) which "identifies medium and heavy duty
trucks having a gross vehicle weight rating (GVWR) in excess of 10, 000
pounds as a major source of noise. " GVWR means the value speci-
fied by the manufacturer as the loaded weight of a single vehicle.
The following paragraphs will briefly describe the basis on which
trucks with a GVWR of 10,000 pounds or more were identified as a
major source of noise.
LEGISLATIVE BASIS
Subsection 6(a) of the Noise Control Act sets forth four categories
of products for which a noise emission standard can be proposed for
each product identified as a major source of noise. The categories
are:
1. Construction equipment
2. Transportation equipment (including recreational vehicles
and related equipment)
3. Any motor or engine (including any equipment of which an
engine or a motor is an integral part)
4. Electrical or electronic equipment
PRIORITY BASIS
The criteria developed by EPA to identify products which are major
sources of noise and for which noise emission standards are requisite
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to protect the public health and welfare stipulate that at this time
first priority has been given to products that contribute to community
noise exposure. Community noise exposure is that exposure exper-
ienced by the community as a whole as a result of the operation of a
product as opposed to that exposure experienced by the users of the
product.
DAY-NIGHT SOUND LEVEL BASIS
The day-night sound level, Lnd, has been specifically developed
as a measure of community ^oise. Since it is a cumulative energy
measure, it can be used to identify areas where noise sources operate
continuously or where sources operate intermittently but are present
enough of the time to emit a substantial amount of sound energy in a
24 hour period.
EPA has identified an outdoor Ldn of 55 dB as the day-night sound
level requisite to protect the public from all long-term adverse public
health and welfare effects in residential areas, and an Leq of 70
(roughly equivalent to an Ldn 70) as the threshold of hearing impair-
ment.
POPULATION BASIS
The estimated number of people in residential areas who are sub-
jected to urban traffic noise and freeway traffic noise at or above an
outdoor Ldn of 70, 65 and 60 dB is shown in Table 2-1 below:
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TABLE 2-1
NUMBER OF PEOPLE SUBJECTED (IN MILLIONS)
Urban Traffic Freeway Traffic
Outdoor Ldn (dB) Noise Noise
70 4-12 1-4
65 15-33 2-6
60 40-70 3-6
Source; BBN Report No. 2636, September 1973.
As indicated by Table 2-1, more than 70 million people in
residential areas are subjected to noise from surface transportation
equipment at or the outdoor Ldn of 60 dB. Thus, the surface transpor-
tation equipment category has been selected by EPA for regulatory
attention because of the extensive community exposure to noise emanat-
ing from products in this category.
PRODUCT BASIS
A two-step approach has been used to identify products within the
surface transportation equipment category which are major contribu-
tors to community noise exposure. First, the Ldn has been used to
identify residential areas selected from a composite derived from a
cross section of U. S. towns and cities where a large number of people
are exposed to high Ldn. Second, in these high Ldn areas, products
which are major contributors to the Ldn have been identified.
Table 2-2 lists the products in the highway surface transportation
equipment categories that are presently considered as major sources
of noise, and indicates both the typical sound pressure level (SPL)
at 50 feet associated with, each product and the estimated total sound
energy emitted per day by all existing models of each product.
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TABLE 2-2
MEASURES OF NOISE ASSOCIATED WITH TRANSPORTATION VEHICLES
Products in the Typical SPL Estimated Total
Transportation Equipment at 50 feet Sound Energy Per
Category dB(A) Day (Kilowatt-hrs)
Trucks (greater than 10, 000 Ibs GVWR)
Automobiles (sports compacts)
Automobiles (passenger)
Trucks (less than 10, 000 Ibs GVWR)
Motorcycles (highway)
Buses (city and school)
Buses (highway)
84
75
69
72
82
73
82
5800
1150
800
570
325
20
12
Source: BBN Report No. 2636, September 1973.
The typical sound pressure level in dB(A) at 50 feet is a measure
of the perceived loudness at that distance from the product when it
is operating. This measure suggests which products, when they are
operated alone, will be perceived as noisy by the community. The
estimated total sound energy per day is useful because it is an aggre-
gate measure that takes into account the sound energy emission rate
of the product, the number of products operating and the amount of
time they are operated each day. For trucks with a GVWR of 10, 000
pounds or more, this measure was estimated on the basis that there
are about 3.5 million trucks in use for an average of 4 hours per day.
These estimates are for a composite of both urban and freeway traffic
conditions. Note that the levels cited in Table 2-2 are estimated
average levels and, in the case of trucks, the actual level is probably
higher than that listed.
As indicated by Table 2-2, trucks with a GVWR of 10,000 pounds
or more are louder than other transportation vehicles and contribute
the most daily sound energy to the community environment of any
product in the surface transportation equipment category.
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SECTION 3
THE TRUCK INDUSTRY
THE ROLE OF TRUCKS IN DOMESTIC TRANSPORTATION MARKETS
Of the major means by which goods are transported, Table 3-1
implies that trucks are far from being the least expensive; yet, be-
cause of convenience, trucks account for over 80% of the total dollars
spent on moving domestic freight.
As shown in Table 3-1, trucks carry the largest share in tons
of domestic freight. The cost per ton-mile (approximately 17 cents)
is considerably more expensive than the cost (approximately 1.5 cents
per ton-mile) for shipping by rail, the next largest carrier of goods.
However, as can be inferred from Table 3-1, trucks on the average
carry more goods over shorter distances, and provide a flexibility that
cannot be achieved by other modes of transportation. Thus, the ac-
cepted presence of trucks on the nation's highways is supplemented by
their pervasive presence in virtually every street and roadway of the
country.
Over the period 1967 to 1972, total new truck sales increased 1. 3
times as fast as the gross national product; new heavy duty truck
sales increased more than 2.5 times as fast. (Reference 1). The
trend over the past several years has been for more and more goods
to be moved by truck. It is expected that this trend will continue and
that each year there will be more trucks on the nation's freeways,
highways, and city and residential streets.
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TftRT.F. 3-1
DOMESTIC FREIGHT TRANSPORTATION MARKET, 1970
Mode
Transportation
•Truck
Rail
Water*
Pipeline
Air
Totals
Tons
Millions Percent
1,684 34.2
1,572 32.1
867 17.6
790 16.1
3 0.0
4,916 100.0
Ton-Miles
Millions Percent
412,000 18.7
771,000 34.8
595,000 26.9
431,000 19.5
3,400 0.1
2,212,000 100.0
Revenue Dollars
Mill ions Percent
$69,084 81.3
11,869 14.0
1,902 2.3
1,396 1.6
720 .8
$84,971 100.0
10
* Includes Domestic Deepsea, Great Lakes and Inland Waterways.
Source; Transportation Facts and Trends, TAA Quarterly Supplement, April 1973.
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TRUCK DESCRIPTION FOR GENERAL PURPOSES
In describing trucks with gross vehicle weight ratings (GYWR)
greater than 10, 000 pounds, a wide range of vehicle types are involved.
At one extreme of the vehicle characteristics for different types of
trucks there are gasoline-powered 2-axle single vehicles with 4 tires
and GVWR of less than 13,000 pounds. At the other extreme there
are 11-axle combination vehicles with 42 tires, turbocharged diesel
engines and GCWRin excess of 130, 000 pounds. HereGCWR, the gross
combination weight rating, means the value specified by the manufac-
turer as the maximum loaded weight of a combination vehicle for which
it is designed.
Trucks can be described in terms of the following attributes: the
gross vehicle weight rating, the major designed use, the number of
axles, the type and size of engine, and the style of the cab.
Truck designation in terms of GVWR for trucks with GCWR over
10,000 pounds has been defined by the Motor Vehicle Manufacturers
Association (MVMA) and is shown in Table 3-2.
TABLE 3.2
TRUCK DESIGNATION BY GVWR (POUNDS)
10, 001 - 14, 000
14,001 - 16,000
16,001 - 19,500
19,501- 26,000
26,001 - 33,000
over 33,000
Source: MVMA's 1973 Motor Truck Facts.
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Figure 3-1, Short Conventional
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-••
Figure 3-2, Long Conventional Cab
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Figure 3-4, High Deck Cab-Over-Engine,
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There are three truck design designations which reflect the major
uses for trucks with GVWR greater than 10, 000 pounds. A ruggedly
built cab-chassis unit for mounting dump beds, concrete mixers, etc.,
is often referred to as a construction truck while a light cab-chassis
unit for mounting van bodies, etc., is designated as a delivery truck.
A truck-tractor for pulling trailers, etc., is called a line-haul truck.
The number of axles by which engine power is transmitted as
traction at the road surface can also be used for truck designation.
For trucks with two axles, one of which drives the truck (as in an
automobile), the designation is 2 x 4; i.e., two out of the four
wheels (dual tires count as one wheel) are driving. Similarly, a tan-
dem axle, truck-tractor is designated as a 4 x 6 and an all-wheel drive
truck is a 4 x 4 or a 6 x 6.
In terms of truck designation by the type of engine, trucks can
be designated simply as having either a gasoline engine or a diesel
engine. The horsepower rating of the engine can also be used for
truck classification purposes.
Trucks can also be designated by the style of the truck or truck-
tractor cab. The two main styles of cabs are the conventional cab
(sometimes termed a "fixed" cab) style and the cab-over engine (COE)
style. In a conventional cab, the driver sits behind the engine. Con-
ventional cab styles may be either "short" (see Fig. 3-1) or "long"
(see Fig. 3-2), depending on the length of the hood. In the COE
style, the driver is positioned above and to the side of the engine.
COE style may be either "low" (see Fig. 3-3) or "high" (see Fig.
3-4), depending on the distance of the deck, or floor, of the cab above
the ground.
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TRUCK CLASSIFICATION FOR PURPOSES OF NOISE REGULATION
The truck attributes most closely associated with truck noise
level include the gross vehicle weight rating, the number of axles,
and the size and type of the engine. All these attributes are some-
what related. For example, a truck with a large GVWR will tend
to have more axles and will more likely be powered by a large diesel
engine than a truck with small GVWR. GVWR is a prime candidate
for defining regulated truck classification. As Table 3-2 indicates,
the Motor Vehicle Manufacturers Association uses GVWR as a primary
variable in reporting its production figures. In addition, most states
register trucks according to GVWR.
A truck's GVWR depends on the sum of its axle weight ratings.
Thus, classification by the number of axles may be redundant. Classi-
fication by engine size could again be redundant as the size of the
engine selected for a given truck is inherently dependent on its design
GVWR.
The type of engine is another possible candidate for truck class-
ification for noise regulation since gasoline and diesel engines differ
somewhat in their noise characteristics (Reference 2). However, this
engine noise level difference becomes less pronounced, as the engine
component is considered in the totality of measured truck noise.
TRUCK CATEGORIES FOR PURPOSES OF REPORT DISCUSSION
Of newly manufactured trucks with a GVWR greater than 10, 000
pounds but less than 26, 000 pounds, almost 85% will be gasoline pow-
ered. Conversely, more than 96% of the trucks with GVWR greater
than 26, 000 pounds can be expected to be diesel powered.
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Accordingly, in this document, trucks with a. gross vehicle weight
rating in excess of 10,000 pounds have been categorized as "medium
duty" or "heavy duty" trucks as defined in Table 3. 3. Also defined in
Table 3. 3 are truck GVWR groups within each of these GVWR categories,
TABLE 3-3
GVWR Truck Categories
GVWR Category GVWR Group Range of GVWR
Medium Duty Trucks
(10,001-26,000 Ibs)
Heavy Duty Trucks
(over 26, 000 Ibs)
1
2
3
4
5
6
10, 001-14. 000
14,001-16,000
16,001-19, 500
19, 501-26, 000
26,001-33, 000
over 33,000
In addition to the above truck GVWR categorization, this document
will also on occasion further categorize trucks by type of engine as
either gasoline or diesel.
DISTRIBUTION OF TRUCKS BY CATEGORIES
A statistical analysis of the census data on the characteristics
and uses of the truck population in the United States, which was col-
lected and made available to EPA by the Bureau of the Census, provides
an estimate of the total truck population in the United States in 1972.
(For details, see Appendix O.) The total truck population with GVWR
in excess of 10,000 pounds in 1972 was estimated to be 3,533,000
trucks. The distribution of these trucks by GVWR category and type
of engine: is shown in Table 3-4.
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TABLE 3-4
TOTAL TRUCK POPULATION, 1972
GVWR
Category
Medium Duty
Heavy Duty
Totals
Gasoline Engine Diesel Engine
Number Percent Number Percent
2,335,000
509, 000
2, 844, 000
98
44
80
41,000
648,000
689,000
2
56
20
Total
Trucks
2,376,000
1, 157,000
3, 533,000
Source: A. T. Kearney Report to EPA, April 1974.
Table 3-5, a breakdown for diesel engine trucks by GVWR for
selected years between 1966 and 1972, shows a trend toward fewer
medium duty trucks being powered by diesel engines and a trend toward
increased use of diesel engines for heavy duty trucks, particularly
the larger GVWR group 6 trucks.
The distribution of new truck production in 1972, according to
GVWR category and group as well as type of engine, is shown in Table
3-6. Over 90% of the new trucks produced are used in domestic truck
transportation.
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TABLE 3-5
PERCENT OF DIESEL TRUCKS TO TOTAL TRUCKS BY CATEGORIES FOR SELECTED
YEARS, 1966-72
V
M
ro
Year
1966
1968
1970
1972
Medium Duty Trucks
GVWR Group
1234
0% 0% 1% 3%
0002
0003
0001
Total
4%
3
3
1
Heavy Duty Trucks
GVWR Group
5 6
5% 19%
4 21
4 28
3 30
Total
24%
25
32
33
Source: MVMA 1973 Motor Truck Facts .
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TABLE 3.6
NEW TRUCK PRODUCTION, 1972
GVWR
Category
Medium Duty
Heavy Duty
Totals
GVWR
Group
1
2
3
4
5
6
Totals
Gasoline Engine Diesel Engine Total
Number Percent Number Percent Trucks
227,263
41,994
269,257
44.221
9.397
26,330
147,315
25,364
16,630
269,257
98
23
S5"
100
98
100
97
65
12
65
5,045
138,044
143,089
0
215
31
4,789
13,563
124,481
143,089
2
77
•33"
0
2
0
3
35
88
75"
232,308
180,038
412, 346
44,221
9,612
26, 371
152,104
38,927
141,111
412, 346
Source: (Reference 1)
Medium duty trucks account for the larger share of new trucks
with GVWR in excess of 10, 000 pounds produced in 1972.
MAJOR TRUCK USERS
A listing of the major users of trucks to move goods is given in
Table 3-10. As shown, the agricultural industry is the principal user
of trucks and, in particular, the largest user of medium duty trucks.
As elso shown in Table 3-10, the largest user of heavy duty trucks
is the truck-for-hire industry.
TRUCK MANUFACTURERS
The number of new trucks produced by the major truck manu-
facturers in 1972 are shown in Table 3-7. Four truck manufacturers,
General Motors (including its Chevrolet Division), Ford, International
Harvester and Dodge, produce almost 98% of all medium duty trucks
and approximately 60% of the heavy duty trucks.
3-13
-------
TABLE 3-7
NUMBER OF NEW TRUCKS BY MANUFACTURER, 1972
Truck
Manufacturer
Chevrolet
Diamond Reo
Dodge
FWD
Ford
CMC
IHC
Mack
White
Others
Totals
Medium Duty Trucks
Gasoline Diesel
53,722 135
37
45,042 278
4 8
63,544 3,010
25,568 446
39,064 1,165
0 0
0 3
282 0
227,263 5,045
Total
53,857
37
45,320
12
66,554
26,014
40,229
0
3
282
232,308
Heavy Duty Trucks
Gasoline Diesel
1,602 3,696
1,044 3,207
3,623 1,480
301 606
13,952 18,824
8,126 16,017
12,230 29,311
25 26,331
753 21,854
338 16,718
41,994 138,044
Total
5,298
4,251
5,103
907
32,776
24,143
41,541
26356
22,607
17,056
ISO.OSS
I
M
*-
Sourde: (Reference 1)
-------
The financial characteristics of the parent companies of the major
truck manufacturers is shown in Table 3-8. Of these parent companies,
the five that are considered large, have sales and assets in excess
of $1 billion; two have sales or assets between $500 million and $1
billion; and four smaller companies have less than $100 million in
sales and assets.
In general, it can be expected that the larger parent companies
would have the least difficulty financially in complying with the new
truck noise regulations. Smaller companies, without equivalent in-
house research and development programs, may have to rely on the
noise reduction provided by the suppliers of truck components in order
to comply with the noise regulations.
The suppliers of truck components which may be particularly
affected by truck noise regulation are those producing engines, mufflers
and fans. Most truck manufacturers rely heavily on two major diesel
engine suppliers, Cummins and Detroit Diesel, as shown in Table 3-9.
The Detroit Diesel Division of General Motors produces most Chev-
rolet and GMC diesel engines. Mack Truck uses an integrated approach
to produce mated engines and transmissions.
3-15
-------
TABLE 3-8
FINANCIAL CHARACTERISTICS OF TRUCK MANUFACTURER'S
PARENT COMPANY, 1972 ($ Millions)
Parent Company of
Truck Manufacturer
General Motors Corporation
Ford Motor Company
Chrysler Corporation
International Harvester Company
The Signal Company (Mack)
White Motor Corporation
Paccar, Inc.
Diamond Reo Trucks, Inc.
Hendrickson Manufacturing Co.
FWD Corporation
Oshkosh Truck Corporation
Net
Sales Income Assets
$30,435 $2,163 $18,273
20,194 870 11,634
9,759 221 5,497
3,527 87 2,574
1,481 41 1,328
943 9 573
595 30 268
83 7 30
44 Not 23
Available
28 . 4 25
22 .3 14
Net Worth
$11,683
5,961
2,489
1,198
653
222
170
5
15
6
7
Comments <•
Truck producing divisions are
Chevrolet and CMC.
For year ended 10/31/72.
Truck producing subsidiary is
Dodge Trucks, Inc.
Truck producing subsidiary is Mack.
Including Brockway, a Division of Mack,
had consolidated sales of $713 million
and net income of $35 million.
Truck producing divisions are Auto-
car, White, Freightliner and Western
Star. Total truck sales of these
groups were $611 million with
earnings of $27 million in 1972.
Truck producing subsidiaries are
Kenworth and Peterbilt. On and off-
highway trucks produced by Peterbilt,
Kenworth and Dart represents about
75% of sales.
Sales include trucks, special truck
equipment, and truck modifications.
Sales primarily trucks, year end
9/30/72. FWD is a subsidiary of
Ocwen Corporation, and investment
company.
Sales primarily trucks.
Source-' (Reference 1)
-------
TABLE 3-9
SUPPLIERS OF DIESEL ENGINES USED BY TRUCK MANUFACTURERS, 1972
Truck
Manufacturers
Chairs Caterpillar Cummins g*™* CMC IHC Mack Perkins cax
Total
I
M
>g
Chevrolet
Diamond Reo
Dodge
FWD
Ford
CMC
IHC
Mack
White
Others
22
44
308 3,388 135
129 2,038 1,040
1,046 434 278
1 165 448
9,336 4,759 7,739
1,255 14,599 609
747 11,830 14,475 2,742 628
331 2,612 1,584 21,121 661
779 15,513 5,501 '
3,736 8,983 3,999
3,831
3,207
1,758
614
21,834
16,463
30,476
26,331
21,857
16,718
Totals
66
15,079
48,509 53,207 744 2,742 21,121 960
661
143,089
Source: (Reference 1)
-------
TABLE 3-10
DISTRIBUTION OF TRUCKS BY MAJOR USERS,
Major User of Trucks
Agriculture
Wholesale and Retail Trade
Construction
For-Hire
Services
Personal Transportation
Manufacturing
Utilities
Forestry and Lumbering
Mining
All Other
Medium Duty
32. 5%
19.8
11.1
6.3
9.5
9.0
3.6
3.4
1.7
.6
3.0
Heavy Duty
10.3%
18.3
19.1
30.6
2.5
1.0
8.5
1.9
3.6
1.9
2.3
Total
26.3%
19.4
13.4
13.4
7.5
6.7
5.0
2.9
2.3
1.0
2.1
Source: Developed from Truck Inventory and Use Survey, 1972 Census of
Transportation.
3-18
-------
REFERENCES FOR SECTION 3
1. A. T. Kearney & Company, A. T. Kearney Draft Report to U.S.
Environmental Protection Agency, April 1074.
2. Bolt, Beranek and Newman, Inc., BEN Report No. 2710, "The
Technology and Cost of Quieting Medium and Heavy Trucks, "
January 1974.
3-19
-------
SECTION FOUR
INFORMATION BASE
SOURCES USED FOR DEVELOPING INFORMATION
The information presented in this document was developed frorr.
(1) studies performed by staff personnel of the Standards and Regu-
lations Division, Office of Noise Abatement and Control (ONAC) , U. S.
Environmental Protection Agency; (2) studies performed under con-
tract to ONAC; (3) submissions by other Federal agencies; (4) sub-
missions by the private sector; and (5) the open literature.
The studies dealing with considerations of public health and wel-
fare were prepared by ONAC personnel. The data used are based large-
ly on previous EPA reports (References 1, 2, 3, 4 and 5) and resulted
from intensive analysis of existing information, such as the proceed-
ings of an international conference on noise as a public health problem
(Reference 6). The methodology developed assesses the statistical
effects of various possible regulatory standards on the noise reduction
achievable and the change in the equivalent number of people impacted
by vehicle noise in urban areas of the United States. Numerous truck-
community scenarios (see section 6 of this document) were also de-
veloped to evaluate the situational impact of truck noise on people
in particular work and home situations.
Studies of noise control technology, the cost of compliance with
such technology, if and when applied, and the economic impact on the
truck manufacturers and associated truck component industries were
largely the result of data acquired by firms under contract to EPA.
The technology to reduce truck noise from current levels is presented
4-1
-------
in reports prepared by Bolt Boranek and Newman, Inc. (Rot'cronce
7) and by Wyle Laboratories (Reference 8). These reports also pro-
vide their estimates of the costs associated witli the technology appli-
cations they cite. An economic impact analysis is discussed in a report
prepared by A. T. Kearney (Reference 9). This report uses cost
data as an impact for projections on such quantities as changes in truck
sales and truck operating costs.
The National Bureau of Standards, working under an Interagency
Agreement with EPA, provided assistance in the review (Reference 10)
of truck noise test procedures. Statistical use was made of the truck
resource information provided by the Bureau of the Census of the
Department of Commerce (Reference 11). The Department of Transpor-
tation provided reports resulting from the Quiet Truck Program
(Reference 12).
Information was also provided by the public sector in response
to the Advance Notice of Proposed Rule Making (ANPRM) for new
medium and heavy duty trucks published in the FEDERAL REGISTER
on February 27, 1974 (39 FR 7955). The responses (Reference 13)
received from industry, State and local governments, and other inter-
ested parties, are recorded in EPA Docket No. ONAC 74-2, which is
available for inspection at the U. S. EPA Headquarters, 401 M Street,
S. W., Washington, D. C. 20460.
Additional sources of pertinent information, particularly published
articles from journals and the like, are also included in the references
shown at the end of each section of this document.
4-2
-------
BASELINE NEW TRUCK NOISE LEVELS
The baseline noise levels, for considering alternative regulatory
options in the development of the new truck noise regulation, are those
noise levels generated by current production trucks. This section dis-
cusses these baseline noise levels for different truck categories as
well as the test procedure used to determine the noise levels indicated.
TEST PROCEDURE USED
The most widely used test in the United States for measuring noise
levels for trucks with a GVWR in excess of 10,000 pounds is that
established by the Society of Automotive Engineers (SAE) for determ-
ining the "Exterior Sound Level for Heavy Trucks and Buses" and is
commonly referred to as the SAE J366 test. In April 1973 the test
was revised, making it an SAE Standard (J366b) rather than an SAE
Recommended Practice. The majority of the truck noise level data
in this document was measured using the SAE J366a recommended
practice test procedure. No significant changes in the test procedure
were made in this SAE J366b revision. Accordingly, the previous new
truck noise level data based on J366a are used herein as the base-
line noise levels for current production trucks. A brief description
of the SAE J366b test procedure follows, with a detailed description
of the test is included in Section 9.
The test site for performing the SAE J366b exterior truck noise
level cest is illustrated in Figure 4-1. A microphone is located 50
feet from the truck path. The truck approaches the acceleration point
with the engine operating at about two thirds of maximum rated or
governed engine speed. At the acceleration point, the accelerator
4-3
-------
is fully depressed and the truck accelerates, reaching the maximum
rated or governed RPM within the end zone of the acceleration lane.
Several runs are performed in different directions and the average
A-weighted sound level of the two highest readings within 2 dB of
each other corresponding to the noisiest side of the vehicle are
End Zone in Which
To Reach Max.
Rated RPM
Figure 4-1 Test Site for SAE J366b.
reported. During the test, the truck never exceeds 35 mph. Since
tires are relatively quiet at low speed, the J366 test results are pri-
marily an indicator of propulsion noise, including noise from the cooling
fan, air intake, engine, exhaust, transmission, and rear axle.
A histogram of the noise levels of new diesel trucks, measured
4-4
-------
*^r *r
8O
OF TRUCKS
•
~
_
- rr1"
i
.7 dB(A)
2.24 dB(A)
i
•1
rf
1
I I
i
1
.
3
.1
|f
5
t
/
*
I
i
1 1
i . '—^n
78 80 82 84 36 88 90
SOUND LIVEL ( dB (A)
92
Figure 4-2 Histogram of New Diesel Truck Noist>. Levels.
Source: BBN Report No. 2''10, January 1974.
-------
according to the SAE J366 test procedure, is shown in Figure 4-2.
For the total of 384 diesel trucks measured, the mean noise level
was 84.7 dB(A) with a standard deviation of 2.24dB(A). The trucks
measured included trucks from the eight truck manufacturers which
produced approximately 85% of the new diesel trucks sold in 1971.
Not included in this total are experimental trucks such as those devel-
oped under the Quiet Truck Program of the Department of Transporta-
tion or those trucks developed by various truck manufacturers without
government sponsorship.
Data on the noise levels of new trucks with gasoline engines are
presented in the histogram shown in Figure 4-3. For the total of
18 trucks measured, the mean level was 83.5 dB(A) with a standard
deviation of 2.35 dB(A). The difference between the mean noise level
of gasoline and diesel powered new trucks is 1. 2 dB(A).
10
Total Trucks-. 18
Mean Level: 83.5 dB (A)
Std. Deviation: 2.35 dB(A)
n
j
TO'7580 65 ?0
^;.- SOUND LEVEL (dB (A))
Figure 4-3 Noise Level Histograms of Gasoline-Powered Trucks.
Source: BBN Report No. 2710, January 1974.
4-6
-------
A cumulative distribution of the new diesel truck noise levels is
shown in Figure 4-4. Approximately 1% of newly manufactured 1973
trucks produce 80 dB(A) or less, 30% produce under 83 dB(A), and
86%produce less than 86 dB(A). Nevertheless, several new trucks
did produce noise levels in excess of 90 dB(A).
Histograms of the noise levels measured for new gasoline-powered
medium and heavy duty trucks are shown in Figure 4-5. The mean
noise level for medium duty trucks appears to be less than. 2 dB(A)
lower than the mean noise level for heavy duty, gasoline powered new
trucks.
4-7
-------
99.9
99.5
-I ••
% 98
_l
o «»
O 90
3
'
u
70
50
to
o
ce
fe »
I
80
84 88 92
SOUND LEVEL (dB(A))
Figure 4-4 Cumulative distribution of New Diesel Truck Noise Levels.
Source: BBN Report No, 2710, January 1974,
4-8
-------
10
MEDIUM DUTY
Total Trucks: H
Mean Level: 62.9 dO (A)
Std. Deviation: 2LG3 dB (A)
I
70 75 80 85 90
SOUND LEVEL (dB(A))
10
HEAVY DUTY
Total Trucks; 7
Moon Level-. 84.7 dB (A)
Std. Deviation: 1.33 dB. (A)
a
I
z
I
70 75 80 09 90
SOUND LEVEL (dB(A))
Figure 4-5 Noise Level Histograms of Gasoline-Powered Medium and
Heavy Duty New Trucks.
Source: BBN Report No. 2710, January 1974
4.9
-------
The preceding paragraphs discuss noise levels produced by new
trucks when operating under low speed, high acceleration conditions.
In the following paragraphs the noise generated by trucks travelling at
relatively high speed is examined. This information was extracted
from a draft of the "Background Document for Interstate Motor Carrier
Noise Emission Regulations. " It constitutes the basis for regulatory
level of 90 dB(A) which has been proposed for interstate motor car-
riers.
In the surveys presented in this section, an effort was made to
maintain standard conditions at almost all sites. Suitable instrumen-
tation was used; sound level meters met the requirements of ANSI SI. 4-
1971, American National Standard Specification for Sound Level Meters.
Microphone calibration was performed by an appropriate procedure and
at prescribed intervals. An anemometer was used to determine wind
velocity, and microphones were equipped with suitable wind screens.
Restrictions were made to prevent measurements during unfa-
vorable weather conditions (e.g., wind and precipitation). The stand-
ard site for passby measurements was an open space free of sound
reflecting objects such as barriers, walls, hills, parked vehicles, and
signs. The nearest reflector to the microphone or vehicle was more
than 80 feet away. The road surface was paved, and the ground
between the roadside and the microphone was covered by short grass
in most cases.
4-10
-------
T he standard site for the stationary runup test included apace
requirements that were the same as for pass-by measurements, and
the surface between the microphone and vehiclewas paved. Micro-
phones for stationary and pass-by measurements were located 50 feet
from the centerline of the vehicle or lane of travel, 4 feet off the
ground, and oriented as per manufacturer's instructions. Variations
from the standard measurement sites and microphone locations wor^
allowed if the measurements were suitably adjusted to be equivalent
to measurements made via the standard methods. Exact procedures
for the tests are included in the appendix.
Truck noise surveys have been conducted in California in 1965
and 1971, intheState of Washington in 1972, andinNew Jersey in 1972.
In 1973, EPA contractors conducted additional truck noise surveys of
6, 875 trucks operating at speeds over 35 mph in the states of Califor-
nia, Colorado, Florida, Maryland, Missouri, Texas, and Virginia.
4-11
-------
In almost all cases, measurements were made at a distance of 50
ft from the center of the first (outer) lane of travel, using A-weighting and
fast response of the sound level meter. In the 1973 surveys, the type of
truck and number of axles were recorded in order to permit detailed anal-
yses of the noise level distributions for various types of trucks.
In addition, a study of noise levels of 60 trucks produced during a sta-
tionary run-up test was carried out by EPA in Virginia in February 1974.
Figure 4. 6 shows cumulative probability distributions for the peak passby
noise levels measured at 50 ft under high-speed freeway conditions in the
surveys conducted prior to 1973. The data shown are for heavy trucks;
5, 838 diesel trucks in California in 1965, 172 combination trucks in Cal-
ifornia in 1971, 531 trucks with 3 or more axles in Washington in 1972,
and 1,000 trucks with 3 or more axles in New Jersey in 1972. The data
are in close agreement: typically, 50% of the trucks were observed to
exceed 87 to 88 dB(A) and 20% were observed to exceed 90 dB(A).
Figure 4. 7 shows that under high-speed freeway conditions, buses are
about 2 dB quieter than heavy trucks. Approximately 50% exceed 85 dB(A)
and 6% exceed 90 dB(A). These data were obtained in New Jersey in 1973.
Table 4.1 shows the mean noise levels and percentages of all trucks
with six or more wheels that were observed to exceed 90. 0 dB(A) under
high-speed freeway conditions in ten states. These data were obtained in
1973, except for the Washington state data, which were obtained in 1972
The arithmetic mean of the percentage of trucks exceeding 90 dB(A) is
23.1%. When the data is weighted by the sample size obtained in each state
this percentage drops to 22. 6%. When the data are weighted by the number
of registered trucks above 10, 000 Ib GVWR/GCWR, the percentage drops
to 21.0%.
4-12
-------
99.0
WR
99.5
99
98
95
90
80
70
1 60
5 50
.E 40
C
1 30
"8 '
•5 20
#
10
5
2
1.0
0.5
0.2
0.1
0.05
0.01
*^»_ ^L.
X
^
\x
•\
S
\ V
Data
OCa
nCa
AWl/-
— • O Mr
Ni\^\
°V\
^V^S
Source ,
lifornia 11971) 172 Combination Vehicle
lifornia (1965) 5.838 Diesel Trucks
shington M972) 531 Trucks,
3 or More Axles
w Jersey (1972) 1000 Trucks
3 or More Axles
a
2v\
m
i
i
*
'i
'
i
r
1
i
V^A
\l\kn
i
••
.
^»A\lS
AV^5v
^
.
V
\
•
*A
•v *•*
V v
J ... ._
•
^A
i
\
SA
X*
80 82 8« f$ %n> ?P 9;? 94
' -sfircerr.eiu Limii. db(A.) at 50 Ft
Figure 4.6 Enforcement :'JmJ-'., dB(A) At 50 Ft
96
98
100
4.1?.
-------
»».u
99.8
99.5
o 99
2 98
I 95
i eo
i
5 80
5
i 7°
* 60
0
5 50
C 40
jj 30
I 20
t»
s
s: 5
2
1.0
0.5
0.2
A i
~" \
\
V
— \
\
•
'' <
"X
—
i
I
\
\ N
%
\
,
"'^<-v
1
1
I '
«-»AII Trucks (N = 1394)
»°-AII Buses (N - 93)
\
-\
^S \
\
\
I
\
k\
\ \
A
\
-
1
1
\
\
1
1 '""
—
—
•
—
—
—
—
—
^V ""
76 80 84 88 92 96 too
Peak Passby Noise Level, dB(A) at 50 ft
Figure 4.7 Cumulative Distribution Of Peak Passby Noise Levels For All
Trucks And All Buses At Speeds Over 35 MPH
4-14
-------
Table 4-1 ,
ALL TRUCKS ABOVE 10,000 LBS GVWR OR GCWR
State
•MMMMMB
CA
CO
IL
KY
MD
NJ
NY
PA
TX
WA
Source
W.L.
BBN
BBN
BBN
Md.DOT
BBN
BBN
W.L.
BBN
WA-72
Mean Noise
Level
85.4dB(A) (a)
84.6
89.1
88.8
88.1
87.2
88.8
8C. 2 (a)
83.7
86.6 (a)
Mean Speed
.
51. 7mph
57.2
61.3
-
56.5
60.0
-
56.1
-
% Above
90. 0 dB(A)
5.0%
10.0
42.0
40.0
30.0
20.0
43.0
13.0
12.5
16.0
mean percentage exceeding 90 dEKA) = 23.1%.
(a) median
4-15
-------
Table 4-3 shows the same results by type of truck for the nine
states in which data were obtained in 1973. The mean percentages of
trucks exceeding 90.0 dB(A) ranges from 1.9% of 2-axle trucks to
36. 1% of 5-axle trucks.
A crucial distinction must now be made. The fact that approx-
imately 23% of all trucks observed in these surveys exceeded 90. 0
dB(A) does not mean that 23% of all registered trucks above 10,000
Ib GVWR/GCWR will exceed this level. This is because larger trucks
operate many more miles per vehicle per year than smaller trucks do
and accordingly show up more frequently in surveys than their actual
numbers would indicate. For example, 2-axle trucks average 10, 600
vehicle miles per year, while 5-axle trucks average 63,000 vehicle
miles per year (60).
Using data from the 1972 Census of Transportation - Truck Inven-
tory and Use Survey, the following breakdown was obtained for the
population of registered trucks above 10, 000 Ib GVWR/GCWR.
TABLE 4-2
2-axle straight truck 71.7%
3-axle straight truck 10. 6%
3-axle combination truck 2.4%
4-axle combination truck 5.3%
5-axle combination truck 8.1%
Not reported or other 1.9%
100. 0%
Table 4-4 shows that when the percentages shown in Table 4-2
are multiplied by the mean percentages of each type exceeding 90. 0
dB(A) from Table 4-3, a total of about 7% of all registered trucks above
10, 000 Ib GVWR/GCWR exceed 90. 0 dB(A) at freeway speeds.
4-16
-------
Table 4-3
2 AXLE STRAIGHT TRUCK ABOVE 10,000 LBS GVWR
State
CA
CO
IL
KY
MD
NJ
NY
PA
TX
Source
W.L.
BBN
BBN
BBN
Md. DOT
BBN
BBN
W.L.
BBN
Moan Noise
Level
81.0dB(A) (a)
80.4
83.1
82.9
83.9
82.3
85.1
81. 2 (a)
78.6
Mean Speed
-
50. 9mph
'55.7
57.7
-
55.7
59.4
-
54.6
% Above
90.0 cin(A)
1.2%
1.9
1.0
1.0
3.5
0.6
6.0
0.9
0.6
mean percentage exceeding given
noise level:
1.9%
3 AXLE STRAIGHT TRUCK
CA
CO
IL
KY
MD
NJ
NY
PA
TX
W.L.
BBN
BBN
BBN
Md.DOT
BBN
W.L.
W.L.
BBN
85. 2 (a) (b)
84.1
85.8
87.7
87.5
84.7
88. 0 (a) (b)
84. 5 (a) (b)
84.8
-
47.7
54.5
59.9
57.4
-
-
50.6
8,0
1.2
9.0
*
. *
*
26.0
2.0
*
mean percentage exceeding given
noise level:
9.3%
(a) median
Co) all 3 axle trucks
* insufficient data
4-17
-------
Table 4-3 (lontinueu;
3 AXLE COMBINATION TRUCK
State
CA
CO
IL
KY
MD
NJ
NY
PA
TX
mean
noise
CA
CO
IL
KY
MD
NJ
NY
PA
TX
Source
W.L.
BBN
BBN
BBN
Md.DOT
BBN
W.L.
W.L.
BBN
Mean Noise
Level
85. 2 (a) (b)
83.8
86.0
87.8
86.6
85.7
88. 0 (a) (b)
84. 5 (a) (b)
83.0
Mean Speed
-
51.9
55.7
59.0
-
57.2
mm
-
56.5
percentage exceeding given
level:
4 AXLE
W.L.
BBN
BBN
BBN
Md.DOT
BBN
BBN
W.L.
BBN
COMBINATION
84.2 (a)
84.8
87.1
88.0
87.9
86.7
88.8
85. 7 (a)
83.9
TRUCK
- •
49.0
55.4
61.0
-
57.7
58.8
-
56.4
% Above
90. 0 dB(A|
8.0%
*
17.0
1.0
26.0
2.0
10.8%
3.0
9.0
22.0
24.0
26.0
11.0
26.0
9.0
4.5
mean percentage exceeding given
noise level: 15. o%
(a) median
(b) all 3 axle trucks
* insufficient data
4-18
-------
Table 4-3 (Continued)
5 AXLE COMBINATION TRUCK
State
CA
CO
IL
KY
MD
NJ
NY
PA
TX
Source
W.L.
BBN
BBN
BBN
Md. DOT
BBN
BBN
W.L.
BBN
Mean Noise
Level
85. 9 (a)
87.0
90.2
90. G
89.7
88.3
91.2
87. 6 (a)
87.5
Mean Speed
53.7
57.7
62.6
• _
58.7
61.6
-
57.9
% Above
90.0 clB(A)
7.0%
18.0
51.0
56.0
42.0
32.0
74.0
22.0
23.0
mean percentage exceeding given
noise level: 36.1%
(a) median
4-19
-------
Tablc4-4
TRUCKS EXCEEDING 90.0 dBA AT SPEEDS OVER 35 MPH
% of all
trucks above
lO.OOOlbs (a)
71.7%
10.6
2.4
5.3
8.1
1.9
100. 7%
% of type
exceeding
90. 0 dB(A)
1.9%
9.3
10.8
15.0
36.1
38.1 (c)
% of all trucks
above lO.QOOlbs
jffected (a)
1.4%
1.0
0.3
0.8
2.9
0.7
7.1%
2 axle straight truck
3 axle straight truck
3 axle combination
4 axle combination
5 axle combination
All other (1>)
(a) Estimates are for all trucks over 10,000 pounds GVWR or GCWR,
including trucks not involved in interstate commerce.
(b) "All other" includes straight truck with trailer, combinations with
6 or more axles, and combinations not specified in the 1972 Census
of Transportation survey.
(c) No data available. Percentage exceeding noise level is assumed to
be the same as for 5 axle combinations.
4-20
-------
It is useful to note that truck noise which is predominantly tire
noise may be estimated by the empirical formula given on Page 5-15.
In particular the effect of a velocity change from speed V± mph to v2
mph corresponds to a decrease in noise level (C ) of 40 , (vi / vo^
•Iogio1/
dB(A). When (v )is 65 mph and (v2) is 50 mph the noise level reduction
is 4. 6 dB(A). Thus trucks travelling at 65 mph and which generate a
noise level of 90 dB(A) would produce 85.4 (approximately 86 dB(A)
at 50 mph. This is of significance in comparing noise levels measured
in the high speed test described in this document.
4-21
-------
REFERENCES FOR SECTION 4
1. Noise Control Act of 1972, Public Law 92-574, 92 Congress,
H. R. 11021, October 1972.
2. "Report to the President and Congress on Noise, " EPA Report
NRC 500.1, December 1971.
3. "Public Health and Welfare Criteria for Noise, " EPA Revert
550/9-73-002, July 1973.
4. "Impact Characterization of Noise Including Implication a r.f
Identifying and Achieving Levels of Cumulative Noise Exposure, "
EPA Report NTID 73.4, July 1973.
5. "Information on Levels of Environmental Noise Requisite to
Protect Public Health and Welfare with an Adequate Margin of
Safety, " EPA Report 550/9-74-004, March 1974.
6. "Proceedings of the International Conference on Noise as a
Public Health Problem, " EPA Report 550/9-73-008, May 1973.
7. "The Technology and Cost of Quieting Medium and Heavy Trucks,
BBN Report No. 2710, January 1974.
8. "Cost Effectiveness Study of Major Sourcon of NolHe; Voi I -
Medium and Heavy Trucks," Wyle Laboratories Report No. Wi{
73-10, October 1972.
9. "A Study to Determine the Economic Impact of Noise Emissf.cn
Standards in the Medium and Heavy Duty Truck Industry,!! A, T
Kearney Report (Draft), April 1974.
10. Methodology and Supporting Documentation for the Measurenvur.t
of Noise from Medium and Heavy Trucks; NBSIR 74-517, Nation-
al Bureau of Standards, Washington, D. C., June 1974, W. A,
Leasure and T. L. Quindry.
11. "1972 Truck Inventory and Use Survey" (Magnetic Tape), U.S.
Department of Commerce, Bureau of the Census, 1972.
12. "Quiet Truck Program," U.S. Department of Transportation,
1972.
13. Response to Advanced Notice of Proposed Rule Making: Noise
Emission Standards for New Products - New Medium and Heavy
Duty Trucks, EPA Docket No. ONAC 74-2, April 1974.
4-22
-------
SECTION 5
NOISE ABATEMENT TECHNOLOGY
COMPONENT NOISE CONTROL
Of the truck components that contribute to total truck noise
levels, the most significant are the engine, fan, intake, exhaust,
and tires. The relative importance of each of these sources varies
according to the type of truck operation. This section describes
noise abatement techniques for reducing the component source levels.
Engine
Internal combustion engines convert the chemical energy of fuel
to mechanical energy through the controlled combustion of fuels in a
combustion of fuels in a cylinder. The motion of engine components
and the sudden increase in cylinder pressure occurring during com-
bustion excites the engine structure, causing vibration of the external
surfaces and attendant sound radiation. The magnitude of the radiated
noise depends primarily on engine type and design, not on engine size
or power.
Gasoline-fueled engines tend to be quieter than diesel-fueled
engines. The reason for this is that in present production diesel
engines the combustion forces are greater, especially in the mid
to high frequencies where resonant structural modes are present in
the engine.
Figure 5-1 shows engine noise source levels at 50 feet as a func-
tion of engine horsepower. Figure 5-1 is a histogram of these source
levels. The three gasoline-fueled engines are in the 75 to 77 dB(A)
5-1
-------
N>
90
LJ
>
Ld
LL)
o
O
w
UJ
z
o
z
LJ
80
70
1OO
200 300
ENGINE FLYWHEEL HORSEPOWER
>
© GASOLINE "ENGINE
O DIESEL ENGINF
O
1 1
vsrAueo *K
o
o c
o
^
o
8
o
0
o Q
s
o
o
o o
0 °
> o o
t
0
o <1
•O C
>
o 1
o <
0
c
o
i
0
o
400
05
00
O1
TO
(D
§
a
> s*
C (D
(D
OJ
3 2.
C «D
t ?
OQ 3
: t
OJ
ft
m
i
<° O
r B
Figure 5-1 / Engine Noise as a Function of Horsepower.
-------
CASOLINE ENGINE
7» ,0
vt
w
2
5
5 5-
u.
O
SOUND LEVEL, dB(A)
DIESEL ENGINE
J
-^
SOUND
"*
dB(A)
Figure 5-2 Histograms of Heavy
Truck Engine Structure
Noise (Engine in Truck)
5-3
-------
Possible noise control treatments include modifications to the
engine itself and modifications to control the path by which engine
structural noise is radiated to the exterior. The choice of method
will depend on the degree of noise reduction required, cost, lead
time, and any associated penalties in performance.
Reduction of combustion-related noise would be particularly de-
sirable for diesel engines. However, reducing this noise by reducing
combustion power would also entail a reduction in engine output power.
An alternative approach is to smooth out the rapid rise in pressure
(Reference 1). One method of doing this is to control the fuel delivery
rate, but with present production tolerances in the injection system
this would be difficult. Another method is to use a turbocharger on
4-stroke cycle engines. Turbocharging increases peak cylinder pres-
sures while decreasing the rate of pressure rise. Still another tech-
nique is to redesign the combustion chamber and injector spray pat-
tern (Reference 2). At present, all these solutions are being tested
by the major engine manufacturers. One major manufacturer is phas-
ing all naturally aspirated engines out of production and replacing
them with turbo charged models.
Control of machinery-related forces (e.g., oscillating pistons
slapping the cylinder walls; see Reference 3) in present engines is
aimed primarily at changing or reducing the structural response of
the engine. Investigators are experimenting with better ways to sup-
port the piston in the cylinder and are trying to obtain better balance
and closer tolerances in production engines. This technique, in com-
5-4
-------
lunation with turbocharging, was usod by one manufacturer to reduce
the overall noise of a diesel-powered truck to 75 dB(A).
Several engine manufacturers are presently marketing quieting
packages that attenuate engine structural noise by altering its trans-
mission path. Depending on the particular quieting package and truck
configuration, engine noise reduction ranges from 0 to 4 dB(A), with
most packages providing about 2 to 3 dB(A) reduction. The packages
generally consist of covers for the sides of the engine block and oil
pan, vibration isolation of the valve covers or air intake manifolds
and crossovers and, possibly, damping treatment on sheet metal cov-
ers (Reference 4). Thien (Reference 5) reports that close-fitting
covers which extend over the entire engine structure provide about
15 to 20 dB(A)reduction in engine noise. Discussions with one major
engine manufacturer indicated that such packages could reduce the
overall truck noise by 10 to 15 dB(A). However, the engine manu-
facturers also indicated that these packages are not presently ac-
ceptable for production utilization because problems with cooling and
service access have not yet been resolved.
To obtain the lowest possible overall truck noise level, most
engine manufacturers appear to prefer an enclosure built into the
truck cab rather than fitted onto the engine. Three truck manufac-
turers (International Harvester, White, Freightliner) under contract
to the U.S. Department of Transportation (DOT) have investigated
enclosure designs for cab-over engine trucks. The enclosures
involved a tunnel configuration with the cooling fan at the enclosure
5-5
-------
entrance. Air flows through the enclosure and around the engine via
acoustically lined ducts. All three manufacturers have built proto-
type vehicles generating less that 80 dB(A). The Freightliner truck
has an overall noise level of 72 dB(A) (Reference 6). This truck uses
a large frontal area radiator to reduce cooling fan requirements; the
large engine tunnel formed by the underside of the cab gives the cool-
ing air room to flow past the engine. Thus, full or partial engine
enclosures built into the cab structure ar'e technologically feasible.
These enclosures will be necessary to reduce the overall noise of
trucks equipped with standard diesel engines to low levels (75 dB(A)
and bolow). Some current production trucks without enclosures oan
be quieted to 80 dB(A). This reduction, however, is dependent upon
engine type.
Fan
Truck cooling fans have been designed with primary emphasis
on purchase price rather than on aerodynamic efficiency or noise
abatement. Accordingly, most fans are made of stamped sheet metal
blades riveted to a hub that is turned by means of a belt and pulley
arrangement connected to the engine. The fans tend to be small
and operate at high speeds, which leads to high noise levels, since
fan noise generation is proportional to fan speed. The fan cross
section is not aerodynamically shaped, and the blade pitch angle does
not vary with radius as it should if it is to properly develop uniform
flow through all portions of the radiator. In order to minimize
tractor length, it appears that manufacturers tend to squeeze the
5-6
-------
fan between the engine and radiator. Under favorable conditions,
the f&n would move air axially; in the usually cramped engine
compartment, the flow is mostly radial, with a nonuniform velocity
Noise data for various truck fans are shown in Figures 5-3 and
5-4 as a function of engine flywheel horsepower. The brackets <."i
the :"ive points in the 300 to 400 hp region designate limits of unce"--
taint" resulting from 0.6 dB(A) levels of xmcertainty in the measure-
ments used to estimate the fan noise levels. Fan noise on gasoline-
powered trucks tends to be higher than on diesel-powered trucks
because the greater heat rejection of gasoline engines requires rr-.o/. •=
cooling air flow. Neither cab type aor engine power appear to have a
significant effect of diesel-powered truck fan noise.
The control of fan noise must be viewed in terms of total eooli .-.g"
system design. Some noise reduction can be achieved by modifying
the radiator, the shutters, the fan sbroud, and, of course, i:bc f.i
itself. Data presently available to ONAC are inadquate to quantify
the exact relations between radiator size, heat transfer coefficient.,
and fan noise.
Radiator design is closely related to fan performance and nois«.,
Radiators designed with low airflow requirements allow the use ot
slower turning and, thus, quieter fans. The amount of noise reduction
achievable through modifications to the radiator depends on the initial
design, but even well-designed cooling systems can often be quieted
by 2 to 3 dB(A) through modifications to radiator design (Reference 7/,
5-7
-------
Ul
I
00
80
75
7O
65
o
O <
O
•
i
I Range of Confidence for
±0.5
•
<
0
i-.
<
.
_
r c
t
<
i
)
•
Y
OT
v without Enclosure
^ with Enclosure
u QT with
-
Partial Enck
jsure
e
.
—
zoo
300 400
NET FLYWHEEL HORSEPOWER
500
Figure 5-3 Diesel Truck Fan Noise Levels as a Function of Engine Horsepower.
-------
rtj °»
5
_r
UJ
bJ
O
z
o
(O
75
70
|
O
>
o
»
200 300
NET FLYWHEEL HORSEPOWER
Figure 5-4 Gasoline-Fueled Truck Faa tfoise Jewels c.s a
Function of Engine Horsepower.
5-9
-------
Thermostatically controlled shutters are used on many trucks
to regulate air flow through the radiator. The primary purpose of
the shutters is to prevent cold water from overcooling the engine on
very cold days. Shutters significantly influence fan noise. When the
shutters are closed and air flow to the fan is substantially reduced,
the fan blades stall and generate more noise.
Shrader (Reference 7) reports a 5 dB(A) increase in fan noise
as a result of closed shutters. One manufacturer reported approxi-
mately a 2 to 3 dB(A) increase in total truck noise for his engine
line of models when shutters were closed. Several manufacturers
feel that shutters could be replaced by thermostats and bypass tubing.
The fan shroud, which ducts air from the radiator to the fan, is
important in maximizing fan effectiveness and preventing recircula-
tion of hot air back through the radiator. Shrouds that do not channel
this air smoothly into the fan can lead to stalled blade tips with an
attendant increase in noise. Shrader (Reference 7) claims that im-
proved shroud designs can produce a 3 to 5 dB(A) reduction in fan
noise levels.
The fan itself can often be changed to reduce noise. One
of the most effective changes is to increase fan diameter and
decrease fan speed. A 2- to 3-inch increase in fan diameter typically
allows a 3 to 5 dB(A) reduction in noise for a constant volume flow
rate. The extent to which fan diameter may be increased is limited
by the configuration of the radiator and essential structural members
of the truck.
5-10
-------
The Cab Over Engine (COE) tractor is particularly suitable for
a large, slow fan. Because of the large, blunt front on the COE,
the forward motion of the truck tends to develop a high pressure
rise in front of the radiator that supplements the flow created by
the fan. Using this type of cab and a large radiator with a frontal
area of 2, 000 square inches, Freightliner achieved a fan noise level
of 66 dB(A) (Reference 8). The fan, which is thermostatically
controlled, operates for about only l%of the time. For the remainder
of the time, the forward motion of the truck is able to force sufficient
cooling air through the radiator.
The data in Figures 5.3 and 5.4 indicate that most fans generate
less than 80 dB(A). Those that are noisier can be replaced by a slightly
different fan model and fan/engine speed ratio. Reduction of fan
noise to 75 dB(A) may require somewhat larger radiator cores and
larger, slower fans. Levels can be reduced to 65 dB(A) with larger
radiator cores, larger and slower fans, careful design of fan shrouds,
and a thermostatically controlled fan clutch that is phased with a
shutter thermostat to prevent fan operation while the shutters are
closed.
Intake
Air intake systems supply truck engines with the continuous flow
of clean air needed for fuel combustion. These systems can range
in size and complexity from a simple air filter mounted on top of a
carbureter to an external air filter with ducts leading to the engine
and a cab-mounted snorkel unit. Noise is generated by unsteady
5-11
-------
flow of air into engine cylinders. Supercharged engines with Rootes
blowers also exhibit tones associated with the blade-passage frequen-
cy of the blowers. Turbochargers tend to smooth flow irregularities
associated with cylinder charging.
Two DOT reports on exhaust systems (References 8, 9) include
studies of air intake systems on five diesel engines. The sound
levels are listed in Table 5-1. The DOT report also list the air
intake source levels when additional air filters are installed on these
engines. Source levels that have been measured for air intake sys-
tems on gasoline-fueled trucks are all less than 69 to 72 dB(A) at
50 feet.
Intake systems may be readily quieted by air filters. Hunt, et.
al. (1973) and DOT (1973) (References 8 and 9) report that the intake
systems they examined could in all cases be quieted to source levels
below 75 dB(A) and in some case to below 65 dB(A). It is expected
that no performance change in air intake systems will be needed to
achieve overall truck levels of 83 or 80 dB(A). To achieve overall
truck levels of 75 dB(A), for example, it may be necessary to add
silencers to some engines.
TABLE 5-1
AIR INTAKE SOURCE LEVELS
Air Intake Source
Engine Type hp Level at 50 Feet
[dB(A)j
Naturally aspirated, 4-stroke 250 82
Turbocharged, 4-stroke 350 70
Rootes Blower, 2-stroke 238 82
Turbocharged, 4-stroke 238 83
5-12
-------
Exhaust
Exhaust outlet noise emanates from the exhaust system term-
inus and is generated bythe pressure pulses of exhaust gases from the
engine. Shell-related exhaust noise consists of radiation From thr
external surfaces of the pipes and mufflers of the exhaust system.
It is generated by two mechanisms, the transmission and subsequent
radiation of engine vibration to the exhaust system and the trans-
mission of internal sound to the exterior of the pipe.
Hunt et al. (Reference 9 & 10 -) found that the source levels of
unmuffled outlet noise for diesel engines can range from 82 to
105 dB(A) at 50 feet. Exhaust shell noise is low enough that very
few trucks require modifications to this source to reach overall le-
vels of 83 dB(A). However, some modification is required to
achieve overall levels of 80 dB(A) and lower.
Noise control techniques for exhaust noise consist of muffling
exhaust outlet noise, using double-wall construction on pipes and muf-
flers to reduce radiation from exhaust line elements and incorporating
vibration-isolated clamps connecting the exhaust pipe to the engine
to reduce the engine vibration source of shell noise.
In selecting a muffler, the work the engine must expend on push-
ing exhaust gases out the exhaust port, with resulting degradation
of overall engine performance, should be considered.
Manufacturers are able to choose from among a wide variety
of mufflers, some of which provide low noise levels at no more cost
or higher back pressure than noisier mufflers. Mufflers are avail-
able to reduce the exhaust source levels of 6 cylinder, in-line turbo-
5-13
-------
charged diesel engines, naturally aspirated 4-stroke diesel engines,
and turbocharged 4-stroke V engines to 75 dB(A) with no apparent
cost increase.
The unmuffled source levels of popular 2-stroke engines are at
least 10 dB(A) higher than for other engines. Although apparently
no mufflers presently manufactured can reduce the source level of
these engines, say, to 75 dB(A), the available technology could enable
manufacturers to design such a muffler system, or combine present
designs into a dual configuration.
The anticipated method of reducing exhaust noise on 12-cylinder,
2-stroke diesel engines to overall levels of 83 or 80 dB(A) is to
use dual or series mufflers.
With the addition of turbochargers to diesel engines, which
reduce the unmuffled exhaust noise, noise reductions on the order
of 5 to 10 dB(A) have been reported. Thus, turbocharging greatly
increases the ease of obtaining overall truck noise level reductions.
Tire Noise
Truck tires generate noise by interacting with road surfaces.
Numerous factors affect tire noise, including pavement surface, tire
tread design, tire load, whether the pavement is wet or dry, and
vehicle speed. In a recent study for the Highway Research Board,
Rentz and Pope (Reference 11) compiled truck tire noise data from
seven sources and developed the following regression equation for
5-14
-------
A-weighted tire noise levels L at 50 feet:
L - B + 40 log 1 (£Q) + 10 log 1Q (|500) + 10 log 1Q (N)
Here B is a constant, the value of which depends on the tread pattern
and state of wear, V is the vehicle velocity (in mph), W is the
tire load (in Ibs) and N is the number of axles on the truck. When
this equation was used to predict tire noise associated with 47 loaded
tractor-trailer combinations, noise levels were found to be within
a mean error of 1. 3 dB(A)anda standard deviation of 2. 2 dB(A) com-
pared with measured data.
There are at least two techniques that may be used to control
tire noise: (1) substitute quiet tires noisy ones, and (2) design quiet
tires from the start. When considering substitution, based on pres-
ently available tires, it would be desirable to consider equipping
trucks entirely with ribbed tires. It should be noted, however, that
cross-lug tires are typically used on the drive wheels of tractor-
trailer trucks because of tractive requirements.
The design of tires that are significantly quieter than those how
being manufactured requires a technology base that is not now exist-
ent. Some efforts have been applied to developing new technology;
for example, tire manufacturers have found that by randomizing tread
patterns, pure tones can be spread in the frequency spectrum with
a concomitant reduction in community annoyance. However, funda-
mental noise-producing mechanisms have not been quantitatively
assessed.
5-15
-------
TOTAL TRUCK NOISE CONTROL
The component noise control measures described above may
be combined in a variety of ways to meet specified limits for
overall truck noise. (Tire noise control is not included in this dis-
cussion. ) In general, the noise control strategy is determined by
the source level of the noisiest and most difficult-to-control compon-
ent, usually the engine. Gasoline-fueled and diesel-fueled trucks
are discussed separately because of the difference in their engine
source levels.
The combinations of source levels suggested in this section for
achieving specified overall truck levels are intended to be represent-
ative of practical examples. In some cases, a manufacturer may
prefer to have one source level higher and another lower than sug-
gested. As a guarantee of the component levels, tolerances could
be placed on each component. For example, to ensure an 81 dB(A)
for the engine, the manufacturer would design the engine for a 79
dB(A) level with a 2 dB(A) tolerance. Likewise, the expected toler-
ances for the fan and the exhaust might be 2 dB(A). These tolerances
must be subtracted from the maximum listed values.
5-16
-------
Diesel-Fueled Trucks
Present production medium and heavy duty diesel trucks display
the following ranges of measured source levels (in dB(A)):
Engine Fan Exhaust
76-85 75-85 75-85
All manufacturers are currently able to reach an 86 dB(A) overall
level with off-the-shelf hardware. They have apparently concentrated
on quieting their noisiest production trucks first. Thus, trucks
having engines with source levels of 80 to 85 dB(A) have quieter fans
and exhaust systems than trucks with quieter engines.
Table 5-2 shows one combination of source levels that will
yield a production line truck that generates an overall noise level
of less than 83 dB(A). More than 30% of trucks presently being pro-
duced already generate noise levels less than 83 dB(A). Of those
trucks not meeting this level some will require only a few modifica-
tions, while others will require engine or underhood treatment.
Nevertheless, all manufacturers could produce trucks that would
achieve this level with all engine types, using off-the-shelf hardware.
This may require that such trucks, depending on the model, be
TABLE 5.2
COMPONENT SOURCE LEVELS FOR AN 83 dB(A)
OVERALL TRUCK NOISE LEVEL
Component
Engine
Fan
Exhaust
All others
Noise Level, dB(A
x.
-------
engine noise control packages.
The primary design problem will likely be the cooling fan> Truck
manufacturers may purchase quieter fans from vendors, but fan noise
is influenced by the operating environment as much as by fan design.
However, manufacturers may elect to use larger, slower fans with
well-designed shrouds and replace radiator shutters with a bypass
tubing to achieve greater noise reduction.
Component source levels which will yield trucks whose overall
noise level is, for example, 80 dB(A), are shown in Table 5-3. Vir-
tually all trucks produced today will require quieting attention to meet
this level. Engine noise will be a prime target for quieting. The quieter
diesel engines, which are used in about 23% of the trucks currently
produced, will require covers or quieting kits to reduce their noise,
while the noisier diesel engines, which are used in about i2% of present
production trucks, will require a partial engine enclosure, entailing
redesign of the cab, or redesign of the engine itself to reduce struc-
tural and combustion noise. Alternatively, truck manufacturers may
elect to use one of the quieter engines already available.
To obtain an 80 dB(A) overall level, manufacturers will also
have to quiet other components. They may be able to compensate
TABLE 5-3
COMPONENT SOURCE LEVEL COMBINATIONS FOR
AN 80 dB(A) OVERALL TRUCK NOISE LEVEL
Component Noise Level, dB(A)
Engine
Fan
Exhaust
All Others
for a slightly too noisy engine by lowering exhaust levels more.
5-18
-------
Table 5-4 shows a combination of component levels that will
produce a truck with an overall noise level of 75 dB(A). To achieve
this level, most trucks will require some type of engine enclosure
built into the cab. In addition, other components will require treat-
ment with the best available technology.
TABLE 5-4
COMPONENTS SOURCE LEVELS FOR A 75 dB(A)
OVERALL TRUCK NOISE LEVEL
Component Noise Level, dB(A)
Engine ^ 70 ^
Fan =^65 \ ^. 75
Exhaust ^-68 /
All Others ^ 70 )
Gasoline-Fueled Trucks
The source levels measured in gasoline trucks are [in dB(A)]:
Engine Fan Exhaust
75-77 80-85 80
Table 5-5 lists a set of component source levels that will pro-
duce a truck with an overall noise level of 83 dB(A). Noise control
to meet this level will consist primarily of quieting fan noise by using
a larger, slower fan and incorporating a better exhaust system.
TABLE 5-5
POSSIBLE COMPONENT SOURCE LEVEL COMBINATIONS
FOR SPECIFIED OVERALL TRUCK NOISE LEVELS
83 dB(A)
Component Noise Level, dB(A)
Engine
Fan •£ 80 V *=. 83
Exhaust
All Others
5-19
-------
A Hat of component source levels that will permit a truck to
meet an overall level of ttOdtt(A) IH given In Tnhlo 5.0. Mfinurw-
turers will have no significant problems in achieving engine and ex-
haust noise levels. They will have to improve the cooling system
by using a larger, slower fan, possibly a thermostatic control to
eliminate shutters or control their opening, and possibly a larger
radiator.
TABLE 5-6
POSSIBLE COMPONENT SOURCE LEVEL COMBINATIONS FOR
SPECIFIED OVERALL TRUCK NOISE LEVELS
80 dB(A)
Component Noise Level. dB(A)
Engine
Fan
Exhaust
All Others
Table 5-7 lists component source levels that will give an overall
truck noise level of 75 dB(A). Manufacturers will probably be able
to quiet engine noise by means of engine covers and quieting kits;
e.g., under-hood cab treatment, side shields, and recirculation
panels.
TABLE 5-7
POSSIBLE COMPONENT SOURCE LEVEL COMBINATIONS FOR
SPECIFIED OVERALL TRUCK NOISE LEVELS
75dB(A)
Component Noise Level, dB(A)
Engine
Fan
Exhaust
All Others
5-20
-------
REFERENCES FOR SECTION 5
1. Tiede, D. D. and Kubele, D. F. "Diesel Engine Noise Reduction
by Combustion and Structural Modifications, " Society of Automo-
tive Engineers, Paper No. 730245, 1973.
2. Priede, T. et al. "Combustion-Induced Noise in Diesel Engines, "
presented at the General Meeting of the Institute of Marine En-
gineers. 1967.
3. Ungar, E. E. and Ross, D. "Vibrations and Noise Due to
Piston-Slap in Reciprocating Machinery, " J. Sound Vib. 2, 1965.
4. Jenkins, S. H. and Kuehner, H. K. "Diesel Engine Noise Reduc-
tion Hardware for Vehicle Noise Control, " Society of Automotive
Engineers, Paper No. 730581, 1973.
5. Thien, G. E. "The Use of Specially Designed Covers and Shields
to Reduce Diesel Engine Noise, " Society of Automotive Engin-
eers, Paper No. 730244, 1973.
6. Averill, D. and Patterson, W. "The Design of a Cost-Effective
Quiet Diesel Truck, " Society of Automotive Engineers, Paper
No. 730714, 1973.
7. Shrader, J. T. "Cooling System Noise Reduction on Heavy Duty
Diesel Trucks," Noise-Con 73 Proceedings, pp. 68-73, 1973.
8. Bender, E. K. and Patterson, W. "Diagnosis and Noise Control
of Freightliner Trucks," BBN Report No. 2317c (Freight-
liner Report No. 3), 1974.
9. Hunt, R. et al. "Truck Noise VIA. Diesel Exhaust and Air
Intake Noise," DOT-TSC-OST-73-12, PB222642, 1973.
10. DOT. "Truck Noise VIB. A Baseline Study of Parameters
Affecting Diesel Engine Intake and Exhaust Silencer Design" (in
draft), 1973.
11. Rentz, P. and Pope, L. "Description and Control of Motor
Vehicle Noise Sources, " BBN Report No. 2739, 1974.
5-21
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SECTION 6
HEALTH AND WELFARE
INTRODUCTION
Section 2(b) of the Noise Control Act of 1972 states: "The
Congress declares that it is the policy of the United States to promote
an environment for all Americans free from noise that jeopardizes
their health or welfare...." Consistent with this policy and as part of
the regulation development process, two analyses have been conducted
to evaluate the effects of new truck noise on public health and welfare.
In one analysis, discussed here, the effects on the American pop-
ulation of new truck operating rules, together with the effects of three
different levels of new production truck noise were assessed. This
study is a statistical analysis that considers the impact of truck noise
on the total national population.
In a second analysis, environmental situations defined by scenarios
were evaluated to estimate truck noise levels that might allow human
activities to be carried on at various activity sites without evocation
of annoyance by intruding truck noise. These levels can then be com-
pared with different new truck noise levels to assess the type of environ-
mental situations resulting.
Both analyses use the same basic information. The principal dif-
ference is in the presentation of the results. The statistical model
considers the change in the average day-night noise energy level, Ldn.
The individual case model considers the maximum noise level intrusion
due to single events of truck passby noise.
6-1
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EFFECT OF NEW TRUCK NOISE LEVELS ON PUBLIC HEALTH AND
WELFARE "IN THE LARGE"
Introduction
In this section the effects of differing new production truck noise
levels on the health and welfare of the United States population are an-
alyzed. The approach taken for this analysis is statistical in that an
effort is made to determine the order of magnitude of the population
that may be affected by the proposed action. Thus, there may exist
some uncertainties with respect to individual cases or situations.
However, such effects cannot be completely accounted for; thus the
necessity to employ a statistical approach.
The phrase "public health and welfare effects, " as used herein,
includes personal comfort and well-being as well as the absence of
clinical symptoms (e.g., hearing loss).
To perform the analysis presented in this section, a noise meas-
ure is utilized that condenses the information contained in the noise
environment into a simple indicator of quantity and quality of noise
which, in EPA's judgment, correlates well with the overall long-term
effects of noise on the public health and welfare. This measure was
developed as a result of the Noise Control Act of 1972, which required
that EPA present information on noise levels that are "requisite to
protect the public health and welfare with an adequate margin of
safety. "
In accordance with this directive, EPA has selected those noise
measures believed most useful for describing environmental noise
and its effect on people, independent of the source of the noise. That
6-2
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is, the noise produced, whether by motor vehicles, aircraft, or in-
dustrial facilities, is evaluated on the basis of a common measure
of noise. Further, the magnitude of environmental noise, as de-
scribed by this measure that EPA considers desirable from a long-
term view of public health and welfare, has been selected for a variety
of occupied space and land uses.
In the following sections, the measures to be used in
evaluating environmental noise, the numerical values for those levels
EPA will consider in assessing impact, and a general methodology
for quantifying the noise impact of any noise-producing system being
added to the environment, or the impact of a change in an existing
noise-producing system are addressed. A specific application of
this methodology to assess the effects of the proposed regulations
on motor vehicle noise is also developed.
Definition of Leg and Ldn
Environmental noise is defined in the Noise Control Act of 1972
as the "intensity, duration, and the character of sounds from all
sources." A measure for quantifying environmental noise must not
only evaluate these factors, but must also correlate well with the
various modes of response of humans to noise and be simple to meas-
ure (or estimate).
EPA has chosen the equivalent A-weighted sound level in decibels
as its general measure for environmental noise (Reference 1). The
6-3
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general symbol for equivalent level is Leq, and its basic definition
is:
•» —«*• - "
where t%- t, is the interval of time over which the levels are eval-
uated, p(t) is the time varying sound pressure of the noise, and p
o
is a reference pressure, standardized at 20 micropascal. When
expressed in terms of A-weighted sound level, LA, the equivalent
A-weighted sound level, Leq, may be defined as:
*i-*.
There are two time intervals of interest in the use of Leq for impact
assessment. The smallest interval of interest for vehicle noise on
highways is one hour, often the "design hour" of a day. The primary
interval of interest for residential and similar land uses is a 24-hour
period, with a weighting applied to nighttime noise levels to account
for the increased sensitivity of people associated with the decrease
in background noise levels at night. This 24-hour weighted equivalent
level is called the Day-Night Equivalent Level, and is symbolized
as Ldn. The basic definition of Ldn in terms of the A-weighted
sound level is:
4+
/* AA
" A ?A&
^V<* f **)/*
o • *t + 110 -/t
^o-too »*oo
or,
(6.3)
* '* 44.
where Ld is the equivalent level, obtained between 7 a.m. and
6-4
-------
10 p.m. and Ln is the equivalent level obtained between 10 p.m.
and 7 a. m. of the following day.
Assessment of Impact due to Environmental Noise
The underlying concept for noise impact assessment In this anal-
ysis is to compare the change in expected impact, in terms of number
of people involved, to the change expected in the noise environment.
Three fundamental components are involved in the analysis: (I) def-
inition of initial acoustical environment, (2) definition of final acous-
tical environment, (3) relationship between any specified noise envir-
onment and expected human impact.
The first two components of the assessment are entirely site or
system specific, relating to either estimates or measurement of the
environmental noise before and after the action being considered.
The same approach is used, conceptually, whether one is examining
one single house near one proposed road or all the houses near the
entire national highway system. The methodology for estimating the
noise environment will vary widely with the scope and type of prob-
lem, but the concept remains the same.
In contrast to the widely varying possible methodologies for esti-
mating the noise environment in each case, the relationships to
human response can be quantified by a single methodology for each
site or noise producing system considered in terms of the number of
people in occupied places exposed to noise of a specified magnitude.
This is not to say that individuals have the same susceptibility to
noise; they do not. Even groups of people may vary in response,
6-5
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depending on previous exposure, age, socio-economic status, polit-
ical cohesiveness, and other social variables, tn the aggregate,
however, for residential locations the average response of groups of
people is quite stably related to cumulative noise exposure as ex-
pressed in a measure such as Ldn. The response to be used is the
general adverse reaction of people to noise. This response is a com-
bination of such factors as speech interference, sleep interference,
desire for a tranquil environment, and the ability to use telephones,
radio, and television satisfactorily. The measure of this response
is related to the percent of people in a population that would be ex-
pected to indicate a high annoyance to noise at a specified level of
noise exposure.
For schools, offices, and similar spaces in which criteria for
speech communication or risk of damage to hearing are of primary
concern, the same averaging process can be used to estimate the
potential response of people as a group, again ignoring the individ-
ual variations among people. In both instances, then, residential
(or like)areas andnonresidential, howthe average response of people
varies with environmental noise exposure is considered,
A detailed discussion of the relationships between noise and human
response is provided in several published EPA documents. For ex-
ample, the different forms of response to noise such as hearing
damage, speech or other activity interference, and annoyance
are related to Leq and Ldn in the EPA Levels Document (Reference
1). For the purposes of this study, two sets of criteria have
been adapted from these EPA documents. It will be considered
6-6
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that if the levels identified in the previous document are met, no
impact exists.
The level of environmental noise identified as requisite to protect
the public health and welfare with reference to speech communication
indoors is a day-night sound level (Ldn) of 45 dB (Reference 1). A
noise environment having this level should provide, on the average,
100% speech intelligibility for all types of speech material, and have
a calculated articulation index of 1. 0 (Reference 2).
The intelligibility for sentences (first presentation to listeners)
drops to 90% when the level of the noise environment is increased by
approximately 19 dB above the identified level, and to 50% when the
level is increased by approximately 24 dB. The intelligibility for
sentences (known to listeners) drops to 90% when the level is
increased by approximately 22 dB above the identified level, and to
50% when the level is increased by approximately 26 dB (Reference
1). Thus, considering that normal conversation contains a mixture
of both types of material, some new and some familiar, it is clear
that when the level of environmental noise is increased by more
than 20 dB above the identified level, the intelligibility of conver-
sational speech deteriorates rapidly with each decibel of increase.
For this reason, a level which is 20 dB above the identified level
is considered to result in 100% impact on the people who are exposed.
For environmental noise levels which are intermediate between 0
and 20 dB above the identified level, the impact is assumed to
6-7
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vary linearly with level; i0e., a 5 dB excess constitutes a 25% impact
and a 10 dB excess constitutes a 50% impact.
A similar conclusion can be drawn from the community reaction
and annoyance data containedin Appendix D of Reference 1. The com-
munity reaction data show that the expected reaction to an identifiable
source of intruding noise changes from "none" to "vigorous" when
the day-night sound level increases from 5 dB below the level existing
without the presence of the intruding noise to 19. 5 dB above the pre-
intrusion level. Thus, 20 dB is a reasonable value to associate with
a change from 0 to 100% impact. Such a change in level would
increase the percentage of the population which is highly annoyed
by 40% of the total exposed population (Reference 8).
For convenience of calculation, these percentages may be ex-
pressed as fractional impact (FI). An FI of 1 represents an impact
of 100%, in accordance with the following formula:
FI - 0. 05 (L-Lc) for L ?Lc
(6.4)
FI = 0 for La Lc
where L is the appropriate Leq for the environmental noise and Lc
is the appropriate identified criterion level. (Note that FI can exceed
unity.)
The appropriate identified criterion level for use in calculating
fractional impact is obtained from Table 4 of Reference 1. For
the analysis of the impact of the noise of motor vehicles on people
living in residential areas, the appropriate identified level is an
Ldn of 55 dB, which exists outdoors. For other analyses concerned
6-8
-------
with office buildings and other types of spaces when indoor speech
communication is the principal factor of concern, the appropriate
identified criterion level is an Ldn of 45 dB (indoors), which is trans-
lated to an outdoor level by using a sound level reduction appropriate
to the type of structure.
Data on the reduction of noise afforded by a range of residential
structures are available (Reference 3). These data indicate that
houses can be approximately categorized into "warm climate" and
"cold climate" types. Additionally, data are available for typical
open-window and closed-window conditions. These data indicate that
the sound level reduction provided by buildings within a given com-
munity has a wide range due to differences in the use of materials,
building techniques, and individual building plans. Nevertheless,
for planning purposes, the typical reduction in sound level from out-
side to inside a house can be summarized as shown in Table 6-1.
The approximate national average "window open" condition corre-
sponds to an opening of 2 square feet and a room absorption of 300
sabins (typical average of bedrooms and living rooms). This window
open condition has been assumed here in estimating conservative
values of the sound levels inside dwelling units which result from
outdoor noise.
The final notion to be considered is the manner in which the
number of people affected by environmental noise is introduced into
the analysis. The magnitude of total impact associated with a defined
6-9
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level of environmental noise may be assessed by multiplying the
number of people exposed to that level of environmental noise by the
fractional impact associated with this level of the environmental noise
as follows:
Peq = (FI) P (6.5)
where Peq is the magnitude of the impact on the population and is
numerically equal to the equivalent number of people all of which would
have a fractional impact equal to unity (100%) impacted). FI is the
fractional impact for • the defined level of environmental noise and
P is the population affected by this level of environmental noise,.
TABLE 6-1
SOUND LEVEL REDUCTION DUE TO HOUSES* IN
WARM AND COLD CLIMATES, WITH WINDOWS
OPEN AND CLOSED
(Reference 3)
Windows Windows
Open Closed
Warm Climate 12 dB 24 dB
Cold Climate 17 dB 27 dB
Approximate National Average 15 dB 25 dB
*Attenuation of outdoor noise by exterior shell of the house.
Where knowledge of structure indicates a difference in noise
reduction from these values, the criterion level may be altered
accordingly.
When assessing the total impact of a given noise source or an
assemblage of noise sources, the levels of environmental noise asso-
6-10
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elated with the source(s) decrease as the distance between the source
and receiver increase. In this case, the magnitude of the total impact
may be computed by determining the number of people exposed at
each level, and summing the resulting impact. The total impact is
given by the following formula:
(6.6)
4
i\
where Fl. is the fractional impact associated with the i level and
ii ,
P( is the population associated with i level.
The change in impact associated with an action leading to noise
reduction, or change in population through a change in land use, may
be assessed by comparing the magnitude of the impacts for the "be-
fore" and "after" conditions. One useful measure is the percent
reduction in impact (M, which is calculated from the following
expression:
(P eq (before) - Peg (After))
A :-- 100 f eq (before) (6.7)
Note that the percentage change may be positive or negative de-
pending upon whether the impact decreases (positive percentage
reduction) or the impact increases (negative percentage reduction).
Thus, a 100 percent positive change in impact means that the
environmental noise has been reduced such that none of the population
is exposed to noise levels in excess of the identified levels.
In order to place this concept in perspective, an example is first
considered. In the EPA study, "Population Distribution of the
United States as a Function of Outdoor Noise Level" (Reference 9),
an estimate is provided for the number of people in the United
6-11
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States exposed to various levels of urban noise. The above concepts
can be used to illustrate the current impact of this exposure, and
then to assess the change in impact if all noise sources were reduced
5, 10, or 15 decibels. In the following computation, using the data
taken from this study, Pi is defined as the population between succes-
sive 5 decibel increments of Ldn. This population is assigned an ex-
posure Ldn midway between the appropriate successive Ldn levels.
(•"or this example, the identified criteria level is an Ldn of 55 dB
measured outdoors.
The result, provided in Table 6.2, shows that a 5 dB noise
reduction results in a 55% reduction in impact, a 10 dB noise re-
duction results in an 85% reduction in impact and a 15 dB noise
reduction results in a 96% reduction in impact.
The impact assessment procedure maybe summarized by the fol-
lowing steps:
1. Estimate the Leq or Ldn produced by the noise source system
as a function of space over the area of interest.
2. Define sub-areas of equal Leq or Ldn, in increments of 5
decibels, for all land use areas.
3. Define the population, P, , associated with each of the sub-
areas of step 2.
4. Calculate the FI, values for each Ldn ' and Leq'', obtained
in step 2.
5. Calculate FI,: x P, for each sub-area in step 2.
6. Obtain the equivalent impacted population for the condition
6-12
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existing before the change being evaluated,
Peqt. = FI,- x P<-,
by summing the individual contributions of step 5.
7. Repeat steps 1-6 for the noise environment existing over the
area of interest after the change being evaluated takes place,
thus obtaining PeqA. (Note that the sub-areas defined here
will not in general be congruent with those of step 2 above.)
8. Obtain the percent reduction in impact from
(6.8)
Application of Assessment Technique to New Truck Regulation
The methodology presented in the previous section can be
directly applied for assessing the effects of motor carrier operating
rules, together with the effects on the United States population
of different noise levels for new production trucks. The following
information provides a quantitative comparison of the noise reduction
and change in the equivalent number of people impacted by vehicle
noise in the urban areas of the United States.
Urban Traffic. In performing this analysis, use has been made of
the highway noise model presented in the Highway Research Board
Design Guide (HRBDG). Furthermore, the following assumptions
have been made for the urban traffic situation:
1. The baseline conditions for trucks will exist as of October
1974, as described in the noise emission standards for motor
carriers in interstate commerce proposed by EPA under
6-13
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Section 18 of the Noise Control Act (38 FR 20102 July 27,
1973). Carrier operating standards require that all medium
and heavy duty trucks over 10, 000 pounds gross vehicle weight
rating (GVWR) not exceed the level of 86 dB(A) under any
conditions of operation when traveling at speeds less than
35 mph. In the urban environment, since the average speed
through urban streets is 27 mph (Reference 1), this baseline
assumption is a suitable starting point for the determination
of noise level changes resulting from a new truck regulation.
2. The vehicle mixture is assumed to be 1% heavy duty trucks,
6% medium duty trucks and 93% automobiles (Reference 8).
3. The population density in the vicinity of urban roads for noise
impact assessment is that recently reported by EPA (Refer-
ence 9).
4. State and city noise regulations becoming effective during
the 1975 model year will force a 4 dB reduction in the noise
produced by new production automobiles. The 4 dB reduction
predicted to occur for automobiles and the expected use
of quiet tires are estimates based on current trends in
local and Federal noise ordinances. At this time, it is not
known if such events will actually occur.
Freeway Traffic
This analysis has been performed in terms of constant speed
(55 mph) cruise on level ground, and has made use of actual noise
reductions observed during cruise conditions. The data used are those
presented in HRBDG volume 5, page 11, table 2. The actual net
6-14
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en
I
M
U1
TABLE 6-2
ESTIMATE OF THE IMPACT OF SUCCESSIVE REDUCTION OF ALL URBAN NOISE SOURCES IN
5-DECIBEL INCREMENTS
Current Conditions
Population
Ldn e>:?ossd to PI
j ._, * higher L^n. millions
O *3 _f 1 -I _f Nj.il ^
ulllions
55 93.4 34.4
60 59.0 34.7
65 24.3 17.4
70 6.9 5.6
75 1.3 1.2
80 0.1 0.1
t
l
Total Equivalent People
Impacted
Percent Reduction in
Impact
Ldn N°i-se Reduction in Decibels
0
FI± FliPi
millions
0.125 4.3
0.375 13.0
0.525 10.9
0.875 4.9
1.125 1.4
1.375 0.1
34.6
0
5
Fli Fl4.Pl
millions
0 0
0.125 4.3
0.375 6.5
0.625 3.5
0.875 1.1
1.125 0.1
15.5
55
1
10
Fli FI.;Pi
millions
0 0
0 0
0.125 2.2
0.375 2.1
0.625 0.8
0.976 0.1
5.2
!
85
15
i
1 FI± FIipi
! - millions
0 0
0 0
0 0
0.125 0.7
0.375 0.5
0.625 0.1
1.3
96
-------
noise reduction during SAE J366 test is greater than the net
noise reduction during cruise due to the effect of tire noise at high
speeds.
For this analysis, the following assumptions were made:
1. A tire noise level of 77 dB(A)when measured at a cruise speed
of 55 mph and at a distance 50 feet away from the vehicle. An
UHHumptlon was made that rroHH-rib Lircn could for forced
out of use as a result of increasingly HO vert; hi'/h Hpocd not HO
standards being instituted by EPA under authorization of
section 18 of the Noise Control Act. This assumption of the
future extensive use of straight rib tires further supoorts the
choice of a tire noise level of 77 dB(A) at high speeds.
2. The mixture of vehicles is 10% trucks and 90% automobiles
(HRBDG).
3. There are 8,000 miles of freeways throughout the United States
in urban areas (Federal Highway Administration 1972
Highway Needs).
4. Since there exist very little data concerning the population den-
sity around highways, the average population density around
urban highways is assumed equal to that found in urban areas
for the nation as a whole. The 1970 census data indicated
that the average population density in urban areas for the
nation as a whole is 4, 950 people per square mile; thus, the
number chosenforthe present analysis is 5,000 people/square
mile. Furthermore, if the population distribution, around high-
ways is assumed homogenous, it is estimated that there are
6-16
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40 million people (8, 000 x 5, 000) presently living within 1/2
mile of (each side) an urban freeway.
5. A basic highway is level and has six lanes of traffic. For the
purpose of calculating attenuation of noise on the highway,
it is assumed that the typical house is on a lot 100 feet long,
50 foot wide, and 70 fool from tho nearest lane of the freeway.
6. Do sign hour is predicated on l.nilTir How of 7. 200 vohiHoH
per hour traveling at an average .speed of 55 rnph.
7. As of October 1975, Interstate Motor Carrier operating rules
will permit noise levels from medium and heavy duty trucks
to be no greater than 90 dB(A) at speeds greater than 35
mph, measured at 50 feet from the centerline of the vehicle
path. The data points used from which further extrapolations
may be made are at 83, 80 and 75 dB.
8. For purposes of health impact assessments three models
have been developed with varying effective dates. These are:
Model 1- New trucks of over 10,000 Ib GVWR will be re-
quired not to exceed the following noise levels
(in dB(A)) after October of the year indicated:
83 1976
80 1980
75 1982
and the U. S.E.P.A. Interstate Motor Carrier
standards, as proposed, are in effect.
6-17
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Model 2 - Same as Model 1 with the following dates:
83 1976
80 1977
75 1980
Model 3 - Same as Model 1, with effective dates used to separate
gas engine and diesel engine powered trucks:
Gas Diesel
80 83 1976
80 83 1977
75 80 1980
75 75 1982
The following analysis considers operations under three condi-
tions: urban freeways only, urban streets only, and the aggregate of
•
the two. The analysis derives the change in Ldn, for each condition,
for various years between 1974 and 1992, the number of people im-
pacted at levels of Ldn of 55 and higher, and the change in impact
for the various strategies.
The results of the analysis are summarized in the attached
tables:
Table 6-3 - Change in Ldn for the baseline case and the
three models as a function of time, relative
to 1974 noise levels.
Table 6-4 - Number of equivalent noise impacted people
for the baseline case and the three models
as a function of time.
6-18
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Table 6-5 - Percentage change in number of equivalent
noise impacted people for the baseline case
and the three models relative to 1974.
The impact estimates indicate that MntlolH 1 mxl 'i hnvc llx-
results, whereas Model 2 accelerates the reduction in impact by
approximately 2 years. The percent reduction in impact from Free-
way traffic is slightly greater than that for urban streets (63 or 57%).
The estimated percentage reduction for the combined impact of traf-
fic on urban streets is 58%, reflecting that the preponderance of the
expected impact is attributable to traffic on urban streets.
Further analysis indicates that the remaining estimated impact
from traffic on urban streets in 1992 apportioned to truck .sources
is approximately as follows:
Medium duty trucks 37%
Heavy duty trucks 6%
To achieve an additional significant reduction in impact requires
further reduction of the levels for medium duty trucks and automo-
biles. For example, if Doth were reduced by an additional 6 dB, the
above percentages would be decreased by a factor of 4 to 9. 2% for
medium duty trucks and 14, 3% for automobiles. This change would
reduce the day/night sound level resulting from traffic on urban
streets by approximately 5.3 dB. This decrease in level would
reduce the estimated equivalent number of people impacted after the
regulation is fully effective from 15. 9 million to 5 million, a reduction
of over 86% from the 1974 baseline condition.
6-19
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Table 6.3
Reduction in Day-Night Level in Decibels Relative to 1974
Values, as a Function of Years
Item
Freeways
Operating rules and new autos
Model 1
Model 2
Model 3
Urban streets
Operating rules and new autos
Model l
Model 2
Model 3 ...
1976
2.4
2.4
2.4
2.4
0.7
0.7
0.7
0.7
1980
2.4
3.6
4.4
3.6
1.2
1 5
1.8
1.5
Year
1982
2.4
5.0
6.2
5.0
1.4
2.1
2.5
2.1
1990
2.4
8.4
8.6
8.4
2.0
4.9
5.0
4.9
" —
1992
2 4
8 fi
8 6
8 fi
2 n
*• . VJ
50
. 5
5c
• ->
S "\
6-20
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Table 6.4
Noise Impacted People
(In millions)
Item
Operating rule and new
autos only
Freewav ...............
Total
Model 1
Total
Model 2
Freeway ...............
Total
Model 3
T?TO£»vjav . .............
Total
1974
Z.7
34.6
37.3
2.7
34.6
37.3
2.7
34.6
37.3
2.7
34.6
37.3
1976
2.1
31.5
33.6
2. 1
31.5
33.6
2. 1
31.5
33.6
2 1
31. 5
33. 6
Yea
1980
2.1
29.4
31.5
1.8
28.0
29.8
1.7
27.0
28.7
1 8
28. 0
29 .8
r
1982
2.1
28.4
30.5
1.6
25.6
27.2
1.4
23.2
24.6
1 6
25.6
27.2
1990
2.1
2fi 0
?a i
i.l
15.9
17.0
1.0
14.9
15.9
1. 1
15.9
17.0
1992
2.1
?fi n
?8 1
1.0
14.9
15.9
1.0
13.8
14.8
1.0
14.9
15.9
6-21
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Table 6.5
Percent Reduction in Equivalent Noise Impacted Population Relative
to 1974 Baseline
Item
Year
1976
1980
1982
1990
1992
Freeway Only
Operating rules and new autos
only 22
Model 1 22
Model 2 22
Model 3 22
Urban Streets Only
Operating rules and new autos
only 9
Model 1 9
Model 2 9
Model 3 9
Total
Operating rules and new
autos only 10
Model 1 10
Model 2 10
Model 3 10
22
33
37
33
15
19
22
19
16
20
23
17
22
41
48
41
18
26
33
26
18
27
34
27
22
59
63
59
25
54
57
54
25
54
57
59
22
63
63
63
25
57
60
57
25
57
60
57
6-22
-------
EFFECT OF NEW TRUCK NOISE LEVELS ON PUBLIC HEALTH AND
WELFARE "IN INDIVIDUAL CASES"
This section considers the public health and welfare in individual
cases, the descriptions of the environmental situation models studied,
a discussion of the basic equation derived for analysis purposes, and
the presentation of the results obtained from analysis of the environ-
mental situations described,
Description of Environmental Situations Studied
For the purpose of this model, an environmental situation was
defined as follows: "An environmental situation is a common every-
day activity at which a human being spends considerable time and in
which intrusive noise of sufficient magnitude would evoke a feeling
of annoyance. " Since this definition of an environmental situation is
broad in nature, human activities and sites where human activity occurs
were selected to typify those environmental situations thought most
prevalent.
The three broad categories of human activity selected were
(1) normal conversation, (2) thought process and (3) asleep. For
each activity category, additional definitions are made below to qualify
the conditions and to set quantitative guidelines for the study.
Definitions were selected with the intent to limit the number of
environmental situations investigated but not to exclude nor com-
promise conditions highly germane to the model.
In the normal conversation category, the model was limited
to the passby interference of trucknoise on normal conversation. Nor-
6-23
-------
mal conversation was defined as an activity in which people could com-
municate at a comfortable voice level or hear television or radio sound
at a volume setting that would be comfortable in the absence of intrusive
noise. A level of 60 dB(A) was selected as an acceptable ambient speech
level for normal conversation indoors or outdoors in the absence of in-
trusive noise. The 60 dB(A) level selected was based on (1) actual
measurement, in a typical living room, during television listening at
a comfortable volume setting and (2) analytical calculations of the acous-
tic energy in a typical living room due to speech sound power levels
(Reference 4).
In the thought process category, the model was limited to the
influence of noise on reading, writing or studying. A level of 45 dB(A)
was selected as the acceptable ambient indoor level during the perform-
ance of any or all of these activities. The rationale for choice of the
45 dB(A) level is its common selection as that level which will permit
uninterrupted thought activity due to intrusive noise in a quiet office
(References 5 and 6). A second level, that of 51 dB(A), was selected
as the outdoor ambient level to comfortably perform outdoor thinking.
The rationale for this selection is based on the fact that outdoor ambient
noise levels are typically higher than interior ambient noise levels (Ref-
erence 7).
In the asleep category, the model was limited to the passby in-
fluence of truck noise on sleeping. A level of 40 dB(A) was selected
as that occurring in a typical urban bedroom. A level of 44 dB(A) was
selected as that representative of a typical outdoor nighttime ambient
level (Reference 7).
6-24
-------
The five categories selected for sites where human activity
enactment occurs were (1) an apartment interior, (2) a corner room
interior of a frame house, (3) an office interior, (4) an outdoors
residential location, and (5) an urban sidewalk location.
For the apartment interior site a room, with height to width to
length dimensions of 8 ft to 15 ft to 20 ft, was selected as representa-
tive of a typical medium sized apartment. Further, it was assumed that
the apartment contained a single window (closed and airtight) in a
wall exposed to the exterior and subject to the incident intrusive noise.
Other architectural-acoustic descriptions of the apartment interior site
appear in Appendix B.
The frame house (corner room) interior site description
was selected to duplicate most of the dimensions and acoustical char-
acteristics of the apartment interior with the added condition that the
room contained two adjacent walls with (closed and airtight) windows
exposed to intrusive noise incident on the exterior windowed surfaces.
Appendix B contains more architectural-acoustic description of the
corner room in the frame house interior site.
The office interior site room size was maintained at the 8 ft
x 15 ft x 20 ft dimensions of the apartment interior site, but was
modeled to architectural-acoustic qualities thought representative
of a typical off ice. Appendix B contains additional information to further
define the architectural-acoustic description of the off ice interior site.
The outdoors residential site was defined as a generally open,
free-field area void of obstructions that might cause sound reflections.
6-25
-------
The urban sidewalk site, like the outdoors residential site,
was defined as a free field. However, this is a special environmental
situation in that it was assumed a person walking on a suburban side-
walk where the ambient level is 73 dB(A) would become annoyed, for
whatever reason, if the ambient is appreciably raised. The 73 dB(A)
level is that typical on an urban sidewalk (Reference 7).
Discussion of Equation Derived for Analysis
Having defined an environmental situation and several
categories of human activities and activity sites, it is necessary
to calculate the truck noise levels in dB(A) measured at 50 feet
from the truck which, if permitted, would raise, for a particular
human activity, the sound level at a selected activity site by a
specified level above the acceptable ambient level assumed to have
existed prior to the passage of the truck. To make these calcu-
lations, the typical environmental situation has been mathematically
modeled using standard acoustic concepts. The derivation of the
appropriate situational model equations, including the necessary
assumptions, are presented in Appendix A.
S.
<6'8)
Equation (6.8), which is identical to Equation (A. 33)
in Appendix A, gives the noise level do in dB(A) of a truck,
measured at a distance 1^ , whose passby will produce a noise
level £ dB(A) inside a particular room located at a distance from
/w
the specified truck operation. The transmission and absorption
charactertics of the particular structure involved as well as the
6-26
-------
truck noise, which are all generally frequency dependent, are
jointly incorporated into the parameter q given by
A
= E<2p « E Tp_ Jop
P P
(6.9)
Here, the summation subscript p identified the p th
octave band, of interest to the study, while Ap and T p represent,
for the p th octave band, the interior absorption and structural
transmittance, respectively, for the particular activity site. Also,
A
Jop is the normalized A-weighted £jn octave band intensity component
of the noise spectrum for the specified truck operation.
As an example of the use of Equation (6.8), suppose that it
is desired to calculate the truck noise level in dB(A) measured at
50 feet which would preclude1 miliHtnnUal annoyance UHHoctntfd with
the disruption of a person's thought process during study iriBlde the
Apartment Interior activity site, as a result of low speed, high ac-
celeration truck operation along a road 50 feet away from the Apart-
ment.
It will be stipulated that an ambient noise level increase of
10 dB(A) above the acceptable ambient levels identified in this sec-
tion will initiate a substantial degree of annoyance for all of the
human activities defined. The 10 dB(A) ambient noise increase is
derived from Reference 3, where it is indicated that an increase
by this and even lesser amounts could cause annoyance. The 10
dB(A) might be considered as that amount of increase where sub-
stantial annoyance begins to occur. Thus, with this criteria, the noise
6-27
-------
level Inside the room .for 'the particular environmental situation being
considered; i.e., thinking in an Apartment 50 feet from the road, is
6 r -• acceptable ambient level +10 dB(A)
6 r = 45 + 10 = 55 dB(A)
From the interior description of the Apartment site given in
this section (and Appendix B), the sound absorption characteristics of
the Apartment activity space can be determined. The steps necessary
to calculate the total absorption for each octave band of interest for the
Apartment activity site are summarized in. Table C-l of Appendix C. In
Table C-l, values for the absorption coefficients, etc., for the various
site components were obtained from the references cited in Appendix B.
As shown in Table C-l, Column 6 provides octave band absorptions, in cm
absorption units, for the octave bands listed in Column 1.
From the wall structure description of the Apartment site given
in this section (and Appendix B), the transmission characteristics of the
Apartment structure can be determined. The steps necessary to cal-
culate the total transmittance for each octave band of interest for the
Apartment structure are summarized in Table D-l of Appendix D. In
Table D-l, values for the transmission coefficients fc were obtained
from the relation .
- /«/'<>
t = |0 (6.10)
where O£ is the transmission loss in decibels. Values for the various
transmission losses were obtained as follows: for the windows, the
best estimate of o^, is that obtained from the "mass law" (Reference 10).
6-28
-------
Thus, values of £g were obtained from the equation
6 = 10 log (1 + 1.366 x 10T3p2f2) (6.11)
t 10
where p is the surface density, Ibs/ft , of the window and f is the
frequency in Hz. For the walls, values of **t were obtained from
the reference cited in Appendix B.
The typical truck operation involved in this example environ-
mental situation is that of the low- speed, high-acceleration truck
operation that usually occurs when a truck at standstill begins move-
ment. The noise spectrum associated with this common truck opera-
tion is shown in Figure E-l of Appendix E. To facilitate its usage
in the analysis, the truck noise spectrum of Figure E-l was normal-
ized to a total sound intensity of one watt /cm . Table F-l of Appendix
F summarizes the steps taken in this normalization process for the
low speed, high acceleration truck operation noise spectrum.
The situational factors in Equation (6.9) can now be de-
termined. The steps taken to obtain these situational factors for
the environmental situation being presented are summarized in Table
G- 1 of Appendix G. From the data of column 5 of Table G. 2, it
is seen that the parameter can be calculated to be
q-q-. 000675
The noise level ( 9 ), measured at a distance (n0) of 50 feet,
6-29
-------
that the truck involved in this situational example can generate without
producing a noise level (6 ) of 65 dB(A) inside the Apartment located
at a distance ( r) of 50 feet from the road without causing substantial
annoyance to a person who is studying in the Apartment can thus be
calculated from Equation (6,8). Using the above information and the
value of from Equation (6.12), it follows that
6Q = 55 + 10 log! (5T?)( 00067^} = 87 dB(A) (6.13)
It should be emphasized that this allowable truck noise level for the
environmental situation studied is for a one occurence single truck
operation lasting over a relatively short; time duration,
The procedure used in the above example to illustrate how the
allowable truck noise level measured at 50 feet can be determined
for a particular environmental situation is outlined in step format
in Appendix H for use in calculating allowable truck noise levels in
other environmental situations.
Results for Environmental Situations Studied
The procedure outlined in Appendix H was used to determine
the truck noise levels at 50 feet which, if allowed, would cause sub-
stantial annoyance for each of a total of 113 environmental situations.
The environmental situations studied included various combinations
of activity sites, human activities, and distances from the road.
The results for these environmental situations are presented in Tables
6. 6 and 6. 7 for low speed, high acceleration and constant high speed
truck operation, respectively.
6-30
-------
TABLE 6.6
LOW SPEED, HIGH ACCELERATION TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Apartment Interior
Office Interior
Frame House
Interior
Apartment Interior
Office Interior
Frame House
Interior
Apartment Interior
Office Interior
Apartment Interior
Frame House
Interior
Office Interior
Apartment Interior
Frame House
Interior
at 50 Feet
Human Distance from to Preclude
Activity or Road Centerline Annoyance
Condition (ft) (dB(A))
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Thought
Process
Normal
Conversation
Thought
Process
Normal
Conversation
Thought
Process
200
200
200
100
100
100
50
50
200
50
200
25
200
114
111
110
108
105
104
102
99
99
99
96
96
95
6-31
-------
TABLE 6. 6 (CONTINUED)
LOW SPEED, HIGH ACCELERATION TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Apartment Interior
Frame House
Interior
Office Interior
Apartment Interior
Office Interior
Frame House
Interior
Apartment Interior
Frame House
Interior
Frame House
Interior
Apartment Interior
Office Interior
Apartment Interior
Frame House
Interior
Office Interior
Frame House
Interior
Human
Activity or
Condition
Asleep
Normal
Conversation
Normal
Conversation
Thought
Process
Thought
Process
Asleep
Normal
Conversation
Thought
Process
Normal
Conversation
Asleep
Normal
Conversation
Thought
Process
Asleep
Thought
Process
Thought
Process
Distance from
Road Centerline
(ft)
200
25
25
100
100
200
12.5
100
12.5
100
12.5
50
100
50
50
at 50 Feet
to Preclude
Annoyance
(dB(A))
94
93
93
93
90
90
90
89
88
88
87
87
84
84
84
6-32
-------
TABLES. 6 (CONTINUED)
LOW SPEED, HIGH ACCELERATION TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Urban Sidewalk
Outdoor
Residential
Apartment
Interior
Apartment Interior
Frame House
Interior
Frame House
Interior
Office Interior
Urban Sidewalk
Outdoor
Residential
Apartment
Interior
Apartment
Interior
Frame House
Interior
Outdoor
Residential
Frame House
Interior
Office Interior
Human Distance from
Activity or Road Centerline
Condition (ft)
Ambient Level
Normal
Conversation
Asleep
Thought
Process
Asleep
Thought
Process
Thought
Process
Ambient
Level
Normal
Conversation
Asleep
Thought
Process
Asleep
Thought
Process
Thought
Process
Thought
Process
50
200
50
25
50
25
25
25
100
25
12.5
25
200
12.5
12.5
at 50 Keel
to Preclude
Annoyance
(dB(A»
83
82
82
81
79
78
78
77
76
76
75
73
73
73
72
6-33
-------
TABLE 6-6 (CONTINUED)
LOW SPEED, HIGH ACCELERATION TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Urban Sidewalk
Outdoor
Residential
Apartment Interior
Frame House
Interior
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Human Distance from
Activity or Road Centerline
Condition (ft)
Ambient
Level
Normal
Conversation
Asleep
Asleep
Thought
Process
Asleep
Normal
Conversation
Thought
Process
Asleep
Normal
Conversation
Thought
Process
Asleep
Thought
Process
Asleep
Asleep
12.5
50
12.5
12.5
100
200
25
50
100
12.5
25
50
12.5
25
12. 5
at 50 Feet
to Preclude
Annoyance
(dB(A))
71
70
70
68
67
66
64
61
60
58
55
54
49
48
42
6-34
-------
TABLE 6. 7
CONSTANT HIGH-SPEED TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Apartment
Interior
Office
Interior
Frame House
Interior
Apartment
Interior
Office
Interior
Frame House
Interior
Apartment
Interior
Office Interior
Apartment
Interior
Frame House
Interior
Office Interior
Frame House
Interior
Apartment
Interior
Human Distance from
Activity or Road Centerline
Condition (ft)
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Normal
Conversation
Thought
Process
Normal
Conversation
Thought
Process
Thought
Process
Normal
Conversation
200
200
200
100
100
100
50
50
200
50
200
200
25
at 50 Feet
to Preclude
Annoyance
(dB(A))
117
115
114
111
109
108
105
103
102
102
100
99
99
6-35
-------
TABLE 6. 7 (CONTINUED)
CONSTANT HIGH-SPEED TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Apartment Interior
Office Interior
Frame House
Interior
Apartment Interior
Frame House
Interior
Office Interior
Apartment Interior
Frame House
Interior
Frame House
Interior
Apartment
Interior
Office Interior
Apartment
Interior
Office Interior
Frame House
Interior
Frame House
Interior
Human
Activity or
Condition
Asleep
Normal
Conversation
Normal
Conversation
Thought
Process
Asleep
Thought
Process
Normal
Conditions
Thought
Process
Normal
Conversation
Asleep
Normal
Conversation
Thought
Process
Thought
Process
Asleep
Thought
Process
6 36
Distance from
Road Centerline
(ft)
200
25
25
100
200
100
12.5
100
125
100
12.5
50
50
100
50
at 50 Feet
to Preclude
Annoyance
(dB(A))
97
97
97
96
94
94
93
93
92
91
91
90
88
88
87
-------
TABLE 6-7 (CONTINUED)
CONSTANT HIGH-SPEED TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Apartment
Interior
Apartment
Interior
Frame House
Interior
Outdoor
Residential
Office Interior
Frame House
Interior
Apartment
Interior
Apartment
Interior
Frame House
Interior
Frame House
Interior
Outdoor
Residential
Office
Interior
Apartment
Interior
Human
Activity or
Condition
Asleep
Thought
Process
Asleep
Normal
Conversation
Thought
Process
Thought
Process
Asleep
Thought
Process
Asleep
Thought
Process
Normal
Conversation
Thought
Process
Asleep
Distance from
Road Centerline
(ft)
50
25
50
200
25
25
25
12.5
25
12.5
100
12.5
12.5
at 50 Feet
to Preclude
Annoyance
(dB(A))
85
84
82
82
82
82
79
78
77
77
76
76
73
6-37
-------
TABLE 6-7 (CONTINUED)
CONSTANT HIGH-SPEED TRUCK OPERATION NOISE LEVELS
AT 50 FEET TO PRECLUDE ANNOYANCE IN VARIOUS
ENVIRONMENTAL SITUATIONS
Environmental Situation
Truck Noise
Activity Site
Outdoor
Residential
Frame House
Interior
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Outdoor
Residential
Human
Activity or
Condition
Thought
Process
Asleep
Normal
Conversation
Thought
Process
Asleep
Normal
Conversation
Thought
Process
Normal
Conversation
Thought
Process
Asleep
Thought
Process
Asleep
Asleep
Distance from
Road Centerline
(ft)
200
12.5
50
100
200
25
50
12.5
25
50
12.5
25
12.5
at 50 Feet
to Preclude
Annoyance
(dB(A))
73
72
70
67
66
64
61
58
55
54
49
48
42
6-38
-------
As constructed, Tables 6-6 and 6-7 provide values of "Truck Noise"
at 50 ['"Vet to Preclude Annoyance" for the various environmental
situations defined. The values of these noise level calculations were
based on the quantitative guidelines defined previously in this section
(and Appendix B). The guidelines defined include the acceptable ambient
noise levels for selected human activities at particular activity sites,
the architectural-acoustic descriptions of the activity sites, and the
ambient noise level increase criteria for substantial annoyance. Ad-
justment in any ot all of these quantitative guidelines for the analysis
procedure are easily made. The net adjustment is simply added alge-
braically to the values given in the column entitled "Truck Noise at
50 Feet to Preclude Annoyance. " For example, if it is desired to
replace the 10 dB(A) intrusion noise criterion with a 5 dB(A) criterion,
the change is -5 dB(A). If, in addition, it is felt that a selected am-
bient level for a particular environmental situation is too low and that
it ought to be increased by 7 dB(A), then the net adjustment is -5+7 or
+2 dB(A). Each entry in the above mentioned column is then decreased
by 2 dB(A) to accommodate this situation.
6-39
-------
REFERENCES FOR SECTION 6
1. "Information of Levels of Environmental Noise Requisite to Pro-
tect Publie Health and Welfare with an Adequate Mat-gin of
Safety." EPA Report 550/0-74-004. March 1074.
2. "Methods for Calculation of the Articulation Index," American
National Standard ANSI S3. 5-1969.
3. "House Noise-Reduction Measurements for Use in Studies of Air-
craft Flyover Noise, " Society of Automotive Engineers Report
AIR 1081, October 1971.
4. Knudson, V. O. and C. M. Harris, Acoustic Designing of Archi-
tecture, Wiley, 1950.
5. Beranek, L. L. (ed.), Noise and Vibration Control. McGraw-
Hill, 1971.
6. Lyons, R. H., Lectures in Transportation Noise, Grozier Pub-
lishing, 1973.
7. "Report to the President and Congress on Noise, " Grozier Pub-
lishing, 1973.
8. "Comprehensive Transportation Studies," Willard Smith and
Associates.
9. "Population Distribution of the United States as a Function of Out-
door Noise Level, " EPA Report.
10. Cook, R. K. and Peter Chrzanowski, "Transmission of Noise
through Walls and Floors, " in Handbook of Noise Control
McGraw-Hill, 1957. ~
6-40
-------
SECTION 7
ECONOMIC CONSEQIIKNCKS OK NOTSK CONTROL
tt'TROTHJCTlON
This section, using the three hypothetical models described
earlier in this document, evaluates the several standards and respec-
tive effective dates in terms of costs, and, to a limited degree
economic impact to determine the degree of disruption that, might
remit among truck manufacturers and associated industries. The
basis for the majority of data contained in this section is derived from
tvcstucT.es performed, under EPA sponsorship, for the purposes
of tMs ..tuiy (F.ef3r ernes I aad 2),
Ecotomlc impact is of particular importance in assessing pro-
ouction P;ad time, A more detailed discussion of typical truck
KianmactV'rur Tear times to implement design changes cf the type
envisioned to meet noise control requirements is given in
Appendix N,
Modei_J_ postulates a new diesel engine truck noise level of
8" dEx'A) off-active ia 1977, A two-year period to comply with this
level would be followed with a level of 80 dB(A) effective for 1981
modr;.f. year new trucks. A level of 75 dB(A) for 1983 model year
trucks is further evaluated in this model.
Mo4e£2_ is ihe same as model 1. However, it looks at the costs
associf* e-i with gaso.iine trucks. An 80 dB(A) level effective in 1978
and a 75 dB(A) level in 1931 were postulated.
7-1
-------
Model 3 models both gasoline and diesel engine trucks on the
time schedule proposed in model 2, but at the levels cited for diesol
trucks in model 1 and for gasoline trucks in model 2.
The cost data contained in this section are based to a substantial
degree on studies performed under EPA sponsorship (References 1
and 2). Cited costs were arrived at by independent noise control
engineers using known noise control techniques and hardware.
COST OF COMPLIANCE
Changes in Truck Manufacturing Costs
Table 7-1 gives to the new truck purchaser the anticipated retail
price increases that could result from incorporating noise abatement
measures which have been hypothesized as being potentially necessary
to meet three different trucknoise levels. * Possible price increases
are grouped by engine duty class, fuel type, and manufacturer.
Gasoline engines have, for purposes of cost analysis herein, been
considered as a single class.
*Cost increases are presented in terms of possible purchaser retail
price increases to protect proprietary confidential manufacturing
cost information.
7-2
-------
TABLE 7-1 ESTIMATED RETAIL-PRICE L INCREASES
-3
CO
Engine Family/
Engine Mamuacturer
Gasoline Engines
All Manufacturers
Medium-duty
Diesel Engines^
Manufacturer:
D
F
C-
Heavy-duty
Diesel Engines2
Manufacturer:^
A
A
B
B
C
C
F
F
Model 1 Model 2 Model 3 Estimated Market Share
83 dB(A) 80 dB(A) 75 dB(A)1 by Engine (percent)*
$ 0 $ 125 $ 300 65.00
$125
100
125
'$
210
300
275
$1, 250
1,250
1,250
2.2
0.77
0.17
$200
150
425
325
100
0
0
125
0
$ 400
350
1,000
800
400
125
150
325
125'
$1, 350
1,250
1,300
1,000
1,250
525
1,250
1,250
525
0.9
12.0
6.0
6.0
0.47
4.8
1.5
.23
.02
Notes: Cost is stated in terms of retail list price increases.
Refers to severity of service rather than Gross Vehicle Weight (GVW).
o
Multiple listings for individual manufacturers indicate major groupings of that maker's engirds.
4 '
Based on 1973 production.
-------
Substitution of a quieter engine for a noisy one is possible within
the medium duty and heavy duty classes (but not between classes).
Substitution of gasoline engines for medium duty diesel engines is
possible. Possible noise control measures and their individual
estimated contributions to overall retail price increases are given
in Appendix I, Tables 1-1 and 1-2. Additional insight into the
relative impact of various noise control measures is provided by
Table 7-1, which shows the relative market share (1973) of each
family of medium and heavy duty engines installed in new trucks.
The price estimates in Table 7-1 assume an orderly change in
manufacturing processes and adequate lead time. They do not
include considerations of factory testing, prototype certification, or
other compliance costs that may be imposed by regulatory actions;
these are dealt with in "Cost of Compliance Testing," page 7-10.
Figure 7-1 gives manufacturers' estimates of the increase in the
retail cost of trucks when quieted to various illustrative levels as
well as independent estimates from Table 7-1, which shows that:
1. Retail list price increases are generally lower for gasoline
engine powered trucks than for diesel engine powered trucks.
2. At each illustrative noise level, there is a wide range in cost
increases among diesel engine powered trucks.
3. Model 3 imposes a greater cost increment than either of the
first two models, with the exception of engine manufacturer
B.
7-4
-------
I
en
A Gasoline Engine, Manufacturers' Estimates
D Oiesei Engine, Manufacturers' Estimaies
O Oiesei Engine, independent Estimates
(Average of Figures in Table 7.1)
400
800 1200 1600 2000 2400
INCREASE IN RETAIL PURCHASE PRICE ($)
2800
3200
Figure 7.1. Increase 1n Retail Purchase Price for New Trucks for Various
Illustrative Noise Levels Measured According to the SAE J366b
Test Procedure.
-------
Gasoline engine powered trucks tend to cost less to quiet than
diesel engine trucks because they are generally quieter to begin
with. The main reason for the price difference among diesel engines
is that those produced by some manufacturers are inherently noisier
than others and, therefore, require different noise control methods,
as shown in Appendix I. The increase appearing in model 3 com-
pliance costs occurs because at these modeled levels most, if not
all, diesel trucks will require an engine enclosure. Based on current
practice, such an enclosure would probably be built as an integral
part of the truck cab structure. This enclosure will involve major-
retooling from current production machinery. The costs shown are
believed to be "worst case" costs that could be directly ascribed
to measures taken as a specific result of Federal noise standards.
In fact, such retooling may be required over time due to design,
performance or safety requirements.
In addition to the engine other noise sources that may well have
to change include the cooling and exhaust systems. Models 1 and
2 indicate that most manufacturers may have to make primary
changes in the cooling system. These changes may include, for
example, replacing current fans with larger, slower-turning fans
that have carefully designed shrouding and that use a thermostatically
controlled fan clutch phased with a shutter thermostat. A fan clutch
would eliminate the need for shutters on trucks operating in all but
the coldest environments, and would eliminate fan stall as a noise
source. Model 3 reveals the likelihood that a high-technology
7-6
-------
fan system could be required. The costs of implementing these
measures are detailed in Appendix f.
Model 1 shows that Tew dlcsol trucks will rrqnlrc oxhiniMl
system modifications. However, advanced exhaust systems, in-
cluding mufflers with outer wrapping and vibration-isolated clamps
for mounting the exhaust pipe to the engine, could be required to meet
the standards hypothesized in model 2. For model 3, exposed
exhaust pipes may require lagging (wrapping) to increase the trans-
missionloss and isolate shell vibration. The cost of these treatments
are listed in Appendix I.
Changes in Truck Operating Costs
Adding noise control devices to trucks has the effect of changing
various physical characteristics: primarily the gross vehicle weight
(GVW), the backpressure imposed on the engine by the muffling sys-
tem, and the power required to run accessories such as the fan.
Changes in these parameters will, in general, change the truck's
fuel consumption per mile and, hence, the annual fuel costs incurred.
This change in fuel costs and the incremental cost of maintaining the
truck designed to meet more stringent noise levels than at present
constitute the two elements of annual operating cost addressed here.
Other possible effects of equipment modifications to achieve noise
abatement are reduction of the truck's maximum speed, resulting
from decreased engine power available to drive the wheels, and
reduction of the truck's maximum payload, resulting from an increase
in tare (empty) weight. The second effect appears to be negligible
when averaged over the entire truck fleet (Reference 1) and so is
7-7
-------
not developed further. This leaves the problem of reduced
maximum speed, which may entail some cost to the operator since
the truck would, in principle, be able to travel fewer revenue-miles
per year. However, recently imposed reduced national speed limits
make this a major issue. Moreover, although trucks maybe designed
to operate at a speed higher than legally allowable, obviously it must
be presumed that they will remain within the legal limits; hence
design speed as a bench mark may be of questionable validity.
The approach to the problem of speed reduction taken here is
to assume that the purchaser of a new truck will specify an engine
large enough to run the truck at the same top speed of which the
unquieted version would be capable, i. e., present production. The
cost of this extra horsepower, then, is reflected in the purchase
price of the truck. The noise control treatments therefore induce
a worst case indirect change in the owner's capital cost, in addition
to the direct impact on capital cost referred to above.
The development of operating and indirect capital cost increases
is contained in Appendix J. The results of that development are sum-
marized here. Changes in operating expenses are shown in Table
7-2a.
Table 7-2a indicates that the horsepower savings associated with
quiet fans result in a net cost savings for most trucks at most levels.
Theoretically, such savings could be ascribed to the noise control
effort. However, (1) it is possible that truck operators will simply
use the fan power savings to increase speed; and (2) market forces
may eventually dictate such a beneficial design modification, even
7-8
-------
without considerations of noise reduction. Therefore, the operating
costs have been computed to exclude the fan horsepower savings to
again develop a worst case scenario. The results are shown in Table
7-2b.
TABLE 7-2a
CHANGES IN ANNUAL COST (FUEL PLUS MAINTENANCE
EXPENSES) CAUSED BY NOISE CONTROL TREATMENTS
(INCLUDES FAN SAVINGS)
Annual Cost Change
Model
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Note: Parentheses denote net savings.
TABLE 7-2b.
CHANGES IN ANNUAL COST (FUEL PLUS MAINTENANCE
EXPENSES) CAUSED BY NOISE CONTROL TREATMENTS
(WITHOUT FAN SAVINGS)
Annual Cost Increase
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Model 1
($ 53)
($120)
($ 63)
($224)
Model 2
($ 96)
($238)
($ 63)
($ 66)
Model 3
($ 84)
($210)
$ 51
$116
Model 1
0
0
$ 9
$19
Model 2
$ 9
$ 19
$ 9
$176
Model 3
$ 21
$ 44
$123
$359
7-9
-------
The cost of extra horsepower needed to maintain the original
level of service is shown in Table 7-3a. The fan savings result
in a smaller required total engine output and, hence, a reduction In
initial price. For the reasons listed in the preceding paragraph,
however, these savings may not be realized. The indirect capital
cost increase is therefore shown in Table 7-3b with fan savings ex-
cluded. The apparent cost of extra horsepower required by noise
control treatments is small.
Cost of Compliance Testing
Another noise control cost will be the cost of testing production
trucks to ensure end-product compliance. The cost thus incurred by
the manufacturers will depend on various factors, such as the ease
with which the necessary or required tests can be performed. The
enforcement procedure described in Section 10 appears to involve
only a nominal cost and no detailed cost analysis is therefore pre-
sented. Should an enforcement procedure significantly differ from
that described in Section 10 further cost impact analysis will be
necessary.
TABLE 7-3a
CHANGES IN CAPITAL COST INDIRECTLY CAUSED
BY NOISE CONTROL TREATMENTS
(INCLUDES FAN SAVINGS)
Capital Cost Change
( ) Denotes Net Savings
Model 1 Model 1 Model 3
Gasoline - medium ($ 30) ($ 60) ($ 58)
Gasoline - heavy ($ 98) ($210) ($204)
Diesel - medium ($ 96) ($ 96) ($ 85)
Diesel - heavy ($360) ($336) ($326)
7-10
-------
TABLE 7-3b.
CHANGES IN CAPITAL COST INDIRECTLY CAUSED
BY NOISE CONTROL TREATMENTS
(WITHOUT KAN SAVINGS)
Capital Cost Increase
Model 1
Gasoline - medium 0
Gasoline - heavy
Diesel - medium
Diesel - heavy
COST IMPACTS'
Impact on Truck
0
0
0
Manufacturers
Model 2 Model 3
0 $ 2
0 $ 6
0 $11
$12 $35
Market research among truck manufacturers indicates that cost
increases on the order of those resulting from noise control retro-
fits (see Table 7-1) would likely be completely passed on to the
consumer as equivalent price increases* with attendant normal
markup added on. Future sales may potentially be affected by any
future price increases or increases in truck operating costs. To
account for both of these possible effects, a worst case equivalent
price increase has been computed which consists of the actual price
increase plus the net present value of the operating cost increase
over the future life of the truck. * Table 7-4 gives the average equiv-
alent price increases for each type of truck, both including and ex-
cluding fan savings (s^e "Changes in Truck Operating Costs, " page
* The net present value was computed assuming a depreciation time
of 10 years and an interest rate of 10%.
7-11
-------
7-7). The figures in Table 7-4 wore derived by computing the
equivalent price increases explicitly for each major truck group and
then taking an average, weighted according to each group's market
share. The details of this computation are given in Appendix K.
Where savings from reduced fan power outweigh other cost increases,
the net gain in income could be assumed to be lost to the operator
under worst case computations, competitive pressures forced a low-
ering of freight rates. A worst case "zero" is consequently entered
for such cases.
Representative Prices
Gasoline Diesel
Medium $ 5, 746 $ 7, 246
Heavy 11,434 25.213
The midpoint estimate of elasticity (y) of -0. 7 is used.
dq/q = (-0.7) . p
where q is volume, dp is the change in equivalent price (Table 7-4),
and p is the price shown above.
7-12
-------
TABLE 7. 4
EQUIVALENT PRICE INCREASES FOR QUIETED TRUCKS
Model 1
Gasoline - medium 0
Gasoline - heavy 0
Diesel - medium 0
Diesel - heavy 0
Gasoline - medium 0
Gasoline - heavy 0
Diesel - medium $160
Diesel - heavy $311
Source; Appendix K.
Model 2
Model 3
With Fan Savings
0 0
0 0
0 $1357
0 $1506
Without Fan Savings
$ 180 $ 431
$ 242 $ 576
$ 319 $1,986
$1,581 $3,360
To estimate the impact of the equivalent price increases in
Table 7-4 on possible future sales, an estimate of the price elasticity
of demand for trucks was made. Rigorous estimates of this quantity
are not currently available, but market research indicates a probable
range of -0.5 to -0.9. The midpoint of this range, -0.7, was
assumed as a working value. The percentage reduction in sales for
a given price increase was then obtained by multiplying the percentage
price increase by the elasticity. The percentage sales decreases
corresponding to the price changes as shown in Table 7-4 are given
in Table 7-5.
7-13
-------
The differences among the three noise models used relates to
the times at which the various noise levels in the models become
effective. The three models are shown in Table 7-6.
TABLE 7-5
ESTIMATED PERCENTAGE REDUCTION IN ANNUAL VOLUME
Model 1 Model 2 Model 3
With Fan Savings
Gasoline - medium 0 0 0
Gasoline - heavy 0 0 o
Diesel - medium 0 0 13.11%
Diesel -heavy 0 0 4.18%
Without Fan Savings
Gasoline - medium 0 2.20% 5.25%
Gasoline - heavy 0 1.48% 2.53%
Diesel - medium 1.54% 3.09% 18.31%
Diesel -heavy 0.86% 4.39% 9.33%
Based on "average" or "representative" truck prices (see A. T%
Kearney, 1974).
TABLE 7-6
ALTERNATIVE NOISE REDUCTION SCHEDULES
Model 1 Model 2 Model 3
Level 1-83 dB(A)
Level 2-80 dB(A)
Level 3-75 dB(A)
All Trucks
1977
1981
1983
All Trucks
1977
1978
1981
7-14
Gasoline
1977
1978
1981
Diesel
1977
1981
1983
-------
The absolute reduction in future sales ia obtained by multiplying
the percentages in Table 7-5 by the baseline volume forecast; i.e.,
projected future sales of unquieted trucks. The baseline projection
is given in Table 7-7. Complete tables of future volumes for eaeh
of the three quieting options, with and without fan savings, are given
in Appendix L.
So far, no judgment has been made as to whether fan savings
should or should not be included in the sales forecasts. At this
point, a hypothesis is made concerning the inclusion of fan savings
in the impact analysis. Any design change which produces net cost
savings in and of itself will ultimately be introduced as a result of
market pressure. This applies to improved fans. The probable effect
of new truck noise control regulations, however, may be to cause
adoption of such design improvements earlier than would otherwise
be the case. The noise control program can, therefore, claim
credit for fan savings during the period prior to the time when market
forces would otherwise result in introduction of the quiet fan. This
period is assumed to be three years. The composite volume reduction
forecasts are therefore constructed from the tables in Appendix L by
including fan savings for the first three years under model 1 conditions
(1977-1979 inclusive) and, excluding fan savings thereafter (1980-2000).
The composite volume forecasts are shown in Figures 7. 2 through
7. 5 for each truck category. In each figure, the baseline forecast and
the revised forecasts are laid out for each of the three models. The
7-15
-------
figures show that from the models used the maximum differential
impact occurs between 1980 and 1982, depending on the truck
category. In general, model 1 shows more units being sold during
this period than does Model 3; Model 2 is intermediate. In the case
of heavy gasoline trucks, for example, 793 more units are sold in
1980 in model 1 than in models 2 and 3. For heavy diesels, models
1 and 2 result in 11,125 more units being sold than would be in model
3 in 1982.
To estimate the relative impact on truck manufacturers, the
cumulative impact on dollar sales is computed for each model over
the period 1977-1985, the period within which the models differ. The
percent reduction in total dollar sales of all types of trucks over
the period 1977-1983 is shown in Table 7.8. Model 3 produces the
greatest impact while model 1 gives the least impact. The effect
of quieting gasoline engines on a shorter-term schedule than diesel
engines (model 3) shows a slightly greater adverse impact than if
all trucks were quieted on a longer-term schedule.
7-16
-------
TABLE 7-7
CASELEsE FORECAST OF DOMESTIC TRUCK SALES BY ENGINE TYPE1
(THOUSANDS OF TRUCKS)
Medium-Duty Trucks
1976
1977
1978
1979
1080
1381
1982
196'.?
19S4
1985
7* 19S6
t^ 1957
19S8
1989 •
1990
1991
1992
1993
109-1
19£5
1996
lf'97
isra
1999
2000
Gasoline
203.9
206.8
209.8
212.8
ras. 7
JJ1S. 7
221.6
.'124. 6
1^28.5
231.5
234. 4
237.4
241.3
244.3
248.2
251.2
255. 1
258. 1
262.0
;:C5. 9
2G9.9
.".73. 8
.176.8
280.7
284.7
Diesel
3.1-
3.2
3.2
3.2
3.3
3.3
3.4
3.4
3.5
3.5
3.6
3.6
3.7
3.7
3.8
3.8
3.9
3.9
4.0
4.1
4.1
4.2
4.2
4.3
4.3
Total
207
210
213
216
219
222
225
228
232
235
238
241
215
248
252
255
259
2G2
266
270
270
278
281
285
289
Heavy-Duty Truck
Gasoline
40.4
39.4
38.1
38.4
3S.6
38.7
38.8
38. S
38.7
35.6
3S.4
3S.1
37.7
37.2
36.6
35. 9
3o. 0
33.9
32.8
31.3
32.3
34. 2
35. 7
37.2
33. S
uicsei
164.G
173. G
184.9
194. G
204.4
214.3
225.2
230. 2
248.3
260.4
273. G
287.9
302.3
316.8
333.4
350.1
367.0
385.1
404. 2
424.5
443.2
461.8
481.3
501.8
523.2
s
Total
205
213
223
233
243
253
264
275
287
299
312
326
340
354
370
386
402
419
437
456
476
496
517
539
562
Total
(All Trucks)
412
423
436
449
462
475
489
503
519
534
550
567
•535
602
622
G41
601
681
703
72(3
730
774
79S
824
851
!„
Source; A. T. Kearney, 1974. Forecasts tor years 1S7G-1978 based on market research.
for years 1979-2000 based on following annual growth rates:
Gasoline - medium : 1.4
Giisoline - hcnvy : -0.3
DJGocl - r»ioc:ii:r/. : 1.5
D;oso] - iu-c.vv : 5.0
-------
300
O
«D
N
H
z
=> 260
U.
O
in
o
z
<
§ 240
O
X
h-
O
CM
CM
200
1976
BASELINE:
MODEL 1
MODELS 2, 3
1980
1985
1990
1995
2000
Figure 7-2 Volume Forecasts - Baseline and Quieted Gasoline-Medium .
7-18
-------
42.5
BASELINE
MODEL 1
MODELS 2.3
30.0
1976
1980
1985
1990
1995
2000
Figure
7-3
Volume Forecasts - Baseline and Quieted Gasoline-Heavy,
7-19
-------
5,0
4.5
to
h-
2 4.0
:D
u.
O
(O
O
2
<
to
g 3-5
3.0
2.5
1976
BASELINE
MODRLS 1,2
MODEL 3
1980
1985
1990
1995
2000
Figure 7-4
Volume Forecasts - Baseline and Quieted Diesel-Medium.
7r20
-------
600
500
400
U.
o
-------
TABLE 7-8
CUMULATIVE COST IMPACT OF ALTERNATIVE
QUIETING SCHEDULES
Cumulative
Reduction In
Cumulative Sales due to Percent
Baseline Sales* Quieting Options Reduction
1977-1983 1977-1983 in Cumulative
($ millions) ($ millions) Sales, 1977-1983
Model 1
Model 2
Model 3
Source:
48,
48,
48,
Figures 7-2
080
080
080
through 7-4.
1,
1,
1,
430
560
120
3.
3.
4.
0
2
4
* Assumes the following average prices (A. T. Kearney 1974):
Gasoline - medium $ 5, 746
Gasoline - heavy $ 11,434
Diesel - medium $ 7, 246
Diesel - heavy $ 25, 213
In addition to possible sales volume changes, other impacts on
truck manufacturers could be a standardization of the product offering
and changes in production operations, a reduction in the number of
components and options offered by exhaust muffler systems, and
cooling systems. Because these components currently have wide
variations in noise levels, an anticipated effect of noise standards
could be to eliminate many of them as variations in a given model
family.
In models 1 and 2, the addition of acoustic treatments such as
side panels, sheet metal supports, and fan modifications may re-
quire some modifications in fabrication and assembly operations.
7-22
-------
Model 3 indicates that changes in production operation may occur
because virtually all trucks would appear to require at least partial
engine enclosures. Such enclosures could entail redesign of some
cabs. The costs of these design and retooling actions may or may
not be attributable wholly or in part to noise abatement standards,
dependant on style or design changes that may be effected whether or
not Federal noise standards are established. Estimates of increased
engineering, design, and test costs for the total medium and heavy
duty truck industry were, however, considered and are shown in
Table 7-9. These expenditures could be expected to potentially
result in employment increases of several hundred personnel.
TABLE 7-9
ESTIMATED TOTAL ENGINEERING, DESIGN, AND TEST INVEST-
MENT COSTS TO TRUCK MANUFACTURERS FOR NOISE CONTROL
IN THE MEDIUM AND HEAVY DUTY TRUCK INDUSTRY
Total Cost
(Millions of Dollars)
Model 1 20
Model 2 40
Model 3 120
Source; Discussions with truck manufacturers.
Several of the larger manufacturer representatives expressed
concern over what they consider to be potentially large development
costs for noise levels such as those used in model 3. They state that
if such development costs appear too high in relation to volume, the
manufacturers could be expected to withdraw from the low-volume
segments of the market and possibly eliminate those vehicle models
which have low potential volume and require high development costs.
7-23
-------
The overall impact from these moves on manufacturers' shares of
the market would, however, on the whole, appear to be minor.
Because of the basically strong position of the truck manufactur-
ing industry in the economy at this time, the potential volume changes
that could occur as the result of Federal noise control regulations
would in general appear to have little overall impact on most firms.
The truck manufacturing industry has been growing at a rate of 7
to 8% per year (in current dollars) from 1966-1972. The value of
shipments was estimated at $7.5 billion in 1972 and value added is
estimated at $2. 0 billion. These figures include light, medium, and
heavy duty trucks. Imports were about 10-11% of 1973 domestic
shipments and exports about 6-7%.
In 1973, truck manufacturing accounted for about 120, 000 jobs
in the U. S. Again, this represents employment in the production of
all classes of trucks.
As a generalization, the major manufacturers are better able
than small ones to adapt to the significant equipment changes that may
be required as a result of certain noise standards. This ability
reflects superior financial resources and a larger scale of operation
which supports specialized personnel resources and organized re-
search and development efforts that can be brought to bear on the
adjustments required.
Table 7-10 indicates the market share of each manufacturer in
the medium and heavy duty market.
Most truck manufacturers seem to anticipate few significant
equipment modifications in truck manufacturing assembly operations
7-24
-------
if partial engine enclosures are not required to meet noli e standards
which may be imposed. Cost increases resulting from noise abate-
ment hardware are expected to be passed on to customers. In
addition, no change in pricing practices or dealer policy is antici-
pated; thus it could be anticipated that the customary markup will be
added to such manufacturers' costs, resulting in the price increases
postulated elsewhere in this study.
TABLE 7. 10
MARKET SHARE OF MEDIUM AND HEAVY DUTY TRUCKS
BY MANUFACTURER
Truck Manufacturer %
Chevrolet 14.2
General Motors 11.7
Diamond Reo 1. l
Dodge 12. 1
Ford 23.7
Duplex . l
FWD .2
International Harvester 20. 2
Mack 6.3
White 5.9
Other 4.5
Impacts on Truck Users
Firms engaged in truck haulage will be affected by new truck noise
control measures through changes in their capital costs and cost of
operation. Using the estimated increases in purchase price and
operating cost developed in the models used in Section 7, the effects
7-25
-------
TABLE 7-11
I
to
MODELS OF POSSIBLE INCREASED CAPITAL COST (BASED
ON YEAR IN WHICH VARIOUS STANDARDS COULD TAKE EFFECT)1
($ THOUSANDS)
Model 1 - 1977
Model 2 - 1978
*>del 3 - 1981
Gasoline •
medium
Gasoline •
heavy
Diesel -
medium
Diesel -
heavy
Total
Excludes
2
Source:
o
Per Truck2
$ o
0
104
195
indirect capital cost
Figures from Table 7
Total3
$ 0
0
328
33,560
$33,888
savings due
~1 averaged
Per Truck2
$125
125
264
487
to fan treatments
within each truck
Total3 Per Truck2
$ 25,650 $ 300
4,693 300
818 1,129
86,092 1,119
$117,253
(see Section 7-2).
category.
Total3
$ 62,160
11, 199
3,048
217,422
$293,329
Numbers of trucks sold by category for each year obtained from Tables D-1 - D-4.
-------
on the trucking industry have been projected in several ways. These
include increases in annual capital outlays, annual costs of operation
during the first year that various noise levels become effective, and
annual costs of operation at such Lime as the entire fleet consists
of quieted trucks.
Table 7.11 portrays the increased capital outlay (excluding the
effects of fan savings) which the trucking industry could potentially
be impacted by in the first full year in which various noise levels
would hypothetic ally become effective.* This represents the change
in purchase price for each truck category times that year's sales
for that category. The largest effect is observed in model 3, for
which $294 million extra could possibly be paid at retail for that
year's trucks. Taking the 10H1 projected unit sales from Tables
D-l through D-4 and the average unit prices from Table 7-8, the
increase represents about 4. 5% of the total new vehicle capital outlay
for that year.
Table 7.12a and 7. 12b show computations for the without- and
with- fan savings cases, respectively, of the additional annual cost
(including depreciation, interest, operating, and maintenance
expenses) for the first full year during which various noise levels
could become effective. The basis for these tables is presented in
Appendix E. The models in Table 7.12a show that possible extra
* In Tables 7-12, 7-13a, and 7-13b, only one initial year per noise
level is considered; optional implementation schedules are not
shown. The costs which would be shown if different schedules were
used, however, are not substantially different from those given
here.
7-27
-------
annual costs associated with operating quiet trucks during the first
year of each of the three models used itu-reuses from $11 million Tor
model 1 to $168 million for model 2. Tnble 7. iL'b, on Ihe oilier
hand, shows that these costs are more than offset if one considers
the savings due to the use of lower-powered fans.
The maximum annual cost resulting from noise abatement is
reached when the truck population is 100% quieted. Cost estimates
were made for both 1990 and 2000. Making these estimates required
projection of truck population and average annual cost per unit by
type (e. g., medium diesels, etc.) and noise level to the year 2000.
The average annual cost was calculated in a manner similar to first-
year costs as described in the previous paragraph, but with operating
costs scaled to the trucks' annual average mileage rather than to
first-year mileage. Population forecasts were obtained by using the
model described in Section 8 and the volume forecasts presented in
Appendix L.
Those volume estimates for the period 1976 to 1978 were based
on extrapolations from sales forecasts provided by truck manufac-
turers. Heavy trucks are predicted to grow at an annual rate of
4. 3% and medium trucks at 1.4%. These form the baseline estimates
that were adjusted downward to reflect the quantity adjustment re-
sulting from increased purchase and operating costs (which are the
result ofnoise abatement). Since these estimates are simple extrap-
olations, change in technology, demand for transportation services,
and other factors could result in the actual population in future years
being larger or smaller than the predicted population.
7-28
-------
TABLE 7-12a
to
VD
MODELS OF POSSIBLE INCREASED ANNUAL COST
(EXCLUDES FAITSAVINGS) ($ MILLIONS)
(BASED ON YEAR IN WHICH VARIOUS STANDARDS COULD TAKE EFFECT)
Modell - 1977
Model 2 - 1978
Model 3 - 1981
Gasoline
medium
Gasoline
heavy
Diesel -
medium
Diesel -
heavy
Total
Source:
Per Truck1
$ 0.
0.
33.84
64.92
Appendix M.
Total2
$ 0.
0.
0.11
11.17
$11..28
Per Truck1 Total2
$ 46.00 $ 9.44
60.00 2.25
65. 00 . 20
335.52 59.31
$71. 20
Per Truck1 Total2
$108.40 $ 22.46
142. 20 5. 31
404.02 1.09
715.86 139.10
$167.96
n
Truck volume for each year by truck category obtained from Appendix L, Tables D-l through D-4.
-------
TABLE 7-12b
MODELS OF POSSIBLE INCREASED ANNUAL COST (INCLUDES
FAN SAVINGS) ($ MILLIONS) (BASED ON YEAR IN HHICH
VARIOUS STANDARDS COULD TAKE EFFECT)
Model 1 - 1977
Model. 2 - 1978
Model 3 - 1981
. Per Truck2
i
u>
o
Gasoline -
medium
Gasoline -
heavy
Diesel -
medium
Diesel -
heavy
Total
($107.
( 219.
( 85.
( 321.
00)
60)
12)
70)
Total3
($22.
( 8.
( .
( 55.
($86.
13)
65)
27)
85)
90)
Per Truck2
($208,
( 453.
( 56.
( 58.
00)
36)
36)
68)
Total3
($43.
( 16.
, .
( 10.
($71.
64)
59)
18)
85)
26)
Per Truck2 Total3
($144. 60) ($31. 62)
( 365.00) ( 14.16)
135.82 .39
1.66 .34
($45.05)
Parentheses denote net savings.
"Source: Appendix M.
Truck volume for-^asoline trucks in each of the models is the same as baseline volume (Table 7~7)
Truck volume for diesel trucks obtained from Appendix D, Tables D-5 and D-€.
-------
The two tables Lvlo\v gi\v the possible annual total cost of quieting by
type of truck as well as totals for all types for l»»*>0 A tut 2000.
TABLE 7-13a
INCREASED TOTAL ANNUAL COSTS YEAR 1990
($ thousands)
Type
Gasoline - medium
Diesel - medium
Gasoline - heavy
Diesel - heavy
Total for all types
Model 1
115,286
6,895
26,374
1.034.875
Model 2
114,598
5,866
26,194
914,968
Model 3
100,007
5,806
22,408
911.366
1,183,430 1,061,626 1,039,647
TABLE 13b
INCREASED TOTAL ANNUAL COST YEAR 2000
($ thousands)
Type
Gasoline - medium
Diesel - medium
Gasoline - heavy
Diesel - heavy
Total for all types
Model 1
147,482
8,637
28,633
1,900,886
Model 2
147,431
8,523
28,633
1,878,459
Model 3
145,970
8,523
28,080
1,877,717
2,085,638 2,063,046 2,060,290
7-31
-------
These cost estimates do not include any fuel savings which may
be brought about by the use of fan clutches. The costs increase from
1990 to 2000, because the total population increaHew and the
percent of quieted trucks increases. In 1990, for example, with
the three models used, there are 699, 000 unquieted trucks (all over
10 years old) and in 2000 there are 24,000 unquieted trucks (all
over 10 years old).
These cost increases are large in the absolute, but are not
necessarily a large percentage of the cost of operating a truck nor
of the annual revenue earned by a truck. For example, a for-hire
heavy diesel truck averaging 50, 000 miles a year with an average
payload of 10 tons at a freight rate of $0.17 per ton-mile will earn
$85, 000 per year. The $532 annual cost per truck of operating as
shown in model 3 is thus about 0.6% of total revenues. In the case
of private carriers, in which the trucks are owned by a firm whose
chief income is from a source other than trucking, the cost in-
crease can be spread over an even larger income base.
Changes in truck retail prices and operating costs could con-
ceivably affect freight rates and the quantity of trucking services*
supplied by the trucking industry. The elasticity of the quantity of
trucking services with respect to the price of trucks is estimated
to be between -. 31 and -. 18. Thus, if noise abatement increases
truck retail prices by $1,000 (about a 4% increase), this could result
* "Trucking services" is here defined as the number of trucks times
the average lifetime mileage per truck.
7-32
-------
in a reduction in trucking "services" of 0.76 to 1. 24%. This does
not represent the decrease in trucking activity in terms of annual
ton-miles of freight or annual revenue; rather, it is the reduction
in the stocks of trucks and the increase in the lifetime miles a truck
ia driven.
A 4% increase for new trucks could theoretically result in a reduc-
tion in the stock of trucks of from 0. 8% to 2. 84%. In addition, the
lifetime mileage per truck will increase by from 0.16% to 1. 56%.
The reduction in the annual volume of freight carried by a truck
will depend upon the percentage change in freight rates and the elas-
ticity of demand for freight service. The elasticity of demand for
freight service is assumed to be between -0. 5 and -0.3. Depending
upon the degree of competition within the trucking industry, the extent
of competition from other modes, and the regulatory policy of the
ICC, some part of any possible increased cost of trucking services
will be passed on to shippers. This, of course, applies only to
common carriers. For contract haulers, the ICC does not regulate
rates but competition will likely still determine the amount of the
cost passed on. In addition, private truck fleets operated by firms
producing products other than transportation services may easily
pass cost increases through in the form of higher prices for their
products. The ability of a firm to recover increased trucking costs
depends upon the elasticity of demand for the product and the
ratios of trucking costs to total costs. All other things being equal, the
larger the proportion of trucking cost to total cost, the more likely
it is that the firm will absorb part of the increased trucking costs.
7-33
-------
Clearly, these impacts may be different for different geographical
regions, since the same products produced in different regions have
different magnitudes of transportation inputs.
The impact of noise standards and the resultant equipment
modifications that may be necessary upon all classes of truck users
(i.e., line haul, contract, and private) would appear likely to be very
small from the information resulting from the three models used,
since the cost of noise abatement represents an increase of less than
1% in the annual cost of owning and operating a large diesel truck.
The impact may be somewhat greater for smaller trucks; however,
smaller trucks are found primarily in private fleets, which is the
user class that should experience smallest impact.
The relatively small size of the cost increases can lead to the
conclusion that the impact on the trucking industry and on freight
rates will be negligible. This conclusion is further reinforced when
it is considered that, in the case of model 3, costs have been depicted
as an upper bound, or worst case scenario. The one segment of the
industry that may be altered is the owner-operator (contract) group.
Owner-operators tend to be credit-limited (i. e., have poorer credit
ratings), have less sophisticated accounting contracts, pay higher
prices for fuel and parts, and have poorer maintenance programs
than fleet operators. Given these disadvantages, an increase in
the price of trucking services (i.e., higher prices for new trucks
and/or increased fuel and maintenance costs) may impact directly
and severely on marginal producers. Trucking industry marketing
specialists estimate, however, that the majority of owner-operators
7-34
-------
will not be adversely affected by the worst case shown m model 3.
Impacts on Industries Associated with Truck Manufacturers
Changes in the design of trucks and in the number of trucks sold
will affect industries that supply goods and services to truck manu-
facturers.
Engine Manufacturers. The major diesel-engine manufacturers
are large, financially sound companies with strong technical capabil-
ities. They will likely find it advantagous and/or necessary to invest
resources in development programs aimed at reducing engine noise.
The specific product changes that each engine manufacturer could
need to make for each of the noise level models used in this study
are shown in Table A-2.
Because sales volume changes due to the noise emission standards
hypothesized in the three models are relatively small, no substantial
change in employment, number of operative plants, market shares,
and profitability would be expected. Noisier vehicle engines will
tend to be eliminated in time, but the associated production facilities
and equipment are transferable to other vehicle models having
quieter engines.
One large manufacturer of diesel engines estimates that three
years could be required to modify the engine for compliance with the
standards used in this study's model 2. The manufacturer could be
at a competitive disadvantage in the truck diesel engine market for
several years should standards such as those described for model 2
be Federally adopted. One possible result of this disadvantage could
be a shift in sales emphasis on the part of the manufacturer toward
7-35
-------
noil-truck markrts, with a consequent increase in the compet.il ion's
share of the truck market. This situation is discussed in detail
in Appendix !«'.
Muffler Manufacturers. A change in the product, mix of mul'l'lcr
sales will likely occur, if the noise standards require more techni-
cally sophisticated and higher-priced designs.
It is unlikely that the changes in truck volume forecasted would
have a significant impact on muffler manufacturers, assuming ade-
quate lead time for production realignments. No changes in market
shares would be expected, since no muffler manufacturer is consid-
ered to be in any better competitive position than any other in relation
to the noise standards that were modeled. The major muffler
manufacturers have apparently included in their forward planning
the possible impact of the Federal noise emission standards on their
business; raw material shortages and capacity constraints do not
appear likely to result from the noise standards modeled. No disrup-
tive effects on the industry are anticipated, because sales volume
reductions would probably be small.
Fan Clutch Manufacturers. Fan clutches are an integral part of
the various noise control equipment options and strategies outlined
in this analysis. Not only can fan clutches reduce noise but also
result in significant fuel savings. A review of the past market
acceptance of fan clutches puts the potential benefits of fan clutches
in perspective.
7-36
-------
Historically, most truck owners have not installed Can clutches
or have not been able to take advantage of the fuel savings if they
were installed. Fan clutches have had several technical and relia-
bility problems that hampered their use; these problems arc now
considered to be solved. Truck owners who have installed fan clutches
have preferred to increase speed and payload rather than save fuel
due to the lowered power requirements.
Currently, approximately 5% of heavy duty trucks are fitted with
fan clutches. It could be expected that most, and possibly all, medium
and heavy duty trucks would include fan clutches under models 2
or 3. As a rough approximation, employment in the fan clutch
industry could increase by 1, 500 to 2, 000 if this implication were
realized.
In short, significant growth in the fan clutch market would appear
likely, provided that historic resistance to fan clutches is overcome.
Federal noise emission standards could very well provide the impetus
to accelerate widespread fan clutch acceptance.
Truck Distributors. Channels of distribution and truck distribution
operations would not be expected to change materially as a result of
the noi«e emission standards modeled because sales volume changes
would be relatively small. Some accelerated buying immediately
before and after noise regulations become effective may occur as
customers try to avoid potential price increases. However, this
effect is expected to be minimal since the price increases apparent
from the hypothetical standards modeled would be small in compar-
ison to total truck retail price. Lowered distributor sales volume
7-37
-------
would be offset by higher dollar sales volume for quieted trucks and
a potentially slight increase in truck rental and leasing. However,
rental and leasing costs for quieted trucks could be expected to rise
based on costs associated with quieting.
Truck retail price increases, under model 3 conditions, appear
to be less than 5% of current prices. Generally, the requirement
to finance this increased cost could be met by end users. At the
same time, marginal credit operators will be somewhat more mar-
ginal. However, this level of price change, particularly with lead
times of several years to allow for appropriate planning, would seem
to be within the range which could be accommodated in the normal
course of business, and hence result in no disruptive effects in the
economy in general or related industries in particular.
IMPACTS ON THE NATIONAL ECONOMY
Transportation and Trucking in the U. S. Economy.
The total transportation sector within the U. S. economy has
doubled since World War II, while truck transport has increased
about sixfold. During this period, truck transport has grown from
82 billion ton-miles to 470 billion ton-miles. Truck transport
accounted for 18.7% of the total ton-miles in 1970 and 81.3% of the
total revenue. These figures indicate that trucks haul those products
for which relatively high rates per ton-mile are charged.
Trucks are gene rally faster and more flexible than other modes of
transport. The line haul speeds for trucks range from 40 to 55 mph,
7-38
-------
which is faster than any other mode except air freight. In addition,
trucks provide door-to-door service.
The greater speed of truck transport, together with smaller
volume for truckload shipments than for carload shipments by rail
gives the trucking industry a strong competitive position. Speed
reduces inventory costs by allowing firms tohold smaller inventories.
This applies more to products having high value per unit weight than
to bulky low-valued products.
In addition to the advantages trucks have as a primary means
of transport, they are also complementary to other modes. For exam-
ple, rail or water shipments arc often brought to and from terminal
facilities by trucks.
Impacts on Exports.
As models one and two illustrate, the extent of product modifi-
cations, will probably consist basically of specifying quieted com-
ponents from vendors. Domestic truck producers would be able to
export both quieted and unquieted products to foreign countries,
depending on local foreign noise regulations. U. S. manufacturers
will be in an improved competitive position in foreign markets that
require quiet trucks since they will have experience in the appli-
cation cf noise technology to their products.
A different situation exists under model 3 conditions,
however, because redesign of some truck models may be necessary.
In the case of redesigned models, domestic producers may have to
ship trucks incorporating at least some noise control measures and
associated costs, even though the foreign market competition and
7-39
-------
regulations may not require quieted trueks. On the other hand,
foreign markets that require trueks to meet, say, the standards
used in model 3 probably would not provide enough volume them-
selves to economically cause truck manufacturers to quiet their
vehicles to that level without the impetus of U.S. regulaton. In such
circumrtancee Federal noise regulation will make American com-
panies competitive where they would otherwise not have been.
Study of information from truck manufacturers indicates that they
expect no changes in export patterns due to Federal noise regulations.
Impacts on Imports.
Imports are not a large factor in the U. S. market for medium
and hea y duty trucks. The general reputation of medium and heavy
duty trx cks of foreign manufacture isthat they do not have the quality
to stand up to the tough line-haul conditions prevalent in the U. S.
It seem ; unlikely that Federal noise regulations will alter the po-
sition o imports within the U. S. market.
How ?ver, the United States has the largest motor vehicle market
in the w orld, which has attracted intense import competition. The
heavy d ity truck market appears to have good growth potential and
may we Ll attract import competition regardless of the noise stan-
ards.
It if, of course, possible that a foreign manufacturer may
develop technology that could result in significant noise reduction
from medium and heavy trucks. In such a case that technology could
establish a new "available technology achievable at reasonable cost"
base from which Federal regulations could be derived. This would
7-40
-------
potentially offer a unique and highly competitive advantage to foreign
manufacturers and a new door to American markets unless such tech-
nology was competitively adopted by U.S. firms.
Impacts on Balance of Trade. Based on the foreign trade factors
above, models 1, 2 and 3 indicate that no probable material impact
on the balance of trade would be anticipated.
Summary
This economic study, based on the three hypothical models cited,
indicates that the anticipated overall economic impact of the various
modeled noise regulatory levels on the truck manufacturing indus-
try, and industries dependent on trucks, would be expected to be low.
The following summarizes the impacts postulated from each of the
three models employed. Generally, the amount of cost increases
and levels of change in the industry volume are estimated as low.
As a result, disruptive impacts are not anticipated in most cases.
1. Model 1 - 1977. Cost changes and volume changes from
baseline conditions are minor. Industry would be expected
to continue its present growth pattern. No unemployment is
anticipated, nor are any disruptive impacts.
2. Model 2 - 1981. No disruptive impacts are indicated if a six-
year lead time is provided. The time is adequate to quiet
"noisy" engines by using immediately available technology.
Additionally the development of lower-cost techniques would
be possible and the economics of doing so might even indicate
that such development would be likely. Volume changes and in-
creased costs would not appear to have a significant impact
7-41
-------
on industry activity. No unemployment or adverse impacts
would be anticipated.
3. Model 2 - 1978. The three-year lead time has the potential
for some limited market disruption as some vehicles could
have to be removed from production due to inability to meet
the standards. This may be attenuated overall, however, by
increased production of other models.
4. Model 3 - 1983. Changes in volume and higher costs than
for either models 1 or 2 could be anticipated. The eight-
year period hypothesized as being available for plan-
ning and making adjustments for the growth of the industry
over the period would apparently be sufficient to avoid
disruptive impacts. The modest volume changes from the
baseline forecasts and the continued growth of industry would
indicate no disruptive impacts. No unemployment would be
anticipated.
7-42
-------
REFERENCES FOR SECTION 7
1. A. T. Kearney, Inc. "A Study to Determine the Economic Impact
of Noise Emission Standards in the Medium and Heavy Duty Truck
Industry, " 1974.
2. Bonder, E. K. and W. N. Patterson. "The Technology and Cost
of Quieting Medium and Heavy Trucks," BBN Report No. 2710,
1974.
3. Fax, G. 1C. "Costs of Operating Quiet Trucks, " BBN Tech Memo
No. 190, 1974.
4. Oil and Gas Journal Petroleum Publishing Co., Tulsa, Okla.,
March 11, 1974.
5. U.S. Department of Commerce, Bureau of the Census, "1972
Truck Inventory and Use Survey" (magnetic tape), 1972.
7-43
-------
SECTION 8
TRUCK ACOUSTIC ENERGY CHANGES AND LEAD TIME KEQUIREMENTS
This section examines the offoels of possible alternative new truck
noise standards, using the three models described earlier, to
endeavor to ascertain (1) the change in acoustic energy generated
by the future truck population and (2) the projected lead times to
achieve the varying modifications in production line truck design.
FUTURE CHANGES IN ACOUSTIC ENERGY LEVELS
The effects of possible alternative new truck noise standards as
shown throughout the three models and depicted in Table 8-1 on the
future acoustic energy generated by trucks with a GVWR in excess
of 10, 000 pounds are analyzed in this study. Taken into account are
the distributions of trucks likely to be in use in future years, by
gross vehicle weight rating, type of engine, age, and annual mileage.
This makes it possible to estimate the possible change in the future
acoustic energy from such trucks along typical highways.
TABLE 8. 1
ALTERNATIVE PRODUCTION NOISE LIMITS, dB(A)
New Truck
Model
Year
1977
1978
1979
1980
1981
1982
> 1983
Option
Gasoline
83
80
80
80
75
75
75
1
Diesel
83
80
80
80
75
75
75
Option
Gasoline
83
83
80
80
75
75
75
8-1
2
Diesel
83
83
83
83
80
80
75
Option
Gasoline
83
83
83
83
80
80
75
3
Diesel
83
83
83
83
80
80
75
-------
Data utilized in development of the models used are premised on
the following: that for any given calendar year, the truck generated
acoustic energy along a typical highway will be the "mileago-
weighted" summation of the product of (a) the acoustic energy
produced by each category and model year of truck, (b) the number
of such trucks registered, and (c) the annual mileage such trucks are
driven. Annual mileage is explicitly considered because it affects
the frequency with which a truck of a given category and age is
encountered on the highway. For the purposes of these calculations,
it is assumed that no truck noise control retrofit program is in
effect, so that each truck produces the same noise level over its
entire lifespan.
Thus, to assess the impact of alternative regulatory options on
future changes in the acoustic energy generated by trucks, it will
be necessary to know:
1. The mean peak noise level produced on the highway by truck
model year for each category of truck
2. The total truck production by truck model year for each cate-
gory of truck
3. The fraction of trucks still in use as a function of truck age
for each category of truck
4. The average annual mileage as a function of truck age for each
category of truck.
Each of these aspects, as it is related to calculation of the acoustic
energy generated by trucks for any future calendar year, will be
considered.
8-2
-------
The mean peak noise levels, measured at 50 feet from tbe high-
way, which are projected to be produced in the future by various
categories of trucks traveling at highway speeds are summarized in
Table 8-2 as a function of the new truck noiso levols considered in
the three alternative models.
TABLE 8. 2
MEAN PEAK NOISE LEVEL AT 50 FEET
Highway Noise Levels
Regulated
New Truck
Noise Level
None
Model 1 (83 dB(A))
Model 2 (80)
Model 3 (75)
Medium Duty
Gasoline Diosol
84 dR(A) 87 (lli(A)
84 H4
82 82
79 79
lloavy
Gasoline
87 dH(A)
H4
82
79
Duty
DifiHOl
8!)dli(A)
H4
82
79
The highway noise levels assumed for all unregulated trucks are
mean noise levels computed from measurements obtained for EPA
by contractors. Noise levels assumed for future regulated new trucks
reflect the fact that, as propulsion noise of trucks is reduced by new
truck noise regulation, tire noise will constitute an increasingly lar-
ger contribution to a truck's highway noise level.
The total new truck production projected for truck model years
are summarized in Table 8-3. Total figures for 1961 through
1972 are actual production figures reported by the Motor Vehicle
Manufacturers Association (MVMA), excluding buses and exported
trucks, but including imported trucks from Canada (Reference 1).
The truck production figures for 1960 and before are weighted
sums of previous production figures adjusted in accordance
8-3
-------
with the truck survival rate model described below to produce the
estimated number of such trucks still in use as of 1972. Produc-
tion figures for 1973 and beyond are based on estimates of truck
production growth rates (Reference 2). For example, it is assumed
that medium duty gasoline engine truck production will grow by 1.4%
per year and that heavy duty diesel engine truck production will grow
by 4. 3% per year.
The fraction of trucks still in use as a function of truck age can be
determined by generating a survival rate model for each category of
trucks. Truck production data (Reference 2) and registration data
(Reference 3) have been used to develop a truck survival rate curve
for heavy duty diesel engine trucks. This survival rate curve is
shown in Figure 8-1. For other categories of trucks, the Census
truck registration data does not correspond well with the MVMA
truck production data. For example, the MVMA reports that in 1971,
193,000 medium duty gasoline engine trucks were produced (exclud-
ing buses and exports but including imports from Canada). The 1972
Census data, however, show that 295,000 such trucks were regis-
tered. Thus 53% more trucks were registered than were produced.
In view of the fact that all medium duty gasoline truck-tractors appear
as heavy duty trucks in the Census data, it has been concluded that
a substantial number of trucks with GVWR below 10, 000 Ibs are prob-
ably appearing as medium duty trucks in the Census data. Because of
this type of inconsistency in the truck production versus registration
data, the truck survival rate obtained for heavy duty diesel engine
8-4
-------
TABLE 8-3
/.IHltAl. PRODUCTION-OF TRUCKS t IN THOUSANDS)
f-'oclel
Year
<1960
1961
1962
1963
1964
1965
1966
1967
' 1968
1969
1970
1971
1972
1973
1974
1975
1976 .
1977
1978
1979
1980
1981
1982
1983
1984
1985
1.986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
Medium
Gasoline
1473
. 177
211
222
205
228
228
189
199
219
178
193
245
198
200
202
204
207
210
213
216
219
222
225
229
232
•234.
237
241
244
248
251
255
258
262
266
270
274
277
281
Duty
Die sol
1
1
3
4
5
9
6
5
5
3
3
3
3
3 .
3
3
3
3
.3
3
3
3
3
3
3
4
4
. 4
4
4
4
4
4
4
4
4
4
4
4
4
Heavy
Gasoline
427
34
30
39
36
41
45
39
42
41
40
38
39
40
40
40
40
39
3*8
38
39
39
39
39
39
39
38
38
38
37
37
36
• 35
34
33
32
33
34
36
37
Duty
Diesel
124
24
35
43
47
63
77
64
70
90
B«
9H
126
133
144
155
165
174
185
195
205
214
225
236
248
260
274
288
302
317
333
350
367
385
. 404
425
443
462
481
502
8-5
-------
trucks has been assumed to apply to all other categories of trucks
as well.
The average annual mileage for various categories of trucks as
a function of truck age were also obtained from projections based
on the Truck Inventory and Use Survey Data. Table 8-4 shows the
projected annual mileage per truck for each category being consid-
ered as a function of the age of the truck.
150
10 15
Truck Age (Years)
Figure 8-1 Percentage of Heavy Duty Diesel Trucks Surviving as
a Function of Age.
Discussion of the Truck Inventory and Use Survey Data and the
analysis used in obtaining the acoustic energy generated by trucks,
8-6
-------
the total and components of the truck population, the survival rato,
and the annual mileage estimates for trucks may ho found in Appendix
O.
TABLE 8-4
ANNUAL MILEAGE PER TRUCK (IN THOUSANDS)
Acie °f
Truck
1 Year
2
3
4
5
6
7
8
9
10
• i 11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Medium
Gasoline
23
20
16
13
11
10
9
8
7
7
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
Duty
Diosol
30
27
24
22
19
17- ,
15
13
12
11
10
9
' 8
7
. 7
6
5
5
5
5
5
5
• 5
5
5
Heavy Duty
Gasoline Dic.s-"'1
33
29
25
21
18
16
15
13
12
10
9
8
7
6
6
5
5
4
4
3
3
3
3
3
3
73
67
61
55
50
45
40
37
34
31
28
25
22
20
18
16 ,
15
14
13
12
12
11
10
10
10
The results of this study of the projected changes in the acoustic
energy generated by trucks with GVWR in excess of 10, 000 Ibs are
shown in Figure 8-2. The acoustic energy level refers to the
1972 acoustic energy of such trucks. Note that for any new truck
regulation, the increasing truck population produces an increase in
8-7
-------
acoustic energy level of approximately 1 dB every 5 years. On the
other hand, with all of the three models employed for this study, the
the acoustic energy level continues to decrease until approximately
1992. Actually, as older, noisier trucks are retired, the individual
noise level of the average truck on the highway will continue to
decrease until about the year 2000. IFowever, the assumed growth
rale in new truck production eventually outweighs the rate of older,
noisier 1 rucks being retired, causing the acoustic- energy level to
begin increasing again tn about 1995. finally, note that both models
2 and 3 indicate nearly identical results. This is because the dom-
inant contribution to the acoustic energy level comes from heavy
duty diesel engine trucks that are regulated similarly in both models
2 and 3. The maximum difference in acoustic energy level between
models 1 and 3 is about 1 dB, which occurs around 1985.
In assessing the relative merits of alternative new truck noise
levels in terms of the acoustic energy generated, it is important to
observe how the truck population component for a given production
period in years builds up and/or decays as a function of calendar
year. Figures 8-3 through 8-5 show these results for new truck pro-
duction in the context of the three models studied. It is also instruc-
tive to note the total truck-miles driven by the various truck population
components as a function of calendar year. This relationship is shown
in Figure 8-6 in the context of model 3. A comparison of Figure
8-6 with Figure 8-5 reveals that the total truck-miles contribution
of a given truck population component decays more rapidly than its
contribution to total truck population.
8-8
-------
2000
Figure 8-2 Changes in Mlleaee-Weifchted Acoustic Energy Level.
-------
o
3
f
<-•
o
1975
1980
1935
1S90
1935
2000
Figure 8-3 Truck Population Comoonents bv Truck Model Years - Model 1
-------
00
2000
Figure 8-4 Truck Population Components by Truck Model Years - Model 2
-------
6
-------
T
u> t
1970
1975
1980
1985
Calendar Year
1990
1995
2000
8-6 Breakdown of Total Truck-Miles by Truck. Model Years - Mod"!
-------
LEAD TIME REQUIREMENTS
Thr juM'iod between the introduction of a design goal Cor a produrl,
and the time the design goal is met is often termed "lead time."
The actual length of time is directly related to the complexity and
the resources available to implement the new designs. In general
the sequence of events involved in modifying a new production truck
is as follows. First, a design goal is usually selected on the basis
of market or legislative pressure. The engineering groups responsi-
ble for the respective truck components then examine the design prob-
lem for possible solutions. Promising solutions are then either in
a prototype version or modeled for testing and evaluation. Finally,
one or more solutions are selected for complete product analysis and
testing. This often includes a field test of durability.
The complexity of noise control design changes may be classified
into two basic modes of engineering operations. For changes in the
peripheral engine system (such as mufflers, air filters, cooling fans,
and the like), noise control solutions would be implemented by modi-
fying present production trucks; i.e., by specifying certain exhaust
systems, air filters, fan configurations, and pulley sizes. Such mod-
ifications are made via an "engineering change order. " For changes
in the basic frame or cab configuration (such as partial enclosures
or larger radiators), a complete design sequence could well be re-
quired, including some reliability testing.
8-14
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The lead time required for either category of design changes var-
ies with the complexity of the change and available staff, but some
estimates may be made. It would appear that from 30 to 180 days
are necessary for most manufacturers for an engineering change
order to be completed. The length of time required for a major new
design varies for normal production and assembly planning from 1
to4 years. In general, enclosing the engine could require cab modi-
fications that could take as much as a year for each cab model of-
fered. Discussions with manufacturers indicate That a 1-year lead
time is adequate in terms of being nondisruptive of regular produc-
tion, but that extensive overall truck redesign could require up to
a full 4-year period. An example of a 4-year development cycle
is given in Reference 4. Figure 8-7 has been reproduced from this
reference. Concurrent development of similar noise control options
could shorten the overall lead time for a complete product line.
PROPER SEdUEKCE AHO TIMIM6
TO PRODUCE A QUALITY TRUCK
UlLLLiliLJ I! I! 11
ttmomtin
DUWMS
KOTO-
TYPES
tara
— FOUR YEARS -
Figure 8-7 Estimated Lead Time for Redesigning a Truck.
Source; Reference 4.
An additional factor in lead time is engineering staff size and ca-
pability. All truck manufacturers have an engineering staff whose
8-15
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size is generally proportional to sales volume. Consequently, the
larger companies have bigger staffs with more specialized capabil-
ities, including staff specialized in noise control. The smaller com-
panies may be dependent on their vendors for noise control to a
greater degree than will the larger firms. Also, smaller companies
will tend to rely on copying the noise control designs used by the
more advanced companies or those described in the open literature.
The increased lead time over large firms required by the smaller
manufacturers is compensated for in part by the relatively fewer
models they produce. Thus, while a large firm may have eight dif-
ferent cab designs to change, the small firm may have only three
cab designs to change.
Varying lead times have been studied in terms of the noise levels
for new trucks considered in the three models' scenarios. At each
noise level, the complexity of the change and the capabilities required
to achieve certain noise analyses and reductions are discussed.
More than 30% of present production trucks have noise levels less
than 83 dB(A). Although this is a significant number of trucks re-
flecting some manufacturers' apparent efforts to comply with the State
of California limit of 83 dB(A), which becomes effective in 1975,
many models must be fitted with quieter exhaust systems, cooling
fans, and engine noise control packages. All these modifications can
be implemented by engineering change orders. The necessary engine
exhaust systems appear to be available. Noise control packages
are also apparently available at this time for those engines that would
require them to meet the California standard.
8-16
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The primary design problem will be to modify the cooling fun.
All truck manufacturers purchase the fans from vendors; conse-
quently, in an attempt to quiet fan noise, they will typically buy a
"quiet" fan. However, fan noise is as much a function of a fan's
environment as its design. At the present time, certain technique s
are available that consistently reduce cooling fan noise; i.e., using
larger diameter, slower rotating fans with proper shrouding. In ad-
dition, the radiator shutters may require replacement by a bypass
type of water temperature control, or be operated in conjunction with
a thermostatically controlled fan such that the fan never operates with
the shutters closed.
Incorporating the modifications that may be necessary to continue
producing essentially the same trucks now being produced but satis-
fying the 83 dB(A) noise level appears to be feasible within 1 to 2
years from the date of promulgation of an 83 dB(A) standard.
Most truck manufacturers indicate that nationwide compliance with
an 83 dB(A) level could be achieved by the 1976 model year, with
no significant disruptions in production. This was assuming that new
truck noise regulations were promulgated in the fall of 1974. There
are indications, however, that even without a Federal standard of
83 dB(A) in 1974, the majority of trucks produced in the 1976 model
year will be able to meet that level.
Of the trucks measured for sound level, 1% are now at noise
levels under 80 dB(A). Engine noise is a prime candidate in the
quieting strategy for meeting this level, and certain currently popular
diesel engines will likely require some sort of enclosure to meet
8-17
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it. Thus, the lead time necessary for a given truck to be produced
which meets the 80 dB(A) level will vary depending on the engine.
To accommodate these differences, truck lead times will bo dis-
cussed in terms of gasoline engines, "quiet" diesel enginos, and
"noisy" diesel engines.
For gasoline engines, which power 65% of all new medium and
heavy duty trucks, engine and exhaust noise do not appear to be
significant problems and no major cab redesign is anticipated, other
than possible modification of the radiator. Thus, gasoline engine
new trucks could reasonably be assumed to be able to be quieted
to meet an 80 dB(A) level in the same time span as for an 83 dB(A)
level, that is, 1 to 2 years from the effective regulation date.
The quieter diesel engines, which are incoporated in about 23%
of the trucks currently produced, could need noise control covers
or kits to obtain the necessary reduction in engine noise. Such kits
are not presently available for all these engines. Some development
work could be required for this effort; however, it is not believed
that this would be a major development program, but rather the adap-
tation of similar kits from one engine model line to another, or the
development of acoustically treated covers and panels. Two to three
years appear adequate for such comprehensive development, which
would appear to encompass all models of vehicles now being produced.
During this period it may also be necessary for some truck manufac-
turers to apply underhoodacoustic treatment. Similarly, some cool-
ing system designs could require a modest refinement effort of from
8-18
-------
2 to 3 years. Exhaust systems are now generally available to meet
the 80-dB(A) level. All these measures can, therefore, be relatively
easily accomplished to provide the necessary production capacity
parts and installation within a maximum of 3 years of promulgation
of a regulation requiring 80 dB(A).
The noisier diesel engines, which constitute about 12% of current
truck production, will most likely require cab redesign in the form
of a partial engine enclosure, or development of engine quieting tech-
niques to reduce engine noise. This would be considered a major
redesign and a design sequence similar to that illustrated in Figure
8-7 would be necessary. Cab redesign would probably include
enlarging the cab tunnel or underhood area to accommodate sound-
absorptive treatment and larger radiators. Accordingly, about 4
years could be needed to develop a new cab, keeping within a normal,
that is non-disruptive, production planning and implementation cycle.
Most manufacturers offer several truck models each of which could
require individual major redesign. Unlike automobiles, such truck
redesign is not normally done annually; however, by staggering design
efforts at, say, one year intervals, three cabs could be redesigned
in about 6 years with more efficient utilization of engineering staff
than would be possible with parallel efforts and, consequently, even
less cost impact than would reasonably be expected to result if a
shorter period of time were required.
An alternative solution to truck redesign would be for the manu-
facturers of noisy engines either to quiet them with noise control
covers or kits or with structural or combustion modifications. One
8-19
-------
major engine manufacturing company indicated that if quiet engines
were required, it would provide them to its customers. Assuming
that this company does have the ability to quiet its engines within a
3-year lead time, then major cab redesign would not be required
and the lead time for trucks with these engines would be the same
as for the quieter diesel engines; i.e., 3 years from the date of
promulgation of the 80 dB(A) standard.
Freightliner currently is operating on the highway a 72 dB(A)
prototype developed under the DOT Quiet Truck Program. Other
manufacturers have built prototype test trucks with overall noise
levels as low as 72 dB(A), but have not operated them extensively on
the highway.
Quieting strategies and lead times which may be necessary for
limiting truck noise to 75 dB(A) are again appropriately discussed
according to whether new production trucks are powered by gasoline
engines, quiet diesel engines, or noisy diesel engines. Some diesel
engines (approximately 5% of the current total new truck production)
are only slightly noisier than gasoline engines. Quieting techniques
could be developed using present production line technology to reduce
their engine source level to less than 70 dB(A). These engines could
then be used to power trucks built without enclosures. It is believed
that the nondisruptive lead time would be on the order of that for
80 dB(A) trucks, but, with added time allowed to develop the engine
noise control covers and kits, mufflers, and fan systems. This as-
sumes 2 years to refine certain mufflers to obtain a 68 dB(A) source
8-20
-------
lovol, a concurrent one-year period to develop engine noise control
kits, and a two-year development time by manufacturers for the fan
and all other systems. If a maximum total lead time for both large
and small manufacturers of about six years was allowed, following
promulgation of a 75-dB(A) standard, no significant disruptive effects
would be anticipated within the truck manufacturing or parts industry.
That is, small manufacturers could perform three successive model
changes in six years and larger firms with additional resources could
do some of the work concurrently.
Noisy dies el engines will in all likelihood require enclosures.
Allowing two additional years for enclosure development beyond that
required to meet 80 dB(A), the redesign of current production noisy
trucks to meet a 75-B(A) level could take about 8 years. However,
new developments in diesel engine technology, such as better covers
for existing engines or improved structural design, could reduce this
lead time considerably.
In summary, the lead times required by truck manufacturers to
quiet their products are best classified by the engine used in the
truck. The most difficult quieting problem, and consequently that
contributing most to establishing the production lead time, is engine
structural noise. Table 8-5 lists the estimated lead times required
by all truck manufacturers to ensure that all trucks produced will
meet the specified noise levels. Lead times are defined as starting
from the date of promulgation of a standard.
8-21
-------
TABLE 8-5
ESTIMATED LEAD TIMES FOR TRUCK PRODUCTION
Noise Level Gasoline Engines
"Quiet"
Diesel Engines
"Noisy"
Diesel Engines
83 dB(A)
80 dB(A)
75 dB(A)
1-2 years
3 years
6 years
1-2 years
3 years
6 years
2 years
6 years
8 years
8-22
-------
REFERENCES FOR SECTION 8
1. "1973 Motor Truck Facts," Motor Vcluclo Manufacturers Asso-
ciation, 1973.
2. "A Study to Determine the Economic Impact of Noise Emission
Standards in the Medium and Heavy Duty Truck Industry, " A.
T. Kearney Report (Draft), April 1974.
3. "1972 Truck Inventory and Use Summary" (Magnetic Tape),
U. S. Department of Commerce, Bureau of the Census, 1972.
4. "Proceedings of the Conference on Motor Vehicle Noise," General
Motors Corporation Report, June 1973.
8-23
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SECTION 9
MEASUREMENT METHODOLOGY
INTRODUCTION
The procedure for determining whether or not a new truck
complies with a prescribed noise level involves two basic elements,
namely: a method for performing a test on a selected truck and
a method for selecting trucks. This section deals with the testing
of selected trucks, while section 10 discusses a possible selection
process.
Several tests currently in existence were considered by the
E. P. A. as methods for testing new production trucks. The Society
of Automotive Engineers test designated SAE-J366-b seems
to be the only test available with a sufficient data base to permit
its consideration as a test that could be utilized effectively
in the near term without extensive further evaluation as to its
efficacy. It is described in detail in the following paragraphs.
In addition to the Low Speed High Acceleration Test, (which is
the only test which will be used for regulatory purposes), other
tests have been considered and these are presented along with the
the Low Speed High Acceleration Test to solicit comment and to ob-
tain suggestions which could be useful. In particular a High Speed
Sound Emission Test is described. This is a modification of the
SAE J 57. It is described in some detail because, should a high
speed truck noise test be needed this test or a modification of it
could be utilized.
9-1
-------
LOW-SPEED, HIGH ACCELERATION TEST
Introduction
This test establishes the procedure, environment, and in-
strumentation for determining the maximum exterior sound level
for motor trucks, truck tractors, and buses, when they are oper-
ated under conditions of low speed (under 35 MPH)and high acceler-
ation.
In s t r um ent at ion
The following instrumentation shall be used, where applica-
ble, for the measurement required.
1. A sound level meter which meets the Type 1 requirements of
of ANSI SI. 4-1971, Specification for Sound Level Meters.
2. As an alternative to making direct measurements using a sound
level meter, a microphone or sound level meter shall be used
with a magnetic tape recorder and/or a graphic level record-
er or indicating meter, providing the system meets the re-
quirements of SAE J184.
3. A sound level calibrator.
4. An engine-speed tachometer.
Test Sites
1. A suitable test site shall consist of a level open space free
of large reflecting surfaces, such as parked vehicles, sign-
boards, buildings, or hillsides, located within 100 ft (30 m)
of either the vehicle path or the microphone. See Fig. 9-1.
2. The microphone shall be located 50 ft (15 m) from the center-
line of the vehicle path and 4 ft (1.2 m) above the ground
plane. The normal to the vehicle path from the microphone
9-2
-------
Zone In Which
To Reach
Max Rated RPM
Dimension* In
Feet (Meter*)
FIGURE 9-3. MINIMUM UNIDIRECTIONAL TEST SIT*
-------
shall establish the microphone on the vehicle path.
3. An acceleration point shall be established on the vehicle path
50 ft (15 m) before the microphone point.
4. An end point shall be established on the vehicle path 100 ft (30 m)
from the acceleration point and 50 ft (15 m) from the micro-
phone point.
5. The end zone is the last 40 ft (12 m) of vehicle prior to the
end point.
6. The measurement area shall be the triangular area formed by
the acceleration point, the end point, and the microphone
location.
7. The reference point on the vehicle, to indicate when the ve-
hicle is at any of the points on the vehicle path, shall be the
front of the vehicle except as follows:
a. If the horizontal distance from the front of the vehicle
to the exhaust outlet is more than 200 in (5080 mm),
tests shall be made using both the front and rear of the
vehicle as reference points.
b. If the engine is located rearward to the center of the chas-
sis, the rear of the vehicle shall be used as the reference
point.
8. During measurement, the surface of the ground within the mea-
surement area shall be free from powdery snow, long grass,
loose soil, and ashes.
9. Because bystanders have an appreciable influence on meter re-
sponse when they are in the vicinity of the vehicle or micro-
phone, not more than one person, other than the observer
9-4
-------
reading the meter, shall be within 50 ft (15 m) of the vehicle
path or instrument, and that person shall be directly behind
the observer reading the meter, on a line through the micro-
phone and the observer.
10. The ambient sound level (including wind effects) coming
from sources other than the vehicle being measured shall
be at least 10 dB(A) lower than the level of the tested vehicle.
11. The vehicle path shall be relatively smooth, dry concrete or
asphalt, free of extraneous material such as gravel.
Procedure
1. Vehicle operation - full throttle acceleration and closed
throttle deceleration tests are to be used. A beginning engine
speed and proper gear ratio must be determined for use dur-
ing measurements.
2. Select the highest rear axle and/or transmission gear
("highest gear" is used in the usual sense; it is synonymous
to the lowest numerical ratio and an initial vehicle speed
such that at wide-open throttle the vehicle will accelerate
from the acceleration point):
3. a. Starting at no more than two-thirds (66%) of maximum
rated or of governed engine speed.
b. Reaching maximum rated or governed engine speed
within the end zone.
c. Without exceeding 35 mph (56 km/h) before reaching the
end point.
4. Should maximum rated or governed rpm be attained before
reaching the end zone, decrease the approach rpm in 100
rpm increments until maximum rated or governed rpm is
9-5
-------
attained within the end zone.
5. Should maximum rated or governed rpm not be attained until
beyond the end zone, select the next lower gear until
maximum rated or governed rpm is attained within the end
zone.
6. Should the lowest gear still result in reaching maximum rated
or governed rpm beyond the permissible end zone, unload
the vehicle and/or increase the approach rpm in 100 rpm
increments until the maximum rated or governed rpm is
reached within the end zone.
7. For the acceleration test, approach the acceleration point
using the engine speed and gear ratio selected in paragraphs
1-6 and at the acceleration point rapidly establish wide-open
throttle. The vehicle reference shall be as indicated in para-
graph 7. Acceleration shall continue until maximum rated
or governed engine speed is reached.
8. Wheel slip which affects maximum sound level must be
avoided.
9. For the deceleration test, approach the microphone point
at maximum rated or governed engine speed in the gear
selected for the acceleration test. At the microphone point,
close the throttle and allow the vehicle to decelerate to one-half
of maximum rated or of governed engine speed. The vehicle
reference shall be as indicated in paragraph 7. If the ve-
hicle is equipped with an exhaust brake, this deceleration test
is to be repeated with the brake full on immediately following
closing of the throttle.
9-6
-------
Measurements
1. The meter shall be set for "fast" response and the A-
weighted network used.
2. The meter shall be observed during the period while the
vehicle is accelerating or decelerating. The applicable reading shall
be the highest sound level obtained for the run. The observer shall
rerun the test if unrelated peaks should occur due to extraneous
ambient noises. Readings shall betaken on both sides of the vehicle.
3. The sound level for each side of the vehicle shall be the aver-
age of the two highest readings within 1 dB of each other. Roport
the sound level for the side of the vehicle with the highest readings.
General Comments
1. Measurements shall be made only when wind velocity is
below 12 mph (19 km/hr).
2. Technically trained personnel shall select the equipment to
be used for the test measurements and the tests shall be conducted
only by persons trained in the techniques of sound measurement.
3. Proper usage of all test instrumentation is essential to obtain
valid measurements. Operating manuals or other literature furn-
ished by the instrument manufacturer shall be referred to and shall
be the principal reference for both recommended operation of the
instrument and precautions to be observed, except where they may
be in conflict with theE.P;. A< prescribed procedures, in which case
the latter shall govern. Specific items to be considered are:
9-7
-------
a. The effects of ambient weather conditions on the performance
of the instruments (for example, temperature, humidity, and baro-
metric pressure) should be taken into account.
b. Proper signal levels, terminating impedances, and cable
lengths should be maintained on all multi-instrument measurement
systems.
c. The effect of extension cable and other components should be
taken into account in the calibration procedure. Field calibration
shall be made immediately before and after each test sequence.
Internal calibration means is acceptable for field use, provided
that external calibration is accomplished immediately before or
after field use.
4. Vehicles being tested shall not be operated in a manner such
that the break-in procedure specified by the manufacturer
is violated.
References
Suggested reference material is as follows:
ANSI SI. 1-1960, Acoustical Terminology
ANSI SI. 2-1967, Physical Measurement of Sound
ANSI SI.4-1971, Specification for Sound Level Meters
Applications for copies of these documents should be addressed to
the American National Standards Institute, Inc., 1430 Broadway,
New York. New York 10018.
9-8
-------
MODIFICATION TO SAE-J366b
The process of developing a suitable test for truck noise emission
is a continuing one. The present SAE J366b is the third stage in the
SAE effort, the first.and second stages being labelled SAE J366 and
SAE J388a. A fourth modification, suggested by the National Bureau
of Standards, is described in reference (1). In the following sections
some of the difficulties identified by the U.S. E. P. A. associated with
SAE J366b are discussed, and considerations are presented which
may be helpful in the generation of the next modification, or in the
development of other future tests.
Nature of the Source
As the truck, under test, traverses the vehicle path (Fig. 9.2.3.1)
it behaves as a variable acoustic source. For example, exhaust noise,
engine surface radiated noise and cooling fan noise all vary with time
during the test. This implies that during the test, the truck (regarded
as an acoustic source) is changing its acoustic power output, its
directivity pattern and its spectrum as a function of time and conse-
quently also as a function of its position. A truck under test is a
complicated acoustic source and the 'optimum manner to charac-
terize its acoustic behavior would appear to warrent further study.
Modifications
Several areas in the present SAE J366b standard which appear
worthy of further study are:
9-9
-------
Geometry; The total length of path available to the test vehicle
is 100 feet. It may be that increasing this distance, as well as
that allotted to the end zone, would reduce the number of trials
required to achieve maximum engine rpm inside the presently de-
fined end zone.
It is necessary to know where a vehicle is located when it is
radiating sound during a test. This information is needed to prop-
erly combine and/or interpret sound level readings taken simultan-
eously at several microphones. In addition, a time base is needed
to define simultaneity for multimicrophone data. For example, in
the SAE J366b Standard a constant power source at the beginning of
the end zone produces about a 2. 8-dB higher sound level reading at
the test microphone than the same source located at the far end
">f the end zone. Knowledge of truck position would minimize this
type of discrepancy. Position /time measurements are also neces-
sary to establish the directivity characteristics of the truck radiated
noise,
Microphones. The measurement of a moving variable source,
such as a truck moving on a straight path, requires more than one
microphone if significant results are to be obtained. For example,
it it it? assumed that the sound levels anywhere on a line parallel
to and spaced 50 ft away from the line of travel of a truck is the
significant quantity for truck noise measurement, then it is clear
that a single fixed microphone will see only what the source radiates
at a single angle at a single distance at a single instant of time.
At that same instant of time the source directivity pattern may be
9-10
-------
such as to radiate a higher intensity of sound in some other direction
than that of the microphone. Since the directivity pattern can be
changed with time, the microphone may never have detected this
higher intensity if it had occurred. A suitable ensemble of micro-
phones would have detected it. Another case could occur in which the
single microphone would not see a maximum directivity pattern; that
is, if the maximum occurred in the angular range, 0 to 45 degrees
•where the angle is measured from the line of travel to the maximum.
This would be true for both the front and rear of the truck.
Of the 180 degrees of horizontal directivity pattern that exists
on one side of a truck, the SAE J366b microphone looks at only 90.
That is, only one half of the angular spread of the directivity pattern
is examined. Trucks are not omnidirectional sources, as the data in
references 1 and 2 show. The question of how best to deploy a multi-
microphone test ensemble requires attention. This includes a study
of the optimum number of microphones as well as their three-
dimentional spatial distribution.
Test Site
At the test site, there certain parameters not adequately
covered in SAE J366b. These are:
1. The accoustical characteristics of the surface of the site.
Acoustically "hard11 surfaces such as concrete tend to absorb
less acoustic energy than soft ones, such as dirt, grass cover,
or fresh asphalt. Also, acoustic interference effects are
different for these cases. It, therefore, is desirable to specify
9-11
-------
the surface of the test site so that this source of error is
eliminated.
2. There have been indications that, when the test site surface
deviates from planarity, anomalous acoustical results are
obtained. This question requires further study and a deter-
mination should be made of the degree of flatness necessary
for accurate acoustic measurements.
3. The air temperature at the sites as well as the barometric
pressure and humidity all affect the acoustic levels measured
in any given test. An effort should be made to develop suitable
correction procedures for these variations.
4. An additional effect is that of temperature gradient. The
size of this effect is not presently known in truck noise emis-
sion tests. It could be important, especially at sites where
the surface is asphalt. In the summer the hot asphalt surface-
could produce a substantial temperature gradient. The gra-
dient tends to bend sound "rays" and could produce different
readings at a test microphone than if there were no gradient.
5. Noise emission tests are presently conducted in the open air.
This is satisfactory from an acoustic point of view. How-
ever, it makes the test schedule weather dependent. The
usefulness of developing a practical weatherproof structure
in which a passby test could be performed is suggested for
consideration.
6. The instrumentation delineated in SAE J366b has been largely
superseded by rapid advances in this field. It is consequently
9-12
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dated as it implies manual data collection and data pro-
cessing. These techniques can be updated and automated by
the use of digital computers. It should be possible to have
the test result displayed within seconds after the truck has
driven past the ensemble of test microphones.
HIGH SPEED SOUND EMISSION TEST PROCEDURE
This is a test procedure for measuring the sound level produced
by tires intended primarily for highway use on motor trucks, truck
tractors, trailers and semitrailers, and buses. The procedure pro-
vides for the measurement of the sound generated by tires, mounted
on a motor vehicle at specified tire load and operated at 50 mph (80
km/h).
Specifications for the instrumentation, the test site, and the opera-
tion of the test vehicle are set forth to minimize the effects of extran-
eous sound sources and to define the basis of reported levels.
Instrumentation
The following instrumentation shall be used:
1. A sound level meter that satisfies the type 1 requirements of
ANSI SI. 4-1971, Specifications for Sound Level Meters; or
2. As an alternative to making direct measurements using a sound
level meter, a microphone or sound level meter shall be used
with a magnetic tape recorder and/or a graphic level recorder
or indicating meter, providing the system meets the requirements
of SAE J184, with "slow" response specified in place of "fast"
response.
9-13
-------
3. An acoustical calibrator for establishing the calibration of the
sound level meter and associated instrumentation.
4. An anemometer.
Test Site
The test site must be located in a flat area free of reflecting surfaces
(other than the ground), such as parked vehicles, trees, or buildings
within 100 ft (30 m) of the measurement area.
The vehicle path shall be relatively smooth, semipolished, dry, port-
land concrete free of extraneous surface material.
The microphone shall be located 50 ft (15 m) from the centerline of
the vehicle path at a height of 4 ft (1. 2 m) above the ground plane.
The normal to the vehicle path from the microphone shall establish the
microphone point on the vehicle path. See Fig. 9-2.
The test zone extends 50 ft (15 m) on either side of the microphone
point along the vehicle path. The measurement area is the triangular
area formed by the point of entrance into the test zone, point of exit
from the test zone, and the microphone.
The measurement area shall be surfaced with concrete, asphalt or
similar hard material, and in any event shall be free of powdery
snow, grass, loose soil, crashes, or other sound-absorbing materials.
The ambient sound level (including wind effects) at the test site shall
be at least 10 dB below the level of the test vehicle operated in accord-
ance with the test procedure.
The wind speed in the measurement area shall be less than 12 mph
(19 km/hr)
9-14
-------
Dimensions In
Feet (Maters)
FIGURE 9-2 TEST SITE.
-------
Vehicle
The vehicle shall be a motor vehicle equipped with the set of tires it
will have when it enters commerce, that is, when it is delivered
to the first person who in good faith purchases the motor vehicle for
purposes other than resale. The tire specifications must be recorded
for each tire.
Tires
The tires shall be inflated to the maximum pressure and loaded
to the maximum load specified by the Tire and Rim Association for
continous operation at highway speeds exceeding 50 mph (80 km/h).
If local load limits will not permit a full rated load, the test may
be conducted at the local limit with inflation pressure reduced to pro-
vide a tire deflection equal to the maximum load and inflation pressure,
provided the load is not less than 75% of the maximum rated load.
hocause this may cause small differences in (sound) levels, such levels
may not be reported absolute unless they are identified with the percent
of load used. Sound levels obtained when the loading is (P) percent
must be corrected by adding the quantity \O Lo& ffo° \
t< the measured values .
Procedure
The test vehicle shall be operated in such a manner (e. g. , coasting)
that the sound level due to the engine and other mechanical sources
IH minimized throughout the test zone. The vehicle speed at the micro-
phone point shall be 50 mph (80 km/h).
The sound level meter shall be set for "slow" response and the A-
weighting network. The observer shall record the highest level attained
9-16
-------
during each pass of the test vehicle, excluding readings where known
acoustical interferences have occurred.
Alternatively, each pass of the test vehicle shall be recorded on
magnetic tape and subsequently analyzed with a sound level meter
and/or graphic level recorder.
There shall be at least three measurements. The number of
measurements shall equal or exceed the range in decibels of the level
obtained.
The sound level reported shall be the average of the two highest road-
ings within 2 dB of each other.
General Comments
Measurements shall be made only when wind velocity is below 12 mph
(19 km/hr).
Technically trained personnel shall select the equipment to be
used for the test measurements and the tests shall be conducted only
by persons trained in the techniques of sound measurements.
I roper usatjre of all test instrumentation is essential to obtain valid
measurements. Operating manuals or other literature furnished by
the instrument manufacturer shall be referred to and shall be the prin-
cipal reference for both recommended operation of the instrument and
precautions to be observed, except where they may be in conflict with
the EPA prescribed procedures, in which case the latter shall govern.
Specific items to be considered are:
1. Specifications for orientation of the microphone relative to the
ground plane and the source of sound should be adhered to.
9-17
-------
(Assume that the sound source- is located at the microphone
point.)
2. The effects of ambient weather conditions on the performance of
the instruments (e. g., temperature, humidity, and barometric
pressure) should be taken into account.
3. Proper signal levels, terminating impedances, and cable lengths
should be maintained on all multi-instrument measurement
systems.
4. The effect of extension cables and other components should be
taken into account in the calibration procedure. Field calibration
should be made immediately before and after each test sequence.
Internal calibration means are acceptable for field use, provided
that external calibration is accomplished immediately before or
after field use.
5. The effect of extension cables and other components should be
taken into account in the calibration procedure. Field calibration shall
be made immediately before and after each test sequence. Internal
calibration means are acceptable for field use, provided that external
calibration is accomplished immediately before or after field use.
OTHER TEST PROCEDURES
In the course of preparing this document test procedures other
than SAE J366b were considered. They included:
1. Stationary Run-Up (Idle - Maximum - Idle - IMI). In this
test the engine is initially in an idle condition. It is rapidly
accelerated by maintaining a wide open throttle and then decel-
erated by quickly closing the throttle. In this test, the engine's
9-18
-------
own intertia provides the load.
b. Stationary-Run-Up (Steady State). In this test the truck
wheels are required to drive a load. The engine is then ac-
celerated to maximum rpm and maintained there for a short
time. This type of test permits more time for conducting
the test and it does not depend upon transient peak noise
emission as in the IMI test. However, the development of
a satisfactory loading procedure, which itself does not pro-
duce noise (which could interfere with the test), is a matter
of some uncertainty. Several loading techniques have been
suggested, such as coupling an inertia load to the wheels and
at the same time jacking up the rear wheels. Another sug-
gestion is to use the vehicle's own brake as a loading device.
The use of dynamometer rollers, either free or loaded, has
also been suggested.
The possibility of performing stationary run-up tests inside
an enclosure, in order to make the procedure weatherproof,
has also been considered.
3. In addition to stationary run-up-type tests there exists the
possibility of developing a weatherproof passby test. This
entails covering a. suitable length of test track with a canopy
that can adequately shield the track from the elements. At
a certain portion of the track the heavy weather resistant
canopy is replaced by a thin, tough plastic canopy. This thin
canopy is light enough to exhibit a very small acoustic trans-
9- 19
-------
mission loss but is also strong enough to be reasonably weather
resistant. The measuring microphones are placed outside
the thin canopy at essentially the same positions they occupy
in open air testing. They too are protected by coverings
of the same thin, tough plastic.
The feasibility of developing this kind of test is by no means
means assured. However, its ultimate utility and its initial
apparent "do-ability" suggest that it should be considered
further.
All of the above tests appear to have the capability of being de-
veloped into short (approximately 2 minute) tests and this aspect of
the test development should be carefully considered.
SUMMARY
This section has presented:
1. The details of the SAE J366b noise emission test as a can-
didate for the standard test for new truck noise emission
regulation
2. Some considerations for further development of SAE J366b
3. A brief discussion on other tests considered for use in the
measurement of new truck noise
9-20
-------
REFERENCES FOR SECTION 9
1 . Ben H. Sharp, "Research on Highway Noise Measurement Silos,'
Wyle Laboratories Research Staff Report WCR 72-1,
p. 99 - 105, March 1972.
2. J. W. Thompson, "An Engineering Approach to Diesel Truck
Noise Reduction," SAE Preprint 730713. Portland, Ore. meet-
ing, August 20-23, 1973.
9-21
-------
SUCTION 10
WNI-'OIU'KMKIMT
GENERAL
Enforcement of new product noise emission standards applicable
to new medium and heavy duty trucks may be accomplished through
certification or production verification testing of vehicle configura-
tions, assembly line testing using continuous testing (sample testing
or 100% testing), or selective enforcement auditing of production
vehicles and in-use compliance programs. The predominant portion
of any certification or production verification testing and assembly
line vehicle testing can be carried out by the manufacturer and audited
or confirmed by authorized government personnel as necessary.
Any test used for certification or production verification testing,
and any test used for assembly line testing of production vehicles,
should be the same test or else correlative so that compliance may
be accurately determined. Measurement methodologies which
appear applicable both for certification or production verification
testing and any assembly line testing are the EPA Low Speed High
Acceleration and the EPA High Speed Test.
CERTIFICATION
Certification is the testing of selected prototype products by a
manufacturer or by the government in order to determine whether the
products conform to a standard. Certification serves the purpose of
verifying that a manufacturer has the technology in hand or "avail-
able" and, where required, it may be used to verify that the applied
technology will last for some period of use.
10-1
-------
Certification may involve the testing of every configuration of
a manufactuturer's production to verify whether each conforms, or
configurations may be grouped into categories with similar emission
characteristics and only selected configurations tested. The con-
figurations tested are then considered representative of the other
untested configurations in a category.
The concept of certification has associated with it tho issue of
approval by the government after a manufacturer has demonstrated
conformity through testing.
Because certification normally deals with a few prototype vehi-
les, it does not give any indication of the conformance of the manu-
facturer's product with standards. The ability of a manufacturer
to apply the technology to a prototype model does not necessarily
mean that actual production line vehicles will also conform. Veri-
fication that production models conform can be made only by actual
testing of production models.
PRODUCTION VERIFICATION
Production verification is the testing of selected pilot line (first
production) models by a manufacturer or by the government to verify
whether a manufacturer has the technology in hand and is capable
of applying the technology in a manufacturing process. The tested
pilot line models (or first production models) must conform with
the standard prior to any distribution into commerce of that model.
Production verification does not involve any formal governmental
approval or issuance of certificates subsequent to manufacturer
10-2
-------
testing, nor is any extensive testing required of the government.
Any regulations would require that prior to distribution into commerce
of any manufactured configuration, as defined within the regulations,
the configuration must undergo production verification. A vehicle
model would be considered to have been production verified after the
manufacturer has shown, based on the application of the noise
measurement tests, that a configuration or configurations of that
model conform to the standard. Production verification testing of
all configurations produced by a manufacturer may not be required
where a manufacturer can establish that the noise levels of some
configurations within a model are consistently higher than others or
are always representative of other configurations. In such a case,
the higher emitter would be the only configuration requiring verifi
cation. After initial verification manufacturers must re-verify when-
ever they implement engineering changes to their products that are
likely to adversely affect noise emissions. Additionally, further
testing on some continuing or other periodic basis of production line
products will still be necessary to ensure, with some confidence,
that all products being manufactured conform to the standards prior
to being distributed into commerce.
Production verification provides the government with confidence
that production models will conform to the standards. It also limits
the possibility that nonconforming vehicles will be distributed in com-
merce because initial testing is performed on pilot line or first
production models. Because the possibility still exists that subsequent
models may not conform, assembly line vehicle testing should be
10-3
-------
made a part of any enforcement strategy in order to determine
whether production vehicles continue to conform to the standard.
ASSEMBLY LINE TESTING
Assembly line testing of production vehicles is a process by which
vehicles, as they are completed on the assembly line, are tested to
determine whether they conform to applicable standards. This deter-
mination as to whether production vehicles comply with the standard
can be made by the use of either continuous 100% testing of newly
assembled vehicles, or testing of representative samples of newly
produced vehicles and drawing inferences with regard to the conform-
ity with the standard of other newly assembled vehicles. In the case
of the production of nominally identical vehicle configurations, which
exhibit the same or similar noise emission characteristics through
the application of the same or similar noise attentuation technology,
the use of sample testing is a realistic way of determining compliance
by other untested vehicles produced by a manufacturer.
Continuous 100% Testing
In the absence of a short, inexpensive test, 100% testing can be
costly and time consuming and in most cases unnecessary in the
absence of some justification to the contrary since sample testing
can yield the desired result. At this time, 100% testing is not pro-
posed as a primary enforcement tool; however, 100% testing may be
required should a manufacturer be discovered producing noncon-
forming vehicles.
Sample Testing
Sample testing involves the testing of a percentage of vehicles
10-4
-------
on some continuous basis or the auditing of production line vehicles
on some random basis or for cause. An auditing strategy would enable
the government to determine if production vehicles meet promulgated
emission standards and provide a deterrent to the distribution in
commerce of nonconforming products. An auditing strategy involves
the testing of a representative number of production vehicles in a
random fashion. Because the number of vehicles tested under an
auditing strategy is nominal, the cost and effort associated with imple-
mentation of such a strategy for a conforming manufacturer is only
a fraction of the cost of a program involving continuous testing because
fewer vehicles are involved.
Any sampling strategy adopted by the government would not
necessarily impose a quality control or quality assurance scheme upon
a manufacturer, but would merely audit the conformity of his products
and provide a deterrent to the distribution in commerce of noncon-
forming products.
ENFORCEMENT ACTION
The prohibitions in the Act would be violated where the manufac-
turer fails to properly certify or verify the conformance of production
vehicles, where it is determined on the basis of assembly line testing,
or other information, that nonconforming production vehicles are
knowingly being distributed into commerce, or where the manufac-
turer fails to comply with an Administrator's order specifying appro-
priate relief where nonconformity is determined.
10-5
-------
REMEDIES
In addition to the criminal penalties associated with violations
of the prohibitions of the Act, which include fines and imprisonment.
the Administrator has the option of issuing an order specifying such
relief as he determines necessary to protect the public health and
welfare. Such an order could include the requirement that a
manufacturer recall products distributed into commerce not in con-
formity with the regulations, and that a manufacturer effect any
remedies whether or not the manufacturer had knowledge of the non-
conformity. Such recall orders would be issued in situations where
assembly line testing demonstrated that vehicles of a particular
configuration had been distributed into commerce not in conformity
with the applicable noise emission standards.
LABELING
Any enforcement strategies could be accompanied by the require-
ment for labeling of products being distributed into commerce. The
label will provide notice to a buyer and user that the product is sold
in conformity with applicable regulations, that the vehicle possesses
noise attenuation devices and that such items should not be removed
or rendered inoperative. The label should also indicate the associated
liability for such removal or rendering inoperative.
inoperative.
IN-USE COMPLIANCE
If the goal of protecting the public health and welfare is to be
fully achieved, the noise levels of vehicles must not degrade above
10-6
-------
the standards prescribed for assembly line vehicles. The standards
should therefore extend over the life of the products, as authorized
by the Act. Several compliance strategies can be used to ensure the
maintenance of standards'. The manufacturer is required (by Section
6(d)(D) to warrant for the life of the vehicle that it conformed to stand-
ards at the time of initial sale. Recall is an appropriate remedy
(under Section ll(d)(l)) to require the manufacturer to remedy a class
of vehicles that fails to conform while in actual use, despite proper
maintenance and operation. The tampering with noise emission con-
trol devices and elements of desLgn Is prohibited by Section l!)(a)(2).
Finally, the manufacturer can be required (by Section 6(c)(l)> l<»
provide instructions to purchasers specifying the maintenance, use,
and repair to keep the vehicle within standards.
10-7
-------
SECTION 11
ENVIRONMENTAL EFFECTS
Whenever action is taken to control one form of environmental
pollution, there are possible spinoff effects on other environmental
or natural resource factors. In this section the single effects of
truck noise control on air and water pollution, solid waste disposal,
energy and natural resource consumption, and land use considera-
tions will be evaluated.
It is useful to recall that the principal sources of truck power
train noise are the fan, engine, and exhaust. Fan noise control
involves the use of more efficient, large, slowly turning fans and
fan clutches that disengage the fan entirely when fan cooling of the
engine is not required. Engine noise reduction is achieved by means
of damped and vibration-isolated engine components and enclosures.
Exhaust noise is principally controlled through the use of more
effective mufflers.
AIR
The major potential effect on air pollution from the noise con-
trol measures described above would be an increase in engine exhaust
emissions as a result of an increase in exhaust system back pres-
sure (Reference 1). Truck exhaust mufflers have been designed
and tested that adequately reduce exhaust noise without exceeding
engine manufacturers back pressure specifications. Accordingly,
no increase in air pollution is to be expected from noise control
11-1
-------
related to exhaust mufflers. Air intake systems modifications, should
they be necessary, are not expected to result in any change in vehicle
performance or increase air emissions.
WATER AND SOLID WASTE
There are no significant impacts that would apparently result from
truck noise control on either water quality or solid waste
disposal.
ENERGY AND NATURAL RESOURCE CONSUMPTION
There are several ways in which noise control may affect energy
consumption. The major factor is the use of fans that can be dis-
engaged when not required. Fax (Reference 2) develops the following
estimates of fuel savings in gallons per mile per unit of accessory
horsepower not used.
Truck Category
Medium Heavy
Engine Type Duty Duty
Gasoline .0035 .0019
Diesel .0019 .0010
Also, the following annual mileages by truck category apply:*
Truck Category
Medium Heavy
Engine Type Duty Duty
Gasoline 10,000 18,000
Diesel 21,000 54,000
* Data reduced from U.S. Bureau of Census, 1973.
11-2
-------
Finally, the following number of trucks were in use in 1972 (see
Sections 3 and 8).
Truck Category
Medium Heavy
Engine Type Duty Duty
Gasoline 2,335,000 509,000
Diesel 41,000 648,000
Combining the data in the above three tables, as well as the
estimated savings of 6 hp for gasoline trucks and 15 hp for gaso-
line trucks and 15 hp for diesel trucks, shows that if all trucks were
equipped with large thermostatically controlled fans, approximately
one billion gallons of fuel would have been saved in 1972, more than
that actually consumed.
A secondary energy effect might involve decreases in engine ef-
ficiency as a result of increased exhaust system back pressure.
Since exhaust systems can generally be made to meet engine manu-
facturers back pressure specifications, any effect on fuel consump-
tion in this area is expected to be minor. Further, there is no
empirical evidence that acoustically effective mufflers necessarily
create high back pressure.
Another potential secondary effect on fuel consumption is the
increased truck rolling resistance attributable to the weight of noise
control materials. The weight of noise-reducing materials varies
from a few pounds for a thermostatic fan clutch or compliant engine
mounts to potentially several hundred pounds for an engine
enclosure. Even several hundred pounds, however, represents only a
11-3
-------
fraction of one percent of the total vehicle weight of medium and heavy
trucks. Since only a small fraction of the energy generated by a truck
engine is used to overcome rolling resistance (most is used to over-
come aerodynamic drag), the effect of additional weight on energy
and hence on fuel consumption is considered inconsequential.
Effects on the consumption of other natural resources are expected
to ho small. As indicated, no more than the addition of several
hundred pounds per truck are likely to be required for noise treatment,
under models 2 and 3 used earlier in this document. This is a small
fraction of the roughly 25,000 to 30,000 Ibs per tractor/trailer
vehicle.
LAND USE
The expected effect of a Federal new truck regulation on land use
could conceivably be favorable. For example, land bordering on
highways and streets could become more desirable for residential
and commercial use as the environmental noise from medium and
heavy trucks is reduced. However, should the foregoing not be the
case, it can certainly be stated that Federal regulations would not
adversely affect land use.
11-4
-------
REFERENCES FOR SECTION 11
1. Bender and Patterson, "The Technology and Costs of Quieting
Medium and Heavy Trucks, " BBN Report 2710, 1974.
2. Fax, G. E., "Costs of Operating Quiet Trucks, " BBN Tech Memo
190, 1974.
11-5
-------
APIM2NDK A: DRRIVATION OK HASIC SITHATIOINTA1, MODKL EQUATIONS
In Section 6, Tables 6-6 and 6-7 presented the calculated truck
noise levels (in dB(A) measured at 50 ft from the truck), which, if
permitted, would raise the sound level at a particular site 10 dB(A)
above the appropriate ambient level assumed to have existed prior
to the passage of the truck. These calculations are based on the
standard acoustic concepts presented below.
A truck is regarded as a random isotropic acoustic source whose
acoustic power output is characterized by a spectral density W(4) in
.watts per hertz at frequency -f . It is also assumed that this acoustic
power is radiated into a half space. These as sum pt ions imply that
X-(-f), the intensity spectral density of the source, is the panic on
the surface of any hemisphere in the half space which has the source
at its center. It is given by
,
(Watts ?cr cm* per Hz.) (A.l)
STT/I
where f\ is the distance in cm from the source to a field point
of interest. For the purposes of this analysis it will lie assumed that
the activity site structure, upon which tin-truck noise impinges
is at some .single representative distance from the source. This
distance is the/t in Equation (A.I).
A-l
-------
Now let the surface area of the structure of interest be composed
of /T\ different types of partitions (i.e., walls, windows, etc.) and
let the C type have an area At and a transmission coefficient *C;(4).
Also let I^$) be the intensity spectral density transmitted through
the i "* type surface. Then the total power spectral density
transmitted into the structure is
»
= £
m
*. •» i f t
(A.
Here,
(A. 3)
Thus,
wrcn =
«-M
(A. 4)
The transmittance T ff ) for the composite surface is defined by
TCW= E AttiW. (A. 5)
I
By Equations (A. 4) and (A. 5).
(A>6)
A-2
-------
It is noted that transmission coefficients are not custom-
arily reported directly in the literature. Transmission loss
is usually given in decibels. The quantities "tT^Cf) and
are related as follows:
= IQ tW) (A. 7)
Thus,
- 10 J . (A.8)
The acoustic energy^ produced by the truck with acoustic
power density Vf(f),which has been transmitted from the outside
environment to the activity site interior can now be estimated
For thiSjthe well-known architectural acoustics formula
S — J.—i.. - mean intensity spectral density (A. 9)
Aw
(watts per cm* per Hz)
inside the room
is employed, where A\t) is the total number of absorption units inside
*i« A / f\
the room in cm . /\\r/is customarily given in square feet and is
then called Sabins. Absorption units in cm are more convenient in the
present instance.
A-3
-------
The absorption A.VT) ratl be computed as follows. Let the interior
of the room be bounded by fsj different types of surfaces (i.e., plaster
wall, carpets, etc. ) and let each type surface have an area » in •-.ni
J
and an absorption coefficient 0dj . In addition, let the room contain
P^l objects each contributing \jy$ absorption units. Then the total
number of absorption units in the room is
Values of ot'Ajff and v/uVTy are tabulated for many surfaces and objects
j •*
and are readily available in the literature.
Combining Equations (A. 6) and (A. 9), on£ of the basic formulas
of this analysis is obtained:
TU) 'wtf).
-------
Now, in this project report, the quantity used for intensity is the
A- weighted intensity. This means that each component IH^T) is
weighted by a factor Av'f) • Values of Atfj can be obtained in various
places such as Reference 1.
The curve A in Figure 2. 3 of Reference 1 plots
VI.
where
Thus i
» 10
(A. 13)
to
(A .14)
A few typical values of A\r) are as shown in Table A~l
TABLE A -1 TYPICAL VALUES OP
50
100
200
500
1000
5000
.0008
.0100
.0790
.5000
1.0000
1.0000
The formula for A-weighted intensity which corresponds to Equation
(A. 12) is
rft _
(A. 15)
A-5
-------
By Equations (A. 11) and (A. 15):
(A. 16)
Equation (A. 16) applies to any frequency band where -f 4"f ^T»'
However, most measurement data are available in octave bands and so
some simplifications are made in Equation (A. 16) in order to use the
octave band data. First the most commonly employed octavo bands
are defined in Table A-2.
TABLE A-2
OCTAVE BANDS AND SYMBOLS
Octave
Band
No.
P
1
2
3
4
5
6
7
8
9
Octave Band
Intensity
Jp
(Watts /cm )
J
J
J
J
J
J
J
J
J
Octave
Band
Center
Freq.
fc
(Hz)
31.5
63
125
250
500
1,000
2,000
4,000
8,000
Octave
Band*
Lower
Preq.
(Hz)
22.3
44.6
88.4
176.8
353.6
707.1
1,414.2
2,828.4
5, 656.9
Octave
Band
Upper
Freq.
fu
(Hz)
44.6
89.2
176.8
353.6
707. 1
1,414.2
2,828.4
5,656.9
11.313.7
A-6
-------
In Table A.2,
{A *H
c = Center frequency of *f .octave band >
f • i^V\
T^ = Lower frequency of •£ octave band j
r i Hi
TV* = Upper frequency of -p octave band.
Sorr,e relations between octave band frequencies are:
•+.— «C = Band width of «k**toctave
^ " '-(A. 17)
For convenience, the following notation is adopted:
J \'C^'Ul) S Xb 3 A-weighted intensity in octave band. (A
By Equations (A- 16) and (A- 18),
(A. 19)
In order to make use of available data for the evaluation of tho
integral of Equation (A. 19), inside the -V^orlave band it is
i
assumed that the quantities"^ (fl T(f) and W(-f) are all constant
A-7
-------
and have values corresponding to f^ . the center frequency of llio
octave band . That is. Alf) • Ttf) and W(-f) an? replaced in the
integrand of Equation (A-19) by the constants A(.fj, TC-fJ and W{|-J.
Further, denoting these quantities by Ay T|> and ^L than Equation
(A. 19) becomes
1,2, ..,9. (A. 20)
where f
fob ~ 1 ^**'«»»., (A.21)
• « V •
The quantity/J. may be estimated in various ways, but since it
does not appear in later formulas, it will not be considered further.
Equation (A. 20) gives the octave band intensity (Jjk inside a
room in terms of the acoustic power spectral density of the source
Vrfp. Ordinarily^ the ' Wfe is not known. Thus, this quantity is replaced
by a quantity which is known and measured, namely the dB(A) level
produced in a pass-by test at a prescribed distance. The distance
is usually 50 feet but here it is allowed to be arbitrary ^o in cm.
Using Equation (A. 1) and integrating Equation (A.15) gives
If the same approximations are made in Equation (A. 22) as were
made in Equation (A. 20)^then Equation (A. 22) becomes
A-8V
-------
(A. 23)
Using Equation (A.23)/^A& can be eliminated from Equation (A. 20).
1 Thus, Equation (A.20) becomes
Equation (A .24) gives a simple relation between the A -weighted
octave band levels inside the room and those at the standard lost
distance /(o .
At this point, it is useful to introduce a normalized spectrum for
xj
the source. Define the normalizied A -weighted "\> octave band
A
component as
Now.spectra having the same shape as J^.the one actually meas-
ured .but having different intensities can be generated by simply
^
multiplying all J^k by the same constant -^ . Thus, for a typical
*
case.one can dete rmine ^and raise or lower the total power, keeping
the spectrum shape the same. This was done here us ing two spectra,
one for low speed high acceleration truck operation and the other
for high constant speed truck operation. These spectra are shown
m Figures E.I and E. 2, respectively, of Appendix E.
A-9
-------
In Equation (A, 24^ Jokis replaced by
o
become '
(A.l'(i)
The total intensity inside the' room, summed over all the octave
bands, is defined as J^. and is given by
(A; 27)
For convenience, define the parameter QL as
QL
and, thus
(A. 29)
c
The intensity at the reference distance J\^ is /^ J^summed over
T'1
(A. 30)
The overall dB(A) level of the source at £o is
and the ;dB(A) level inside the room
at. A is
A-10
-------
By Equations (A. 29). (A. 31) and (A. 32). then
+ 10 Jo. (£?• . (A.
Equation (A ..33) gives the overall dB (A) level $o of a trucl^hav-
ing a proscribed spectrum and measured at distance /lo . which
will produce a dB(A) level fyj *n a room which is at a distance f{
and has specified absorption -an* transmission loss. For the
calculations in this project report, £^ was taken as 10 dB(A)
above. the ambient for the given scenario.
A-U
-------
APPENDIX B: ARCHITECTURAL-ACOUSTIC DESCRIPTION OF THE
ACTIVITY SITE STRUCTURES
Two fundamental considerations enter into the architectural -
acoustic description of the structure at a particular activity site. These
considerations involve (1) the loss of acoustic energy on sound passage
through the partition of a structure and (2) the absorption of sound
by the surfaces within the activity space of the structure.
To account for the phenomena associated with these considerations,
each activity site was defined in terms of physical geometry, structural
material, and interior furnishings. Tables B-l, B-2 and B-3 provide
architectural-acoustic data for the apartment room, frame house room,
and office room, respectively, considered in this study.
B-l
-------
Site Component
Exterior Wall
Window
Interior Walls &
Ceiling
Floor
Draperies
People
TABLE B.I
DESCRIPTION OF APARTMENT ROOM
Description
90 ft transmission area.
Construction: brick, laid on edge with
gypsum plaster on both sides.
Transmission loss: see Reference 1, page 434.
30 ft transmission area.
Construction: single 1/8 inch thick pane
with 1. 626 Ibs/ft surface density.
Transmission loss: see Reference 2, page 109.
740-ft surface area.
Construction: plaster, gypsum, scratch
and brown coats on metal lath on wood studs.
Absorption: see reference 1, page 425.
30Q-ft surface area.
Construction: pile carpet on 1/8 inch felt.
Absorption: see Reference 1, page 424.
120-ft surface area.
Construction: 18 oz. /yd velours.
Absorption: see Reference 1, page 424.
Four adults seated in American loge chairs.
Absorption: see Reference 1, page 426.
B-2
-------
TABLE B. 2
DESCRIPTION OF FRAME HOUSE ROOM
Site Component
Exterior Wall
Windows
Interior Walls
Ceiling
Floor
Chairs
People
Description
280-ft transmission area.
Construction: 1/2 inch thick lime plaster-
on wood lath.
Transmission loss: see Reference 1, page 428.
70-ft transmission area.
Construction: single 1/8 inch-thick pane
with 1, 626 Ibs/ft surface density.
Transmission loss: see Reference 2, page 109.
500-ft surface area.
Construction: plaster, gypsum, scratch and
brown coats on metal lath on wood studs.
Absorption: see Reference 1, page 425.
300-ft surface area.
Construction: 1-inch thick type M-2 acoustic
Celotex 12-inch x 12-inch tiles.
Absorption: see Reference 1, page 409.
300-ft surface area.
Construction: linoleum on concrete.
Absorption: see Reference 1, page 424.
Two tablet arm chairs with seats down,
upholstered with Durano plastic seat
covering and mohair side vents.
Absorption: see Reference 1, page 426.
Two adults.
Absorption: see Reference 1, page 426.
B-3
-------
TABLE B.3
DESCRIPTION OF OFFICE ROOM
Site Component
Exterior Wall
Windows
Interior Walls
Ceiling
Floor
Chairs
People
Description
60-ft transmission area.
Construction: brick, laid on edge with gypsum
plaster on both sides.
Transmission loss: see Reference 1, page 434.
60-ft surface area.
Construction: single 1/8 inch-thick pane
with 1,626 Ibs/ft surface density.
Transmission loss: see Reference 2, page 109.
500-ft surface area.
Construction: plaster, gypsum, scratch and
brown coats on metal lath on wood studs.
Absorption: see Reference 1, page 425.
300-ft surface area.
Construction: 1-inch thick type M-2 acoustic
Celotex 12-inch x 12-inch tiles.
Absorption: see Reference 1, page 409.
300-ft surface area.
Construction: linoleum on concrete.
Absorption: see Reference 1, page 424.
Two tablet arm chairs with seats down,
upholstered with Durano plastic seat
covering and mohair side vents.
Absorption: see Reference 1, page 426.
Two adults.
Absorption: see Reference 1, page 426.
B-4
-------
REFERENCES FOR APPENDIX B
1. Knudson, V. O. and C. M. Harris, Acoustical Designing in
Architecture, John Wiley & Sons, Inc., 1950.
2. Richardson, E. E., Technical Aspects of Sound. Vol. I, Elsener
Publishing Co., 1953.
B-5
-------
APPENDIX C: CALCULATION OF THE TOTAL ABSORPTION FOR
THE APARTMENT ACTIVITY SITE
The total absorption of each activity space for the environmental
activity sites was calculated by summing the number of absorption
units associated with major sound absorbing surfaces within the ac-
tivity space of the site of interest. Here, an absorption unit is defined
as the product coefficient of a surface and the related surface area.
Table C. 1 summarizes the steps taken to obtain the total absorp-
tion for the apartment environmental activity site.
Table C. 2 provides some comments on the column data in Table
C.I
TABLE C. 2 COMMENTS ON TABLE C. 1
Column Comments
1 Octave band center frequencies, Hz.
2, 3,4 = absorption coefficient (see Appendix B).
A = surface area, cm .
A = Absorption, Absorption Units.
5 Absorption for four persons, absorption units
(see Appendix B).
6 These values are the sum of (1) the A data
of columns 2 through 4 and (2) the data of
column 5, absorption units.
C-l
-------
TABLE C-l
ABSORBENCY OF THE APARTMENT•INTERIOR
1
Octave Band
Center
Frequency
Hz
125
250
500
1000
2000
4000
COLUMN NUMBERS
. i
2
Carpeting
A = 27R,700 cm2
a aA
.11 30,700
.14 39,000
.37 103,100
.43 119,800
.27 75,300
.25 69,700 '
3
Walls and
Ceiling
A = 687,500 cm2
u aA
.02 13,800
.03 20,600
.04 27,500
.06 41,300
.06 41,300
.03 20,600
4
Drapes
A = 111,500 cm2
ct aA
.05 5,600
.12 13,400 •
.35 39,000
.45 50,200
.38 42,400
.36 40,100
5
People
11,200
14,100
16,700
18,600
19,300
20,300
6
Octave Band
Total
Absorption
1
61,100
87,200
185,400
i
229,800
178,200
150,500
I
-------
APPENDIX D: CALCULATION OF THE TOTAL TRANSMITTANCE
OF THE APARTMENT ACTIVITY SITE
The total transmittance for the structure associated with each
environmental activity site was calculated by summing the transmit-
tance associated with major sound transmitting partitions for each
particular structure. Here, transmittance is defined as the product
of the transmission coefficient of a partition and the related surface
area.
Table D. 1 summarizes the steps taken to obtain the total trans-
mittance for the apartment activity site. Table D. 2 provides some
comments on the column data in Table D. 1.
TABLE D-2 COMMENTS ON TABLE D-l
Column Comments
1 Octave band center frequencies, Hz.
2, 3 = transmission coefficient (see Appendix B)
A = surface area, cm
= transmittance, transmission units.
4 These values are the sum of the data of columns
2 and 3.
D-l
-------
TABLE D-l.
TRANSKLTTANCE OF THE APARTMENT STRUCTURE
D
to
Column Numbers
1
Octave Band
Center
Frequency
•Hz
125
250
500
1000
2000
4000
2
Windows
A = 2.787 X 104 c~^
T. t:A
17.430 X 10"3 435.3
4.416 X 10~3 123.1
1.108 X 10~3 30.9
.277 X 10"3 7.7
.069 X 10" 3 1.9
.017 X 10"3 0.5 -
3
Walls
A = 8.361 X 10^ en;2
t TA
12.589 X 10~4 105.3
1.000 X 10~4 8.4
2.000 X 10"4 16.8
.126 X 10~4 1.1
.013 X 10~4 .1
.006 X 10~4 0
h
Octave Band
Total
Trans mi ttance
591.1
131.5
47.7
8.8
2.0
.5
-------
APPENDIX E: TYPICAL MEASURED TRUCK OPERATION NOISE
Noise spectrum associated with the two most common truck
operations were selected for study. These were (1) low speed, high
acceleration truck operation and (2) constant high speed truck operation.
Review of available literature led to the selection of the overall noise
levels and spectrum for the particular truck operations below.
Truck Noise at Low-Speed, High-Acceleration Operation
Low speed high acceleration truck operation usually occurs when a
truck at standstill begins movement. This condition has been recognized
as one producing relatively high levels of noise. The data shown in Figure
E-l are considered typical and representative of noise associated with
the subject truck operating condition (Reference 1).
Truck Noise at Constant High Speed Operation
Constant high speed truck acceleration usually occurs when a truck
is operating on a freeway. Noise levels generated during this mode of
operation have also received considerable attention. The data shown
in Figure E-2 are considered typical and representative of noise gener-
ated during constant high-speed truck operation (Reference 2).
E-l
-------
110
100
9
«
2
£
£
•g
I
90
80
70
60
50
40
O Total
I
OA 63 125 250 500 1000 2000
Octave Band Center Frequencies, Hz
4000
8000
Test Site and Procedure Similar to SAE J366b Specifications.
Figure E-l Typical Measured Low-Speed, High-Acceleration Truck Operation
Noise
e-z
-------
110
100
90
Total
80
70
60
50
40
OA
63
_L
J.
J.
J.
125
250 500 1000 2000 4000 8000
Octave Band Center Frequencies, Hz
Noite Measured at 50 Feet From Centerline of Road
Figure E-2 Typical feasured Constant High-Speed Truck Operation Noise,
E-3
-------
REFERENCES FOR APPENDIX E
1. Wyle Laboratories Communication R/59161 with EPA, Table 2
(SAE J366 data), January 1974.
2. "Truck Noise III-A: Preliminary Noise Diagnosis of Freightliner
Datum Truck-Tractor, " Department of Transportation Report
DOT-TST-73-6, May 1973.
E-4
-------
APPENDIX F: CALCULATIONS TO NORMALIZE THE LOW SPEIOD
HIGH-ACCELERATION TRUCK NOISE SPECTRUM
To facilitate their usage in the procedure developed to obtain
the truck noise levels at BO feet that might preclude annoyance,
the truck noise spectra of Figures E-l and E-2 were normalized
to a total sound intensity of one watt /cm .
Table F-l summarizes the steps taken in this normalization
process for the noise spectrum associated with the low speed, high
acceleration truck operation. Table P- 2 provides some comments
on the column data in Table F-l.
TABLE F. 2
COMMENTS ON TABLE F. 1
Column Comments
1 Octave band center frequencies, Hz
2 Sound level data from Figure E-l
3 Column 2 data converted to sound intensities
4 Individual column 5 data divided by the sum
of the column 5 values.
F-l
-------
I
NJ
TABLE F-l
NORMALIZATION OF THE LOW-SPEED, HIGH-ACCELERATION TRUCK NOISE SPECTRUM
Column Numbers
1
Octave Band
Center
Frequency
Hz
12
500
;ooo
2000
4000
f
2
Octave Band.
Sound Lavol
72
78
j
82
Ol'
77
; 73
3
Octave Band
Souhd Intensity
Watts /cm1
1.58* 10-9
6 . 31 x 1C-9
15.84X 10-9
12.59X 10-9
5.01xio-9
2.00X io~9
4
; Normalized
Octave Band
Sound Intenui.ty
,036
.146
.366
.290
.116
.046
-------
APPENDIX G: CALCULATION OK ACTIVITY SITE FACTORS KOIt
THE APARTMENT ACTIVITY SITE
The activity site factor, q for the pth octave hand, i*
defined as A
Jo (G.I)
q = Tp Jop
where A and Tp are the pth octave band absorption and trans-
mission loss for the particular activity site structure of interest
and Jop is the normalized A -weighted sound intensity of the truck
noise for the p octave band. These activity site factors summed
over all octave bands of interest to give the parameter q . See
Equation (A. 28) of Appendix A.
Table G. 1 summarizes the steps taken to obtain the activity
site factors for the apartment activity site. Table G. 2 provides some
comments on the column data in Table G. 1.
TABLE G. 2 COMMENTS ON TABLE G. 1
COLUMN COMMENTS
1 Octave Band Center Frequencies
2 Data from Column 6 of Table C.I,
Absorption Units
3 Data from Column 4 of Table D. 1,
Transmission Units
4 Data from Column 4 of Table F. 1
5 These values are the product of the data of
Columns 3 and 4 divided by the data of
Column 2 (see Equation (G.I)
G-l
-------
TABLE G-l
CALCULATION OF SITUATIONAL FACTORS FOR THE APARTMENT ACTIVITY SITE
i
to-
1
Octave Band
Cjenter
Frequency
Hz
125
250
500
1000
2000
4000
— — — — — —
2
Octave Band
Absorption
A*
61,000
87,200
186,400
229,800
178,200
150,500.
Co ; umn Numbers
3
Octave Band
. Transrnittance
T>
591.1
131.5
47.7
8.8
2.0
.5
4
.Octave Band
Normalized
Truck^Joise
Joj>
.036
.146
.366
.290
.116
.046
5 .
Octave Band
Situational
Factor
«3U
ffP .
3488 X 10"7
2202 x 10"7
937 X.10~7
111 X 10~7
.13 X 10~7
2 X 10 ~7
-------
APPENDIX H: PROCEDURE USED TO OBTAIN THE TRUCK NOISE LEVELS
AT 50 FEET THAT MIGHT PRECLUDE ANNOYANCE
The following steps were taken to obtain the desired truck noise levels:
Step 1: Depending on the human activity and activity site (e. g.,
a thought process in an apartment), the acceptable ambient
noise level was increased by 10 dB(A) to represent the level
of the extraneous intrusive noise likely to provoke a strong
feeling of annoyance.
Step 2: Using the appropriate absorption data for the activity spaces
(e.g., an apartment interior), the total absorption units
for each activity site were calculated.
Step 3: Using the appropriate transmission loss data for the activity
site (e. g,, an apartment building), the transmittance of the
structure separating the activity space from the truck
noise was calculated.
Step 4: Using the appropriate truck noise spectrum, a normalized
noise spectrum was calculated to facilitate the analysis.
Step 5: Using the data generated in Steps 1 through 4 above, truck
noise levels at 50 feet that might preclude annoyance were
calculated for different human activities in various activity
spaces at particular activity sites.
H-l
-------
APPENDIX I DETAILED INITIAL COST ESTIMATES TO QUIET
MEDIUM AND HEAVY DUTY TRUCKS
The noise control treatments considered in this analysis are listed
in Table 1-1. Table 1-2 shows which treatments apply to a given
vehicle as a function of noise level, and the truck retail price increase
associated with the treatments.
1-1
-------
TABLE I.I NOISE CONTROL KEY
System
Fan
H
I
Cab
Code
Description of Noise Control Measure
al Use of larger slower turning fan
with shrouding
a2 Larger slower turning fan with
thermostat control to eliminate
shutters or control their opening
a3 Best technology fan system
Exhaust bl Best available system
b2 Advanced system better th=r. pres-
e ntly available
b3 Best technology exhaust system
Engine cl Close fitting covers arid isolated
or damped exterior parts supplied
by engine manufacturer
dl Underhood treatment such as acous-
tic absorbing material, side
d2 Partial or full engine enclosures
Source Level or
Noise Reduction
80
75
65
75
75
65
2 - 3
Noise Reduction
10 - 15
Noise Reduction
-------
TABLE 1.2 ESTIMATED CUSTOMER PRICE INCREASES FOR QUIETED TRUCKS
Engine Class'-*-
X.D. Gasoline
Engines
H.D. Diesel Engines
X»r.ufacturer A
H.D. Dles-1 Engines
Manufacturer E
H.D. Diesel Engines
rvar.ufacturer B
H.D. Diesel Engines
Manufacturer C
tf.D. Diesel Engines
Manufacturer D
H.D. Diesel Engines
Manufacturer D
H.D. Diesel Engines
Xar.ufactur-r A
K.D. Dles-1 Engines
Manufacturer E
•i.D. Diesel Engines
Manufacturer C
i.i>. Diesel Engines
Xi-iufacturer F
".D. Diesel Engines
Manufacturer G
H.D. Diesel Engines
Manufacturer H
M«rket>
Share ^
65*
12*
6*
6*
1.8*
2.2*
1.5*
0.9*
0.77*
0.47*
0.225J
0.17*
0.015*
Model 1, 83 dB(A)
Fan
t
al
$100
a2
$100
a2
$100
a2
—
$100
a2
al
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
—
Exhaust
-
$ 50
bl
$ 50
bl
$ 25
bl
—
$ 25
bl
-
$100
b2
—
-
$ 25
bl
$ 25
bl
—
Engine
-
—
$275
cl
$200
cl
-
-
-
-
-
-
-
-
—
Cab
-
—
—
—
—
-
-
-
-
-
-
-
—
Total
$150
$425
$325
$0
$125
$200
$100
$100
$125
$125
$0
Model 2, 80 dB(A)
Fan
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
$100
a2
Exhaust
$ 25
bl
$ 50
bl
$ 50
bl
$ 25
bl
$ 25
bl
$ 25
1 1 .;)
$ 50
bl
$100
b2
$ 25
bl
$ 25
bl
$ 25
bl
$ 25
bl
* 25
bl
Engln
-
$200
cl
-
-
—
$ 85
cl
-
$200
cl
$175
cl
$175
cl
$200
cl
$150
cl
—
Cab
-
•
$850
d2
$675
d2
-
$100
dl
-
-
-
-
-
-
—
Total
» 125
* 350
$1000
$ 800
$ 125
$ 210
$ 150
$ 'too
$ 300
$ 400
$ 325
$ 275
$ 125
Model 3, 75 dB(A)
Fin
$150
a3
$150
a3
$150
83
$150
a3
$150
a3
$150
a3
$150
a3
$150
a3
$150
a3
$150
a3
$150
a3
$150
a3
$150
a3
EnhiuJt
$ 50
b2
$100
b2
$100
62
$ 75
b2
$ 75
b2
$ 75
b2
$1CO
62
$150
62
$ 75
62
$ 75
62
$ 75
62
$ 75
bZ
$ 75
62
Engine
-
-
-
-
$200
cl
-
-
-
-
-
-
-
$200
cl
C«t>
$100
dl
Total
$3CO
ifjo- 1 *:;:;-
1250 [ :;.:
1253
$775
d2
dl
S775-
1275
S1I33
$5:5
1250
d2
' — ;;-j- '
a;
JT75-
1275
*775-
1275
4775-
1275
4T 1
1275 j
$100
dl
15C3
*":iir
15:3
15:3
13:0
i •"::
$525
JM.D. • nedlun duty, H.D. • heavy duty. M.D. and H.D. refer to severity of service.
of a noisy engine by a quiet engine Is possible within N.D. and H.D. classes.
Exchange:
^Percent of medium and heavy duty trucks powered by indicated engine family, 1972.
-------
APPENDIX J: COSTS OF OPUUATINC, QtUKT TRUCKS
As was described in Section 7, "Changes in Operating Costs, " the
effects of adding noise control devices to trucks are (1) to change the
cost of their operation and (2) to change their operating capabilities.
This second effect, in turn, can he quantified in terms of the extra cap-
ital cost necessary to maintain the truck's previous level of Hervlre.
This appendix contains the detailed calculation of these cost changes.
Tables J-l and J-2 show the effect of changes in vehicle character-
istics on fuel consumption per mile and the gross engine power needed
to maintain truck performance. The development of theme I'igureH in
based on the references at the end of Section 7.
TABLE J.I EFFECT OF CHANGES IN VEHICLE'CHARACTERISTICS
ON FUEL CONSUMPTION
Gasoline
Gasoline
Diesel -
Diesel -
- medium
- heavy
medium
heavy
Effect of Change in
GVWR
(gpm/lb)
3.25 x 10~6
3.25 x 10~6
1.77 * ID'6
1.77 x 10~6
Bkck pressure
(gpm/in. Hg)
0
0
.00050
.00021
Accessory Horse-
power (gpm/hp)
.0035
.0019
.0019
.0010
Source: Reference No. 1.
J-l
-------
TABLE J 2 EFFECT pF CHANGES IN VEHICLE CHARACTERISTICS ON
GROSS ENGINE POWER NEEDED TO MAINTAIN A GIVEN TOP SPEED
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Effect of Change 1n
GVWR
(hp/lb)
.0020
.0020
.0020
.0020
Back pressure
(hp/in. Hg)
1.1
2.1
2.0
3.0
Accessory Horse-
power (hp/hp)
1
1
1
1
The fuel consumption sensitivities in Table J-l can be converted
into cost coefficients by multiplying gallons per mile by the annual mile-
age and the average price of fuel per gallon. Values for these quantities
are given in Table J~3. The corresponding annual costs are shown in
Table J -4.
TABLE J-3 ANNUAL MILEAGE AND FUEL PRICES BY TYPE OF TRUCK
'
Gasoline
Gasoline
Diesel -
Diesel -
- medium
- heavy
medium
heavy
Annual Mileage1
(103 mi/yr)
10
18
21
54
Fuel Price2
($/gal)
.50
.50
.30
.30
1 Source; Data reduced from U.S. Bureau of Census
(tape), 1973.
2Estimate based on Oil and Gas Journalt March 11,
1974.
J-2
-------
TABLE J-4
ANNUAL OPERATING COST INCREASES AS A RESULT OF
CHANGES IN GVWR, BACKPRESSURE, AND ACCESSORY HORSEPOWER
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Annual Operating Cost Increase Per Unit
GVWR
($/lb)
.016
.029
.011
.029
Back pressure
($/1n. Hz)
0
0
3.15
3.40
Accessory Horse-
power ($/hp)
17.50
17.10
11.97
16.20
The cost of the incremental horsepower requirements shown in Table
J-2 can be computed by multiplying the horsepower figures by the cost
per unit horsepower. Manufacturers' data reported in reference 1, indi-
cate that the average price per horsepower for medium and heavy duty
diesel engines is $16 and $24, respectively. Assuming that gasoline
engines cost 60% of their diesel equivalents, the corresponding unit
prices for gasoline horsepower are approximately $10 and $14. Multiply-
ing these unit costs by the figures in Table J-2 gives the indirect capital
cost per unit change in vehicle characteristics, as shown in Table J-5.
J-3
-------
TABLE J.5. INDIRECT INCREASE IN CAPITAL COST AS A Itl.SUU 01
CHANGES IN GVW, BACKPRESSURE, AND ACCESSORY HORSU'UWUl
Gasoline - medium
Oasoline - heavy
Diesel - medium
Diesel - heavy
1 Capital Cost Incrouso Per Unit
GVWR
($/lb)
.0?0
.028
.032
.0*18
Hackpressurc
($/1n. II rj)
I'l.O
29.4
3^.0
7?.0
Accessory Horr.u-
pownr ($/lij>)
10
J'« *
1C
?l\
To obtain the actual costs associated with the various noise levels,
modeled, we must multiply the cost coefficients of Tables J-4 and J-5
by the changes in truck characteristics which would be induced by the
necessary noise control measures. These changes are shown in Table
J-6 for the noise control treatments listed in Table 1-1 of Appendix
I. The total cost increase (operating or indirect capital) for a particular
level and truck category is thus obtained by finding the changes
in truck characteristics for those treatments (Table J-6), multiplying
these by the operating or, indirect capital cost coefficients (Tables J-4
and J-5) as appropriate, and summing the results over all treatments
for that truck category and level. When this is done for
operating costs, the results shown in Table J-7 are obtained.
J-4
-------
TABLE J-6
CHANGES IN TRUCK OPERATING CHARACTERISTICS FOR
NOISE CONTROL TREATMENTS1
vn
Code
al
a2
a3
bl
b2
b3
cl
dl
d2
Treatment
Large Fan
Large Fan with
Thermostat Control
Best Tech. Fan
System
Best Available
Muffler
Advanced Muffler
High Tech. Muffler
Covers
Underhood Treat-
ment
Enclosure
AGVW (lb)
Med Hvy
0 0
100 200
100 200
0 0
0 0
250 500
A Back pressure
(in. H20)
Med Hvy
0 0
0 0
15 15
Ahp
Med Hvy
(3) (7)
(6) (15)
(6) (15)
^Maintenance
Cost ($/yr).
Med Hvy
~
$ 9* $ 19*
$ 19" $ 38*
$ 38" $ 76*
$1502 $300*
1 Source.: Estimates by noise control engineers based on past truck-quieting
experience •
Represents 10 man-hours per year at a burdened labor rate of $15/man-hour.
Represents 20 man-hours per year at a burdened labor rate of $15/man-hour.
''Includes incremental cost of replacing muffler three times in 8 years.
-------
TABLE J.7. CHANGES IN ANNUAL COST (FUEL PLUS MAINTENANCE
EXPENSES) CAUSED BY NOISE CONTROL TREATMENTS
(INCLUDES FAN SAVINGS)
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Annual Cost Change1
Modol 1
$ 53)
($1?0)
($ 63)
($224)
Model 2
($ 96)
($238)
($ 63)
($ 66)
Model 3
($ 6>l)
($21.0)
$ \il
$.116
1 Parentheses denote net savings.
The table shows that the changes in operating cost, as computed, are
almost always net savings, due to the reduced power requirement of the
fan. Such savings could be ascribed to other than the noise control effort,
however, because (1) truck operators could use the fan power savings
to increase speed; and (2) market forces could dictate such a beneficial
design modification eventually, even without considererations of noise
reduction. Therefore, the operating costs have been recomputed to
exclude the fan horsepower savings. The results are shown in Table
J. 8.
J-6
-------
TABLE J-8 CHANGES IN ANNUAL COST (FUEL PLUS MAINTENANCE
EXPENSES) CAUSED BY NOISE CONTROL TREATMENTS
(WITHOUT FAN SAVINGS)
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Annual Cost Increase
Model 1
0
0
$ 9
$19
Model 2
$ 9
$ 19
$ 9
$176
Model 3
$ 21
$ M
$123
$359
The cost of extra horsepower needed to maintain the original level
of service is shown in Table J-9. The fan savings result in a smaller
required total engine output, hence a reduction in the initial price. For
the reasons listed in the preceding paragraph, however, these savings
may not be realized. The indirect capital cost increase is therefore
shown in Table J -10 with fan savings excluded. The cost of extra horse-
power required by noise control treatments is negligible.
J-7
-------
TABLE J-9 CHANGES IN CAPITAL COST INDIRECTLY CAUSED UY
NOISE CONTROL TREATMENTS (INCLUDES PAN SAVINGS)
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Capital Cost Change
( ) Denotes Net Savings
Model 1
($ 30)
($ 98)
($ 96)
($360)
Model 2
($ 60)
($210)
($ 96)
($336)
Model 3
($ 58)
($204)
($ 85)
($326)
TABLE J-10 CHANGES IN CAPITAL COST INDIRECTLY CAUSED BY
NOISE CONTROL TREATMENTS (WITHOUT FAN SAVINGS)
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Capital Cost Increase
Model 1
0
0
0
0
Model 2
0
0
0
$12
Model 3
$ 2
$ 6
$11
$35
J-8
-------
APPENDIX K: COMPUTATION OF EQUIVALENT TRUCK PKICH
INCREASES
This apppendix contains the detailed calculations for the results
summarized in Table 7-6 in the test. The equivalent price increase
for a given truck category is obtained by summing the direct price
change (Table 7-1), the indirect price change (Table 7-3a or 7-3b)
and the net present value of the charge in operating cost
(Tabte 7-2a or 7-2b). Net present value is evaluated over 10 years
at 10% interest.
Tables K-l through K-3 show the computation of equivalent price
changes for each of the three models employed in this document.
K-l
-------
TABLE
CALCULATION OF EQUIVALENT PRICE FACTOR -MODEL 1
Type
Without Fan Savings
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
With Fan Savings"
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Direct
Price Change1
$ 0
0
104.16
19^.56
. $100. CO
100.00
120.83
214.65
Indirect
Price Change2
$ 0
0
0
0
($ 30)
( 98)
( 96)
' ( 360)
Present Value
of Change in
Operating Cost3
$ 0
0
55.30
116.74
($ 325.63)
( 737.28)
( 387.07)
( 1,376.26)
Total
$ 0
0
159.46
311.30
($ 255.63)
( 735.28)
( 362.24)
( 1,521.61)
ro
Source:
2Source:
Table 7-1.
Tables 7-3a and 7-3b.
3Source: Tables 7-2a and 7-2b. Net present value computed over 10 years at 10% interest
(PV factor = 6.144).
'""The "with fan savings" case assur.es that all trucks will adopt fan treatments, thereby
incurring both costs and benefits.
-------
TABLE K-2 CALCULATION OF EQUIVALENT PRICE FACTOR - MODEL
Type
Without Fan Savings
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
With Fan Savings
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Direct
Price Change1
$125-00
125.00
264.16
487.62
. $125.00
125.00
264.16
487.62
Indirect
Price Change2
* -
$ 0
0
0
12
($ 60)
( 210)
( 96)
( 336)
Present Value
of Change in
Operating Cost3
$ 55.30
116.74
55.30
1,081.34
($ 589.82)
( 1,462.27)
( 387.07)
( 405.50)
Total
$ 180.30
241.74
319.46
1,580.90
($ 524.82)
( 1,547-27)
( 218.91)
( 253-88)
X
I
UJ
'.Source: Table 7-1.
2Source: Tables 7-4a and 7-4b
^Source: Tables 7-3a and 7-3b
(PV factor = 6.144).
Net present value computed over 10 years at 102 interest
-------
TABLE K-3 CALCULATION OF EQUIVALENT PRICE FACTOR - MODEL 3
Type
Without Fan Savings
Gas - medium
Gas -heavy
Diesel - medium
Diesel _ heavy
With Fan Savings
Gas - medium
Ga.S - heavy
Diesel - medium
Diesel - heavy
Direct
Price Change1
$ 300.00
300.00
1,129.12
"1,119-32
• $ 300.00
300.00
1,129.12
1,119.32
Indirect
Price Change2
$ 2
6
11
35
($58)
(204)
(85)
(326)
Present Value'
of Change in
Operating Cost3
$ 129.02
270.34
755.71
2,205.70
(5516.10)
(1,290.24)
313.34
712.70
I
Total
$ 431.02
576.34
1,895.8^
"3,360.02 |
j
($274.10;
' (1,194.24)
1,357.46
1,506.02
1.
2.
3.
Source: Data from table 7-1; computational procedure from page 7-16
Source: Tables 7-4a and 7~4b.
Source: Tables 7~3a and 7-3b.
interest (pv factor
Net present value ccr.cuted over 10 years at
• 6.144).
-------
APPENDIX L: IMPACT OF QUIETING OPTIONS ON TRUCK VOLT IM13
This appendix presents detailed forecasts of truck volume for- uach
truck category under the three models developed with hypothetical
standards and effective dates. The method of computation is described
in Section 7.
L-l
-------
TABLE L-1 REVISED VOLUME FORECAST (WITHOUT-FAN SAVINGS) GASOLINE - MEDIUM DUTY
f
rvj
Year
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Basel ine
Forecast
203,900
206,800
209,800
212,800
215,700
218,700
221 ,600
224,600
228,500
231 ,500
234,400
237,400
241 ,300
244,300
248,200
251 ,200
255,100
258,100
262,000
265,900
269,900
273,800
276,800
280,700
284,700
Volume Reduction
Model 1
0
0
0
0
0
4,811
4,875
11 ,792
11 ,996
12,154
12,306
12,464
12,668
12,826
13,031
13', 188
13,393
13,550
13,755 ,
13,960
14,170
14,375
14,532
14,737
14,974
Model 2
0
0
4,616
4,682
4,745
11,482
11 ,634
11 ,792
11 ,996
12,154
12,306
12,464
12,668
1 2 , 82 6
13,031
13,188
13,393
13,550
13,755
13,960
14,170
14,375
14,532
14,737
14,974
Model 3
0
0
4,616
4,682
4,745
11,482
11 ,634
11 ,792
11 ,996
P
12,154
12,306
12,464
12,668
12,826
1
13,031
13,138 |
13,393
13,550 ;
13,755 j
13,960
14,170
14,375
14,532 !
14,737
14,947
i
-------
TABLE V-2 REVISED VOLUME FORECAST (WITHOUT FAN SAVINGS) GASOLINE - HEAVY
DUTY
I
UJ
Year
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Basel ine
Forecast
40,400
39,400
38,100
38,400
38,600
38,700
38,800
38,800
38,700
38,600
38,400
38,100
'37,700
37,200
36,600
35,900
35,000
33,900
32,800
31 ,500
32,800
34,200
35,700
37,200
38,800
Volume Reduction
Model 1
0
0
0
0
0
573
574
1,370
1,366
1 ,363
1,356
1 ,345
1,331
1 ,313
1 ,292
1,267
1,236
1,197
1 ,158
1 ,112
1 ,158
1,207 ;
1,260 '
1,313
1,370 j
t
Model 2
0
0
564
568
571
1,366
1,370
1,370
1,366
1 353
1 356
1 345
1 331
1 313
i
1,292
1,267
1,236 j
1,197 !
1,155 |
Model 3
0
0
564
568
571
1,366
1,370
1,370
1 ,366
1 ,363
1,356
1 ,345
1,331
1,313
1,292
1,267
1,236
1,197
1 ,158
. 1J12 ! 1,112
",•53 • 1,158
1,2:7 : 1,207
".25D • 1,260
1,3-3 ' 1,313
",3~: : 1,370
-------
TABLE 1-
REVISED VOLUME FORECAST (WITHOUT- FAN SAVINGS) DIESEL - MEDIUM DUTY
Year
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Basel inp
^UJtv 1 1 1 1 C
Forecast
3,100
3,200
3,200
3,200
3,300
- 3,300
3,400
3,400
3,500
3,500
3,600
3,600
'3,700
3,700
3,800
3,800
3,900
3,900
4,000
4,100
4,100
4,200
4,200
4,300
4,300
Volume Reduction
Model 1
0
49
49
49
51
102
105
623
641
641
659
659
677
677
696
696
714
714
732
751
751
769
769
787
787
Model 2
0
49
49
49
51
102
105
623
641
641
659
659
677
677
696
696
714
714
732
751
751
769
769
787
787
Model 3
0
49
99
99
102
604
623
623
641
641
659
659
677
677
696
696
714
- 714
732
751
751
769
769
787
787
-------
TABLE L~4 REVISED VOLUME FORECAST (WITHOUT-FAN SAVINGS) DIESEL - HEAVY DUTY
tr1
i
Year
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Basel ine
Forecast
164,600
173,600
184,900
194,600
204,400
214,300
225,200
236,200
248,300
260,400
273,600
287,900
302,300
316,800
333,400
350,100
367,000
385,100
404,200
424,500
443,200
461 ,800
481 ,300
501 ,800
523,200
Volume Reduction
Model 1
0
1 ,493
1 ,590
1,674
8,973
9,408
9,886
22,037
23,166
24,295
25,527
26,861
28,205
29,557
31 ,106
32',664
34,241
35,930
37,712 .
39,606
41 ,351
43,086
44,905
46,818
48,815
Model 2
0
1,493
1,590
1,674
8,973
9,408
9,886
22,037
23,166
24,295
25,527
26,861
28,205
29,557
31 ,106
32,664
34,241
35,930
37,712
39,606
41 ,351
43,086
44,905
46 ,818
48,815
Model 3
0
1 ,493
8,117
8,543
8,973
19,994
21 ,011
22,037
23,166
24,295
25,527
26,861
28,205
29,557
31,106
32,664
34,241
35,930
37,712
39,606
41 ,351
43,086
44,905
46,818
48,815
-------
TABLE L~5 REVISED VOLUME FORECAST (WITH FAN SAVINGS) DIESEL - MEDIUM DUTY
Year
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Racpl inp
wUOw 1 IMC
Forecast
3,100
3,200
3,200
3,200
3,300
3,300
3,400
3,400
3,500
3,500
3,600
3,600
3,700
3,700
3,800
3,800
3,900
3,900
4,000
4,100
4,100
4,200
4,200
4,300
4,300
Volume Reduction
Model 1
0
0
0
0
0
0
0
446
459
459
472
472
485
485
498
4'98
511
511
524
538
538
551
551
564
564
Model 2
0
0
0
0
0
0
0
446
459
459
472
472
485
485
498
498
511
511
524
538
538
551
551
564
564
Model 3
0
0
0
0
0
433
446
446
459
459
472
' 472
485
485
498
498
511
511
524
538
538
551
551
564
564
-------
TABLE L-6 'REVISED VOLUME FORECAST (WITH FAN SAVINGS) DIESEL - HEAVY DUTY
Year
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Basel ine
L/ U
-------
APPENDIX M: FIRST-YEAR OPERATING COSTS FOR QUIETED TRUCKS
This appendix presents the basis for the data contained in Tables
7-13aand 7-l3b. Annual costs per truck were obtained by summing,
for each truck category, the depreciation, cost of capital, and operating
and maintenance expenses. Depreciation was computed using a 10-year
straight-line method. The cost of capital was assumed to be 10%. Annual
operating and maintenance costs were obtained from Tables 7-la and
7-2b. The figures in those tables were computed using average annual
mileages; since the first-year mileages are of interest, the numbers
in the tables were multiplied by the scale factors in Table M-l below.
The scale factors represent the ratio of first-year to average annual
mileage as obtained from analyzing U. 8. Bureau of the Census data
(see references, Section 7).
TABLE M-l SCALE FACTORS FOR COMPUTING FIRST-YEAR OPER-
ATING AND MAINTENANCE COSTS
Category Scale Factor
Gasoline - medium 2. 30
Gasoline - heavy 1. 83
Diesel - medium 1.43
Diesel - heavy 1.35
The first-year annual costs computed in this manner are shown in
Tables M-2 through M-4.
M-l
-------
TABLE M-2
2
i
ru
INCREASED FIRST-YEAR COSTS PER TRUCK - MODEL 1
( ) REPRESENTS SAVINGS
110-year straight-line depreciation.
2IQ% cost of capital.
3Obtained from Tables 7-2a, 72-b, and M-l.
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Depreci ation1
Cost of Capi tal 2
Quanti ty
and
Maintenance3
Without Fan Savings
0
0
$10.42
19.46
0
0
$10.42
19.46
0
0
$ 13.00
26.00
Total
0
0
$ 33.84
64.92
With Fan Savings
$ 7.00
.20
2.48
( 14.35)
$ 7.00
.20
2.48
( 14.35)
($121.00)
( 220.00)
( 90.00
( 303.00)
($107.00)
( 219.60)
( 85.12)
( 321.70)
-------
TABLE M-3
INCREASED FIRST-YEAR COSTS PER TRUCK - MODEL 2
( ) REPRESENTS SAVINGS
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Depreciation1
$12.50
12.50
26.42
48.76
$ 6.50
( 8.50)
16.82
15.16
Cost of Capital 2
Quantity
and
Maintenance3
Total
Without Fan Savings
$12.50
12.50
26.42
48.76
$ 21.00
35.00
13.00
238.00
$ 46.00
60.00
65.84
335.52
With Fan Savings
$ 6.50
( 8.50)
16.82
15.16
($221.00)
( 436.00)
( 90.00)
( 89.00
($208.00)
( 453.00)
( 56.36)
( 58.68)
'10-year straight-line depreciation .
210p cost of capital.
30btained from Tables 7-2a, 7-2b, and M-l.
-------
TABLE M-4
INCREASED FIRST-YEAR COSTS PER TRUCK - MODEL 3
( ) REPRESENTS SAVINGS
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Gasoline - medium
Gasoline - heavy
Diesel - medium
Diesel - heavy
Depreciation 1
Cost of Capital 2
Quantity
and
Maintenance3
Total
Without Fan Savings
$ 30.20
30.60
114.01
115-^3
$ 30.20
30.60
114.01
115.43
$ 48.00
81.00
176.00
485.00
$108.40
142.42
404.02
715.86
With Fan Savings
$ 24.20
9. "60
104.41
79.33
$ 24.20
9.60
104.41
79.33
($193.00)
( 385.00)
( 73.00)
( 157.00)
($144.60)
( 365.80)
135.82
1.66
110-year straight-line depreciation.
2IQ% cost of capital-
30btained from Tables 7-2a, 7-2b, and M-l.
-------
APPENDIX 1ST: IMPACT OK UOAI) TLMKS ON MANUKACTUKHUS Oh1
"NOISY" ENGINES
Acoustical consultants have estimated that, at the current state of
the art, it will take six years on a normal, orderly lead time basis
to quiet noisy diesel truck engines to a noise standard such as that
used for model 2. The time required is almost the same under model
3. Noisy engines now constitute 30% to 40% of the truck market. Most
of the noisy engines are produced by one of the major engine manu-
facturers with a strong market position. It would appear that the
stance of the manufacturer on this matter is that only a three-year
quieting program would be required and that he is not at a competitive
disadvantage with respect to quieting his engines.
Furthermore, it is possible that a priority R&D effort possibly
utilizing "new" as opposed to "available" technology could provide the
necessary modifications required to meet the standards in Model 2 in
three years. If noisy engines cannot, in fact, be quieted in three
years, a model 2 noise standard in that time frame will have impacts
on that particular manufacturer. However, the competitive position
of this major producer of noisy engines would be one of a short-term
competitive disadvantage. In the longer term, it is believed that
this producer has the demonstrated financial, business management,
and technical resources to compete effectively. Within a few years
of the effective date of the levels used in model 2, or possibly months,
the competitive disadvantage would be eliminated. Any one of a number
of factors could cause this:
N-l
-------
1. Results of a new R&D program that was not ready for the
effective date of Model 2 or its equivalent.
2. The possible introduction of new engines now in development,
which are quieter.
3. Implementation of a standard similar to that in model 3 which
imposes the same general level of technological requirements on quiet
engines as noisy engines. Prior to the effective date of such model 3
levels, some new trucks would probably incorporate these designs
in an orderly changeover of complete product lines. These trucks could
meet levels such as those "noisy" engines in model 2.
4. After three years have passed and the off-the-shelf technology
has been applied to permit use of "noisy" engines. On a priority basis
the normal, orderly lead time should be able to be cut for some large-
volume truck models to less than 3 years after enforcement of a
standard similar to that in model 2.
The reputation of the noisy engine producer with end users is very
strong. It is likely that this truck manufacturer would make an effort
to use his other popular engines, especially since the supply of overall
engines may be affected if the noisy engines cannot be utilized under
regular production conditions. It is, however, envisioned that the weak-
ness of this producer of truck engines will be taken advantage of by
other engine producers who could be expected to respond with a major
effort to penetrate the large and growing truck market. Again, since
the weakness will probably be only temporary, it is unlikely that there
would be long-term investments that would reflect the "noisy" pro-
ucer's absolute decline in the market.
N-2
-------
The noisy engine producer can be expected to make short-term
concessions and take other actions to protect his market position
against competitive inroads while bringing about a solution to the prob-
lem he may face by having lagged behind ofther truck engine manu-
facturers in the area of noise control.
According to U.S. Department of Commerce data, 439, 310 diesel
engines were produced in 1972. Of these, 41% were for the auto-
motive industry, of which almost 100% were for medium or heavy duty
trucks. Trucks are the largest single market segment for diesel en-
j^irn-H. Tin- rioiny cn^itifH roprcHcnl. I '>.% l.o 1 (i% <»f l.h<- total (|irnH
engine market. Currently, the;
-------
the opportunity in the truck market and the strong price competition
in the other markets from noisy engines which cannot be used in
trucks. Manufacturers of quiet engines will compute less in small
markets which show little growth opportunity.
3. The producer of noisy engines will shift sales emphasis from
the truck market to less noise-sensitive markets. To maintain volume,
price weakness will become common. Temporary noise rebates may
be made to truck manufacturers by engine manufacturers as partial
compensation for customizing required to use noisy engines.
Cooperative programs will be established with primary truck manu-
facturer customers to speed the development of such changes as cab
redesign, which will be required if noisy engines are to be used and,
at the same time, to prepare for lower future noise levels. The engine
horsepower specifications will be derated if this will improve noise
characteristics. The volume of noisy engine production will decline.
Market share of the truck market will decline; his profits will decline;
and unemployment will occur in plants producing noisy engines.
The extent of time over which the above scenario will take place
depends on the length of time required for the noisy engine manu-
facturer to become fully competitive again. Anything longer than three
to six months would result in a loss in competitive position that would
take years to regain.
N-4
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APPENDIX O: PROJECTIONS BASED ON TRUCK POPULATION AND
USE DATA
Many of tables and figures in Sections 3 and 8 were derived from
data acquired by the Bureau of the Census. In this appendilx, the
census data base and the operations performed with these data are
discussed.
DATA BASE
The Bureau of the Census has conducted surveys of a statistical
sample of trucks registered in the 50 states and the District of Col-
umbia in 1963, 1987, and 1972, in order to collect and publish data
on the characteristics and use of the nation's truck resources. A fac-
simile of the questionnaire used in the 1972 survey is included at
the end of this appendix.
The data obtained from this survey are available in the form of
a magnetic tape which consists of records for a sample of 99, 690 trucks
and the expansion factors necessary to extend this sample to obtain
estimates for the entire 1972 truck population.
The expansion factor associated with each truck is the number by
which the truck's statistical parameters are multiplied to estimate an
equivalent number of trucks in the U. S. Truck Population. For example,
there is a large number of pickup trucks in use, many of which have
similar physical and usage characteristics. Therefore it is not nec-
essary to sample as large a proportion of pickup trucks as, say,
medium dutydiesel trucks, since under these conditions, pickup trucks
would have a higher expansion factor than medium duty diesel trucks.
0-1
-------
Also, the Census Bureau samples by state, and the truck population
of the various states varies widely. To obtain equal confidence limits
on data sampled for each state, it is not necessary to sample the same
percentage of the state's truck population. Thus, data for each state
will tend to have separate expansion factors.
ANALYSIS OF DATA
It was felt that a sample size of 10,000 of the 100, 000 trucks on
the Bureau of Census tape was adequate for statistical reliability.
Accordingly, every tenth truck on the tape was sampled and sorted by
model year, category, and engine type as shown in the Table 0-1. Each
truck identified by model year, category and engine type is character-
ized by two parameters: the expansion factor F and the mileage
factor M . The mileage factor is the truck mileage driven during
the 12 months prior to the time the census questionnaire was filled out
TABLE O-l TRUCK IDENTIFICATION TABLE
Model
Year
1931
1932
1933
1972
Medium Duty Truck
Gasoline
F1931,l ^9-31,1
F1931,2. lMl931,2
t «
Diesel
Heavy Duty Truck
Gasoline
Diesel
0-2
-------
by each truck owner. In these factors, the subscript m represents the
model year, i the ith truck found in a particular truck category for a
given model year, and the superscript k designates truck category as
follows:
k = 1 represents gasoline engine medium duty trucks
k = 2 represents diesel engine medium duty trucks
k = 3 represents gasoline engine heavy duty trucks
k = 4 represents diesel engine heavy duty trucks
To project future truck population from past production estimates,
it is necessary to know the percentage of trucks that survive as a
function of age. This is computed from the equation
k
S = 10
j P t 1971-j,i
197 1-j (0'1}
Here, the subscript j denotes the age of the truck, and k is a truck
category superscript and not a power. Thus the survival factor S
is the fraction of trucks in truck category k still surviving j years
after production. The number 10 in the right hand side of Equation
(O-l) is used to extend the results from the 10,000 truck sample to
100,000 surveyed.
k
Thw terms F are simply the expansion factors for each truck in
a given truck category for a particular model year. As an example
of the application of Equation (O-l), consider the formula for com-
puting the percentage of gasoline engine heavy duty trucks (k=3)
surviving after five years:
0-3
-------
With the survival rate available from Eq. (A.I), the truck
population TC in calendar year c -for truck category k is computed
from the equation
Pk , Sk (0.2)
where P . is the number'of trucks in category k produced in the
c-J
year c-J. Eq. (0.2) represents the convolution of the survival
function S with the production function P.
Some of the curves in Section 8 show growth and decline of truck
populations manufactured in a several year period from model years
m, through nip. These populations are computed from
C~m2
Tk = V pk sk (0.3)
Ic,m1,m2 ^ c-J "j
j=c-m1
Thus, for example, the total truck population in 1990 that
is projected to be built and thus will meet an 83 dBA level under
the option 2 noise regulation can be computed by summing
T1990,1977/1977 + T1990 ,1977 ,19£ ~>+ T1990 ,1977 ,1977 + T1990,1977, 3980,
f . .
The average mileage M^ traveled by trucks j y?ars old in truck
category k is given by
r-
1971-J.i
Finally, the mileage-weighted acoustic energy level E produced by
the total population of trucks in calendar year c is computed as
(0.5)
j{
where NC_. is the noise level for a truck in category k produced
in the year c-J.
0-4
-------
i 'JI->A TC-200
(v-ld.7 I)
U.S. oi.i'Ai< t MI.in CM '.-'.MMi.nci:
HUlll A'l '» Till ll.HMJS
197? CENSUS OF TRAUSPOKTATIOM
TRUCK INVKinOi'Y AND USE SURVtY
INSTRUCTIONS
In correspondent:!; pcrl;iininr; to this
repoit, |ilr;isc include Slulc nnd
license number.
Hrtiiru ilic fonn in ihc enclosed pro-
nddtCKscd pa.stiifi liurenu is con'I •'
li.il. ll rriy LI-••iron only liy sworn Ci'hsus i-r-ij-loytft rnd ru .• !n'
ii'.'il i.:jlv ( coii-'i
iiliiin"d it) your lil''S orr iiMiuni': from lc(;nl pro':i:.~.s.
cor/cc( any cnut In numf and ntldtetm Inclmlinf. ZIP
(torn 1 - VEHICLE IDENTIFICATION
p correct any errors or omissions in the idcntificotion of the vehicfe.
Moke
Yrnr
mod':l
or cnpacily
State
License No.
'E: P.'rosc complete [his form whether or not you ore still the owner of [he-vehicle identified in item /.
Hem 2 - OWNERSHIP OF VEIIICI.I:
Are you still the owner (or license holder)
or lessee of this vehicle?
in
No ;
When did you sell, trade,
or otherwise disposc.of it?
Mniilh ntnl yc-iit
Item 3 - ACQUISITIOH OF VEHICLE
How did you acquire this vehicle?
i Q Purchased new
2 I I Purchased used — Speclty.yrat'
purc/inso
3 [ID Lcnnod from someone else
>> horn 4 - BASE OF OPERATION
a. What was the principal plucu from which
tho vehicle v/o* o;>'.-rated?
City en town
C'oulily
"EL
•I _
b. Woi thi» vnhicl« operated blmost enlitely
in the Stutc numeil in <4o?
Item 5.- VEHICLE MILES
ANNUAL MILES
a. What are the total mllos
this vehicle was driven
during tho.post'12 months?. .
Miles
'It.vrhifle was idle tot tlie yr-nr enter
"A'ono." 1C less than 12 months, c&timatc
probable miles lor a yoar.
LIFE TIME MILES
b. What ate the total miles
'this vehicle hoi been
driven since new?
Miles
C/vn r/fMirr/omnfi*r (oeionioter) teodinQ
or II net Inrlicalnd by niicoilainotor,
Aivri your lirst catimnlo.
Item 6 - LI AMID TO'OTHERS
WITHOUT DRIVER
Durir.(i the past 12 months, did you use
ihis vuhiclc MOSTLY for l*.t>ing or
renting (without driver) to others?
I Q^] No — Go to itom 7 on page 3
J Q Yea — Was this vehicle usually
leased or rented for:
1 [;') LOJS than 30 day»?.
7 LJ 30 days or
111.
-------
ltfiin.7 - MAJOK 1/IiL Or TliL li.Ji'.i; OiJ LGiil-llM
How was tKo vrliiilv ifOilly u^-il iluriiitj fbn |u«-.t 12 rr.oi.'•! <'/ JU i'oy«. n/iom you /<•/. -.oc/ (/ir tvfiii. /<.• (/!<••
f,V)
01 d Own farm or runcli or other
ii|;rirulturai activity
02 Q] I" forcHiry or
03 Q~) In mining or tj
04 [JJ In coriMlruction, huil'lin^s or roads
09 [^~] In manufacturing or processing
06 [~] In wlml<:snle uml/or rrtnil
07-Q] l-'or-liirr triinsiuirtatiou —
Includes Inicx.irf' services known u.s
druyiip,i;, locul- curti1.^)', liouschold
goods movers, convnuii or contract
motor crrrii-rs, coi.iiiu-rcial motor
cnriur.,, Iciiscd with diivcr, "owncr-
O|)CrolniH" under li.n:^1 or contract.
08 I
'"or personal truii!i|)ortntion —
Used in |>l(icc of .
-------
ho-,i 10 - GKUV, VLMICLC Wl-.IC.H T
f-li.-k (X) f»,%'/•; 1,-ir. it,1,1 la iifttic!,! //.«. minimum £ro.'.-i wn'',;fif s-nif-ty wlf.tit ol vcblclo fiJiu? carrivcl load)
it tv/i/c/i Iliiu tini.k at cnnbinuf/cn wuu Ciimrultxl Junnf t!n< p-'i •:< 72 iiit-ntlitj.
to
01 I J 6,000 HI |"H!t
02 ["] 6.001 lo 10.000
03 ("J 10.001 lo 14.000
04 Q'| 14/J-i! to 16.000
Ot[;| 16.001 to 19.500
06 Q 59.DOI to 26.000
OTCi^.COl i., 32,r/iO
OB QJ 32.00! to 40.000
09 QJ ',0.001 to 50,000
io(~|:'.o,ooi to co.ooo
11 CD 60.001 lo 70.000
1 2 [J 70.00! to Ud.OOJ
13 Q no.ooi to loo.ooo
»« Q 100.001 to 130.000
15 Cl 130.001 onil over
Item 11 - TYPE A!<[> SIZE OF BODY
Hnrk (X) O.Vf.' ocv t;<<»/>• fvpo i1/ I.':1.' cT;r.^i;i/ilion
most fioqtiently usul with the power unit.
BODY TYPE
01 [31 PitVup, | ant:l. i.iulii-:i(op. wnlk-in
0? UJ Pl:ii(oiin with »c!(k-d .ir-vii ."i -
HUili nri Ivd, f«.-tlili/<-r, lii:ic
or v.T.lcr ;-|jr'.-udet; Jumping
device, etc.
01 £J Other |ilntf',rm — inclnrtini; 'Unlrt,
(/ruin, llatlicd, low bed, (It |ircsued
center, <:ic.
04 Q] Onttlo rn< k (hoKH, cnlvcn. nnd
olhcr livi.-Mock)
05 (^] liinulalc-d ncn-rcfrigc-rntcH von
06 Q ] Insulotc'l icfrigcraled von
07 ["] Kurnitui'1 van
OB QJ 0|icu top vdii .
09 (~) All other cucloscd vnn»
10 QJ Ilcvi-rngv
It |"~] Utility (Iicdy r^uipf'p.d for mobile
rcpnir p-id service, e.p., Iclrphotic
line true'.:, clrulricpl utility, etc.)
Mnik (X) p/VC />ox to Indicate lunfitl, of loot!
or cnf.''jdty. U lu-o 3 F'l Winch or crane, oilier ll|pn wrecker
14 fj) Wrrckcr
•15 L 1 *>0'e or loRp.iDg
16 QJ Aulo trnn-.|io»l
Do not specify body si/e for tfiese types.
20 D L)ump truck or combination-
Ca|)iiciiy of duiop (wnler Ic.vcl without side bour>is) (cubic ynr '•»
21 [7J Under S 74 fj 10 toll. 9 27 [~] IP '«> '9 •''
22[_)5io6.9 25 [_) 12 lo 14.9 26 ("] 20 to 2y "
21 ['J7 lo 9.9 2C Q 15 lo 17.9 2'j Q) 30 or moi«
30 r I Tank truck or combiLntion (for liqtiids)-
I.iquid i:np.iciiy of li9
"["J n.OOOto 11.999
36 [~] 12.000 or motr
40 L..I Tuuk iiur k or coiiil>iniilion (lor dry l-ulk)—-—>-
Illy Lull fii|.in ily (<_nliu- fi-
41 f") I..-MM than 300
42[ _J300 lo 500
43 f."]600 10 «<)'.»
44 PI") POD 10 1.199
45 ['] 1.5(11) to 1.499
AS LJ '••"'•f'O 01 more
50 [_J duucrcte mixer.
C.'upncity of mixer (rtihir y-
hoi
nillii.f.ii I. •lily •!•••,' nl. r ymir vrhii.lr,.
1. 1, •:.-,,• ,.,il,., 1.1,1,1:1.,:,.,. '.. t .........
-------
r.hrm 12 - v. III',:LI: i n-i;
I* this vehiclr u single unit
O truck'tKiclor?
1 f ~) Siiip.N: "nil Irurk
r
>IUm 13 - AXLE ARRANGEMENT
M»rk (X) a\V. r».< /W illn*t,,.t<-x tl,» AXf.l-:
AI-:ltAM',lit,tl;NT ,nni most lievivrt mtil.
Jr-^q
vr« v-t'
rgnrfumai > -v i~^i
lic.n IL. - CAU 1YPL
Does (his vehicle hove a lilt cab?
' a YCS. z rj NO
3"
Jf none of the nbove Applies, pleo.sc inhem 14- POWERED AXLES
Mow mony drivinr) (poworod) axles tl&oi lhi»
vehlcU have? Kr,n,ri tamlnn, nxlrn n.. i^n «vf«».
» D One 3 f-j Three
3 |.~1 Two «'-- j.v,.,r ,, f>,.
20 — r.Vinc of pc-rj.ou U. conta'-i
iij; this report
Itrm 16 - TYPE OF FUEL
Whof lypn of fuel it used with thit vi-hiclo?
nc? |; | Di.M-1 3 Q 1 ,1'C or
> hem 17 -MAINTENANCE
Wlicn MAJOR icpairs v»cre needed on this
vehicle, were they usually done byr
i CH Yourself?
Truck dealer or foclory hronch? "
Own rcpoir ihop (set up specifically
for maintenance)?
Independent gorage?
Other? -
2
3
> Item 18 - ARHA OF OPERATION l_
V/herc wo* this vehicle MOSTLY operated?
Mark (X) OiVE box oji/y.
\ Q Mostly in the locol orco (in or nround the cily un-
BubuiLfi, or witliii, u short ditstniicc of the fr.n.i,
faclory, mine, or |>liicc vehicle is stationed).
2 Q No?i\ly ovcr-lhe-rood (I.cyond the local urea) bul
usually not more I ban1 :.'00 miles one wny to
the most distant stop from the place vrhiclo
is (ilotioncd.
s Q Mnstly ovcMhe.rood trips tliat usually are more
Iliah ?,00 miJcs! one *\n\ to the most distant
Mop fjom platr tlic vehicle is stationed.
> Item 19 - NUMUER-OF TRUCKS, TRUCK-TRACTORS
How mony trucVs, Iruck.lractors end Iroilors aro
you operating from the ba&n named in item 4 on
page I? Rc/iwf total numf.er mc/ucHnrt "10 vehlch
»-hieh you dotcribcd <*, (hi* quostionnniro.
Pickups, pnnrl.s, mulli-
elops or wiilk-inn ....
Other truckn . .
Truck-tructorB
Trni|pfsfsi:ini- nnco,/..-J
To I u |
31
Vrplicuiv (At»i> c
number, extension)
™'J^M-rM«:,
- ' " "
of pi-rsr.i, prrp^iii^ li.il. i -porl
'I ilJ
0-9
DalL
------- |