JACXFAU-78-189-3
GUIDELINES AND SAMPLE TRAINING WORKBOOK FOR
POLICE ENFORCEMENT OF NOISE REGULATIONS
EPA Contract Number 68-01-4701
April 1979
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Noise Enforcement Division
Washington. D. C. 20460
Submitted by
sJACK FAUCETT ASSOCIATES
,5454 Wisconsin Avenue
Chevy Chase, Maryland 20015
301/657-3223
-------
JACKFAU-78-189-3
GUIDELINES AND SAMPLE TRAINING WORKBOOK FOR
POLICE ENFORCEMENT OF NOISE REGULATIONS
EPA Contract Number 68-01-4701
April 1979
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Noise Enforcement Division
Washington, D. C. 20460
Submitted by
JACK FAUCETT ASSOCIATES
5454 Wisconsin Avenue
Chevy Chase, Maryland 20015
301/657-8223
-------
TABLE OF CONTENTS
TITLE PAGE
I. GUIDELINES 1
A. Conduct of the Training Sessions 1
B. Adaptation of the Sample Training Workbook . 6
n. SAMPLE TRAINING WORKBOOK 7
A. Introduction 8
B. List of Attendees 9
C. Course Schedule and Content 10
D. Applicable Motor Vehicle Noise Regulations 15
E. Motor Vehicle Noise Enforcement Field Manual 16
F. Summary of Field Measurement Procedures 23
G. Motor Vehicle Noise Measurement Data Sheet 26
H. Applicable Non-Motor Vehicle Noise Regulations 28
I. Stationary Noise Measurement Data Sheet 29
J. Glossary of Terms 30
K. Sound Levels of Typical Noise Sources 35
L. Sound Level as a Function of Distance
for a Small Source 36
M. Addition and Subtraction of Sound Levels 37
N. Operation of GenRad 1565-B Sound Level Meter 41
0. Sample Courtroom Testimony 42
P. Evaluation Sheet 46
Q. Examination 48
R. Certificate 52
JfA
-------
I. GUIDELINES
A. Conduct of Training Sessions
1) Time and Duration. If possible, the sessions should be scheduled for a season of
the year when it is warm and unlikely to rain. In most jurisdictions, noise control
laws provide that legally binding measurements cannot be made in the rain. In
addition, rain damages microphones and interferes seriously with the field
demonstrations and experimentation, which are the parts of the course in which
the trainees will learn most of what they retain. Every course should have a plan
as an alternative to the outdoor sessions, in case of rain, but the course will be
less effective if the rain plan must be used. A course in which the trainees are
expected to learn to enforce both motor vehicle and non-motor vehicle noise
control laws should last four 7- or 8-hour days. If only motor vehicle laws are to
be considered, two 8-hour days may suffice. The schedule in the Sample
Workbook covers two days; if there is additional time, it should be spent in
practice in the field.
2) Location. The training facilities and environment of a police academy are ideal.
The officers, especially if they are in uniform, will not disturb other activities at
an academy as much as they might in a civilian site. In any facility there should
be good access to open space for demonstrations so that neighbors are not
disturbed by noisy demonstrations; parking facilities should be ample for the
trainees' cars; and eating facilities should be on site or close by. A police
academy satisfies all of these desirable characteristics.
3) Instructors. As much of the training as possible should be done by police
officers. An officer should do the introduction. An acoustical engineer is
perfectly acceptable as the trainer on the principles of sound and on the
concepts of the sound level meters. Hands-on experience and field demonstra-
tions should be given by experienced police officers. The other portions of the
course may be given by civilians, but, if a qualified and skilled police officer can
be found, he or she will more likely be a more effective trainer. Try to have one
such officer-trainer for each 3-5 trainees.
JFA
-------
4) Trainees. If at all possible, the trainees should be police officers who have
volunteered for training and for duty as noise control law enforcers. They should
have been given some advance notice that instruments will be used and that
some technical inclination and experience will be helpful although not essential.
A suggestion that noise level measurements are about as complicated as
photography may be helpful.
5) Training Materials. The trainees should be furnished with a complete text of all
the regulations, procedures, forms, and similar materials that they will use for
noise enforcement. A workbook like this one is a valuable place to keep all the
training materials together. The glossary, summary of field measurement
procedures, data sheets, and sample courtroom testimony in the sample
workbook should be applicable to all training sessions.
6) Instructor Preparation.
a) Have thorough familiarity with all aspects and interpretations of the
regulations that will be taught. All legal issues should be resolved ahead
of time so that the instruction can be authoritative and specific. Know
the limits of the police authority and the names of other agencies that
enforce noise laws.
b) Be familiar with the locality (local customs, conditions and problems) so
that the presented materials have a local flavor and local validity. Know
the local police department's present methods of handling noise
complaints, of investigating noisy fights and disturbances, of responding
to burglar alarms, of issuing permits for emergency repairs and
construction, of stopping and checking motor vehicles, of issuing
citations, of cooperating with State police officers in motor vehicle noise
cases, and similar details.
c) Know the organization, training, assignment procedures, and principal
officers of the local police department. The information in this and the
proceeding paragraph often need not be stated or be obvious in the
JRX
-------
presentations, but familiarity with it will help to avoid errors on which
the local trainees may remark and which therefore will weaken the
forcefulness of the presentations.
d) Prepare slides that show local scenes as examples of noise enforcement
situations. Use pictures of local noise sources, local sites which are
suitable/unsuitable for noise measurements, local customs or events that
may be important to noise abatement, and local people making noise
measurements.
e) Investigate, arrange, and check out thoroughly all the training equipment,
training sites, alternate facilities and equipment, transportation facilities,
food facilities, and similar arrangements before the training sessions.
f) Develop an alternative plan in case it rains. This plan should include
indoor simulation of field conditions with recorded noises.
7) Audio-visual Aids.
a) Use numerous, informal color slides. Be sure that the projector and all
the slides are suitable to allow showing the slides with the lights on.
b) Sound recordings are very effective in a course on sound and noise. Use
demonstrations of pure tones at the same intensity and different
frequencies as a substitute for explaining equal loudness contours. Show
the sound of pass-by vehicles, of stationary noise soures, of intermittent
noises, of impulse noises, and so forth.
c) Avoid graphs; rely on tables for correction factors, etc. and use pictures
to demonstrate distance relationships.
JFA
-------
8) Contents of the Presentations.
a) At the beginning and at intervals throughout the course tell the trainees
what the course objectives are and what the trainees should be able to do
at the end of the course. Remind them of what will be expected of them
at the course's conclusion.
b) Communication is as important as technical accuracy, so avoid long
specialized words. Say "spreading" or "travel over the ground" instead of
"propagation". Say "decay" or "reduction with distance" instead of
"attenuation". Avoid referring to decibels as logarithmic units, just say
they are units of sound pressure.
c) Before the process of addition and subtraction of sound levels is
explained, explain why one needs to add and subtract them. This part of
the presentation is frequently the most confusing to laymen.
d) Work in whole numbers of decibels as much as possible.
e) Explain the A, B, and C scales on the sound level meter, but concentrate
on the A scale. Explain dB(A) as a form of sound measurement that is
chosen because it measures noise as the ear responds to noise.
f) Give the names and addresses of the organizations that can help with the
selection and calibration of equipment and with further technical help.
g) Explain how to get assistance from the regional EPA noise representative
and the services which one can expect from such a representative.
h) Play down the problem of appearance in court. Explain that most cases
never get to court. Motor vehicle violations do not involve penalty points
so usually the cases are unopposed. Other noise cases usually involve
fines so small that they are not contested either. TeU the trainees to be
prepared to answer the questions in the material on court appearances in
the Workbook and to discuss this material with the prosecuting attorney.
4
JBV
-------
9) Demonstrations and Field Work.
a) Have a full set of equipment, including windscreen, sound level meter,
calibrator, headphones, screwdriver, and wind gauge for each 3-5 trainees
and give a set to each police instructor. During the lecture on the sound
level meter, let each police instructor begin to take out and demonstrate
the equipment as the lecturer describes the components. Then let 3-5
trainees cluster around the police trainer who will take over from the
lecturer and begin the hands-on experience that will lead to the outdoor
demonstration and participation experience. During the outdoor demon-
strations set up the equipment and monitor sample vehicles as they pass
by the sites. Later, if it is possible, let the trainees choose an actual
enforcement site, set up their equipment, and make measurements of
vehicles in normal traffic.
b) Use the kind of meters that the police will use, but avoid demonstration
training that uses digital displays on sound level meters. Train the police
to read the swinging needle and to relate the meter movement to what
they hear. Emphasize the advantage of and the need for listening
carefully to augment and to improve the knowledge of the acoustical
situation as it is measured on the meter. A digital meter inhibits this
learning. If the police are going to have digital meters with the peak hold
feature, introduce these meters at the end of the training after the habit
of watching the needle has been learned. (Non-digital meters often may
be borrowed from EPA.)
c) Show, on actual vehicles, where defective components are or might be.
10) Concluding Procedures.
a) Give examinations on the course work covered at the end of each day.
Give an open book, multiple-choice test at the end of the course. An
example is given on pages 48 through 51 of this document.
-------
b) Ask the trainers to fill out an evaluation sheet such as the sample given
on pages 46 and 47 of this document. It will allow the trainees to express
their thoughts and give you valuable feedback.
c) Issue a certificate at the end of the course, but send it to the graduate via
the chief of police, to whom the graduate's grades in the course also
should go. If the certificate can be one from a regular police academy, so
much the better. (An example is given on page 52 in this document.)
B. Adaptation of the Sample Workbook
The remainder of this volume consists of a sample workbook which can be adapted to
suit the specific laws, regulations, requirements, and conditions of each training session
that includes instruction in making sound level measurements.
Unless materials are available which are more specific to the local situations, the
following sections from this workbook can be included verbatim in the adapted
workbook:
Summary of field measurement procedures
Glossary of terms
Sound levels of typical noise sources
Sound level as a function of distance from a small source
Adding and subtracting sound levels (a chart for approximate answers)
Operation of the GenRad 1565-B sound level meter
Sample courtroom testimony
Course evaluation sheet
In the remaining sections the adapted workbook must include materials which are
specific to the jurisdiction for which the training is intended. At the completion of the
course, it is suggested that the trainees should be given an examination similar to that
shown on pages 48 through 51 and a certificate like that shown on page 52.
JfA
-------
n. SAMPLE TRAINING WORKBOOK FOR
POLICE ENFORCEMENT OF NOISE REGULATIONS
A. Introduction
B. List of Attendees
C. Course Schedule and Content
D. Applicable Motor Vehicle Noise Regulations
E. Motor Vehicle Noise Enforcement Field Manual
F. Summary of Field Measurement Procedures
G. Motor Vehicle Noise Measurement Data Sheet
H. Applicable Non-Motor Vehicle Noise Regulations
I. Stationary Noise Measurement Data Sheet
J. Glossary of Terms
K. Sound Levels of Typical Noise Sources
L. Sound Level as a Function of Distance for a Small Source
M. Addition and Subtraction of Sound Levels
N. Operation of GenRad 1565-B Sound Level Meter
O. Sample Courtroom Testimony
P. Evaluation Sheet
Q. Examination
R. Certificate
JfA
-------
INTRODUCTION
(Sample)
This workbook is an aid to the training sessions and a supplement to the classroom
experience. The two-day sessions will cover the following topics:
Principles of sound and noise
Use of measuring instruments — explanation and hands-on experience
Use of measuring instruments — field experience
Regulations and measuring procedures for motor vehicles
Enforcement procedures for motor vehicles
Field training at a motor vehicle noise measurement site
Regulations and measuring procedures for non-motor vehicle sources
Enforcement procedures for non-motor vehicle sources
Enforcement problems and their solutions
Preparation for appearance in court
Review and examination
Evaluation of the course
At the conclusion of the sessions, the trainees are expected to be able to enforce all of
the provisions of the laws and regulations that are assigned to them for enforcement.
This workbook contains complete texts of these laws and regulations and several items
of reference information, checklists, definitions, and samples of forms that will be
referred to in the training and will be useful after the training sessions are completed.
Several of the tables and charts give only approximate values for the answers to
problems requiring calculations. These tables and charts are suitable for determining in
the field whether there is a violation.
This training session is sponsored by .
-------
LIST OF ATTENDEES
(Sample)
(Give name, rank, department, address, and telephone number)
Sgt. Joseph K. Howell
Troop H
Pennsylvania State Police
Harrisburg, Pennsylvania 17120
(717)308-1500
JFA
-------
POLICE ENFORCEMENT OF NOISE REGULATIONS
COURSE SCHEDULE AND CONTENT
First Day
8:00 REGISTRATION
8:15 INTRODUCTION
1. Welcome
2. The Purpose of the Course
a) Training
b) Improvement of course
3. The Purpose of Noise Enforcement in General
4. The Legal Authority for Noise Control Laws
5. The Reasons for Police Involvement
6. A Preview of Course Content
7. Introductions of Teaching Staff and Assistants
8:30 PRINCIPLES OF SOUND AND NOISE
1. Sound
a) Definition
b) Causes
c) Spreading and decay
d) Characteristics
i) intensity (decibels and sound level)
ii) frequency (hertz)
iii) time variation
2. Noise
a) Definition
b) Sources
3. General
a) Visualization and examples of types of sound
i) steady
ii) slowly fluctuating
iii) rapidly fluctuating
iv) intensity and frequency variation
10
in.
JA
-------
b. Range of human hearing
i) intensity
ii) frequency
c) Loudness curves
d) Frequency weighting curves
i) A
ii) B
iii) C
iv) A-Weighting
e) Sound spreading and decay
i) types of sources
ii) reflecting surfaces
iii) ambient sound level
iv) barriers
v) directivity
f) Adding and subtracting decibels
g) Tape recordings of different sounds
h) Question and answer period
10:15 BREAK
10:30 USE OF MEASURING INSTRUMENTS
1. SOUND LEVEL METERS used by Police Departments
2. Points at Which Sound is Measured
3. Sound Level Meters
a) Components
i) filter
ii) fast/slow response
iii) scale
iv) attenuator
v) microphone
b) How to read a sound level meter
c) Types of sound level meters
4. Acoustical Calibrators
5. Basic Measurement Conditions
a) Microphone height and position
b) Reflecting surfaces
c) Ambient noise level
d) Weather (wind, rain, or snow)
e) Meter settings
JFA
-------
6. Potential Problems
a) Damaged diaphragm
b) Humidity
c) Out of calibration
d) Low batteries
7. Hands-on Measurement Experience With Different Sound Sources
8. Question and Answer Period
12:00 LUNCH
1:00 USE OF MEASURING INSTRUMENTS —
FIELD EXPERIENCE
1. Examine Features of the Site
2. Set up Sound Level Meter on Tripod
3. Calibrate
4. Measure Wind
5. Measure Distances
6. FiU Out Data Sheets
7. Measure Test Vehicles and Ordinary Traffic
8. Report Results
2:30 BREAK
2:45 MOTOR VEHICLE NOISE REGULATIONS
1. Provisions of Specific Regulations
a) Applicability
b) Definitions
c) Noise limits
d) Administrative provisions
e) Instrumentation and calibration
f) Measurement techniques
g) Ambient conditions
2. Field Work
4:30 REVIEW
4:45 EXAMINATION
12
JfA
-------
Second Day
8:00 NON-MOTOR VEHICLE (OR STATIONARY)
NOISE REGULATIONS AND FIELD MEASUREMENTS
1. Provisions of Specific Regulations
a) Curfews and duration limits
b) Restrictions on locations of noise sources
c) Equipment restrictions
d) Nuisances
e) Audibility
f) Noise levels at specific distances from
the source
g) Noise levels at a property line
2. General Considerations
a) Administrative provisions
b) Instrumentation and Calibration
c) Measurement techniques
d) Ambient conditions
9:15 NOISE ENFORCEMENT PROCEDURES
1. Motor Vehicles
2. Non-Motor Vehicles
10:15 BREAK
10:30 NOISE ENFORCEMENT PROBLEMS
AND SOLUTIONS
1. Types of Problem Sources
a) Motor vehicles
b) Chain saws
c) Mini-bikes
d) Big-wheel bikes
e) Air conditioning units
f) Portable air compressors
g) Stereos
h) Burglar alarms
i) Parties
j) Dogs barking 13
JfA
-------
2. Problems in Ambient Noise Measurement
3. Multiple Sources
4. Moving "Stationary" Sources
a) Dump truck
b) Lawn mower
5. Between Dwelling Units
11:30 PREPARATION FOR COURT APPEARANCE
1. Training and Experience
2. Proper Technique
3. Proper Law Interpretation
4. Proper Data Records
5. Sample Questions
12:00 LUNCH
1:00 FIELD TRAINING AND OBSERVATIONS
AT A MOTOR VEHICLE TEST SITE
1. Wind Speed
2. Ambient Levels
3. Roadside Set Up and Site Qualifications
4. Roadside Noise Measurements
5. Filling Out Data Sheets
4:00 REVIEW
4:30 COURSE EVALUATION
4:45 EXAMINATION
14
-------
Aan*3 A
7. 73LANSPORTA7ION
DSPARTM2NT OF
7RAN3PORXATION
CHAST3R 450. ESTABU3H2D
SOUND LEVEI.S
TABLE OK CO.VTE.NT3
Part 1. C*n»raJ
tw
4VI \. 1'i'rp"-*-
r.rl 2. N»lx Umllj
4iO.lt. Vehicular nul«« ttmii». .
44O 13 ,M«;>
P»rt S. A4mlnl»lr»lt»« S»roTU»n«
lnip»«lon .r>d examination of motor
ci..
420.31.
inoa.umiwr.l i-y
4M..U. Wlnd»cr»»n».
Tirl I. Mi»urrmenl of
APPLICABLE MOTOR VEHICLE REGULATIONS
(Sample Page)
(b) Exception*. Th*se regulation* do
nut apply to.
(1) fire equjpma.-il
(2) rncln^ vehicle* whicijora operated
in an organized racing or competitive
event conducted under a permit Issued
by local authorities.
S 450.2. Definitions.
Ground cover — Any of various lokv,
dense-growing plants, such as ivy, myr-
tle, low weeds, or brush.
Hani te'st site — Any test sila havinj
the j- t li.
AinMfiil onidlllun*.
ijw;inmi jn.i iiix-niii
l »>•"•'"•
I Irwl .lK-n~
•JSO.3I. Vlcrophwv* d)«i.iii« coirnctlon futmr-.
4X1 ii Gn'und »iirC.«.«r con«l!.m fjvl»i».
(60.33 Coiii|iul4llnti nl open »!!«• rniulii->m-n
iliirr
va7)^ls» »2»r41ed ort any highway to
d*termlr* w?wth*r tho»« vehicles afs
constructed, equipped, maintained, and-
operated to conform with th« estub-
llalied sound levels Bet forth in section
450.11 of this regulation.
Microphone point — The-
location on th« canter of the lan'a. 6*
travel that is closest to the microphaa*.
Reltitii-fly flat '— A noise measure-.
ment site which does not contain signifi-
cant concave curvatures or slope rever-
sals that may result in the focusing of
sound waves toward the microphone lo-
cation point is relatively Cat.
Soft test situ .— Any test site havjdj
the ground surface covered with grfJs,
other ground cover, or similar absorpiivs
material for 1/2 or more of the distance
between the microphone target point'
and the microphone location point.
Traffic raiting -— Any longitudinal
hlgh-way traffic barrier system Instated
along the side or median of a highway.-A'
traffic railing must hnve at least 35% of
its vertical height, from the ground sur-
face to th« top of the racing, open to f>e*
space iu order to qualify as an acceptable
object within u noise measurement tsat
Kite. Posts or othar. discrete supports
shall be ianored when ascertaining open
free hpace.
Table 1. Maximum I'ermifxll'lc Sound I^vel KradinXh <
Highway operations test
soft
(A)>
."J5 ini/li
or less
site
Alwve
35 mi/h
hard site
35 mi/h
or U-ss
Above
35 mi/h
(I) Any motor vcliii:li: with a
manufacturers gross vi-hich-
weight rating of G. 000 JJOIHI.IS
or more and any conit>iii;i'i»n "'"
vehicles tnwed by such motor
i'J.1 Any iiiiiinit vi N-
u ttiiilnr tlH\«-n « y« If
(3) Any othf r motor vehicle
/and nny comhin.ifion of
towed hy sucli motor
limn
8:1
76
82
88
H-I
78
92
MH
S'l
15
Vehicle refrre.nct poixl — Th» loca-
tlnii mi ihr vshlclr mpd to dtterininr
whrii iIn- vehicle In ut any oflhi? poiiMs
on ttiL- vehicle path. Th? primai'V vehicle
ri-liTi-iict: )H)!nt is the CrOiu of ()itf vehiclB.
For vehicles' with a gro-is vehicle rating
of G.OUO pounds or more, where the dis-
tance from the Front of the vehicle to the
exhaust outlet is more lhaii 16 it;et, the
secondary vehicle rcfrrenct' polpt 1» the
exhaust mulct.
Part 2. Noise LimiU
5 450.11- Yeuicalar noiw HmiU.
(a) Prohibition. No perso
ate eithar a motor vehicle or cpmbfca arksn
of vehicles bi a type 8ubi*ct'^ro rssiitrs-
don at any time or under ajiy conditjoo of
grade, load, acceleration or deceleration
in such a mariner as to exceed the follow-
ing noise limit for the category'of.rnfttcr
vehicle within the speed limits specified
in Table 1.
(b) Measuretrtrnt distance. The noU-
limlts established by ihis section shiili ;, •
based on a distance of 50 feet from th .
center lane of travel within the speed
limit specified in this section. Meas-
urements at distances closer than 50 feet
from the crenlrr of (hi- lane of travel may
be made. In such a case, the measuring
device bholl be so calibrated as to provide
for measurements equivalent to the
noise limit established by this section
measured at 50 feet.
(c) Trucks. A truck, truck tractor, or
bus that is not equipped with an identifi-
cation plate or marking bearing the
manufacturer's name and manufactur-
er's gross vehicle weight rating shall be
considered as having a gross vehicle
weight rating of 6,000 pounds or more If
the unladen weight is more than 5,000
pounds.
(d) The rules in this part do not apply
to —
(1) The sound generated by a warning
device, such as a horn or siren, installed
in a motor vehicle, unless such device is_
intentionally sounded in order to pre-[
elude an otherwise, valid- noise emission
measurement;
(U) An emerxenoy vehicle, sm-h-.as a
lire department vehicle, poliii- \ehit-U-.
. it i » _ t * - .. "—'- ....U. :..!..
li lood-ileli very"' vehicle,
armed forces iimergency vehicle,, one
private vehicle of fire or p^Jif K chief ur
assistant chief or ambulance corps
CDimrsander or assistant confmander. or
of a river rescue commander or other ve-
hicle*'designated by the Pennsylvania
Stnte.' Police as emergency vehicles,
when-responding to an emergency call;
'(3} 'A shoyv plow In operation; or
.(4}',rfje .sound generated, by special
niobVie equipment which Is normally op-
erneed only when the motor vehicle on
which it is. installed Js slopped or .is
operating at a speed of 5 miles per luuir
or less, unless such device is intention-
ally operated at speeds ure.itcr titan 5
•u.p h. in order l» |ir«-<-lii(lt* an «
valid noise iif.inurement.
JfA
-------
MOTOR VEHICLE NOISE ENFORCEMENT FIELD MANUAL
(Example)
This manual has been designed to supplement the provisions of the Pennsylvania
Department of Transportation Regulations Title 67, Chapter 450, "Established Sound
Levels", effective August 27, 1977. This manual is to be used as a guide only and is not
sanctioned or approved by any official agency of the Commonwealth of Pennsylvania.
CONTENTS
1. Purpose and Introduction
2. Equipment Requirements
3. Site Selection
4. Equipment Set-Up and Calibration
5. Meter Operation and Citation
6. Reporting Requirements
7. What to Look For
8. Arrests
16
JFA
-------
1. Purpose and Introduction
This field manual will assist police officers in enforcing the motor vehicle noise
regulation. It outlines how to select sites for enforcement, how to set up a
checkpoint, and how to operate the noise measurement equipment.
2. Equipment Requirements
a) Approved Sound Level Meter
b) Tripod (optional)
c) Acoustical Calibrator
d) Cable (optional)
e) Wind Gauge
f) Windscreen
g) Screwdriver
h) Data Sheets and Pens
i) Headphones (desirable)
3. Site Selection
a) Select an upgrade site.
b) Consider stop and go traffic.
c) Determine if the site is "hard" or "soft".
d) Measure the site dimensions and mark the microphone positions so that
the site can be used easily for future noise measurements.
e) Note and record appropriate site characteristics.
4. Equipment Set-Up and Calibration
a) If possible, set up the microphone to monitor more than one lane of
traffic.
b) If the microphone attaches to the Sound Level Meter via a cable, be sure
all connections are tight.
17
-------
c) Check batteries of the calibrator and Sound Level Meter.
d) Turn the meter on and allow it to warm up for at least 1 minute.
e) Set the weighting scale to the position the manufacturer specifies for use
with the calibrator; this is commonly the "A" scale.
f) Set the meter response to "fast".
g) Set the meter to the appropriate measuring range.
h) Attach the calibrator to the Sound Level Meter and turn on the calibrator.
i) Adjust the meter with screwdriver to coincide with the calibrator output.
j) Recheck the meter with the calibrator at appropriate intervals until
meter stabilizes. If it varies by more than 0.3 dB, the meter or
calibrator is probably not functioning properly.
5. Meter Operation and Citation
a) After the Sound Level Meter is calibrated and the calibrator is removed
and turned off:
• Set the meter on the "A" weighing scale.
• Attach the windscreen.
• Preferably when there is a lull in traffic, measure the ambient
level and record it. If the level is 10 dB less than the appropriate
regulation, measurements may proceed.
• If a single lane is used and the measurement distance is less than
50-feet re-calibrate and adjust meter to meet distance correction.
18
-------
• Observe traffic flow; if the flow is such that the meter swings up
and back at least 6 dB for noisy vehicles, measurements may
proceed.
• If multiple lanes are used, note the appropriate noise limit for each
class of vehicle for each lane, using the proper combination of site
(hard or soft) and of legally permissible speed (35 mph or less or
above 35 mph).
• Most vehicles will not exceed the noise limits; hence, subjectively
you'll be able to note the louder vehicles that may be in violation
of the regulation. Thus you'll probably be able to hear the vehicles
coming.
Watch the sound level meter as the loud vehicle approaches (there are to be no
other vehicles in the measurement area); the meter should swing upwards by at
least 6 dB. Note the maximum sound level when the vehicle is in the
measurement area.
Subtract tolerance from the measured sound level and compare this "new" level
with appropriate noise limit. Also, watch the meter to see the needle reading
reduce by 6 dB before it starts increasing for the next vehicle.
If the needle does swing sufficiently, and if the appropriate limit is exceeded,
the vehicle is in violation and a citation or warning can be issued.
You should be able to identify visually the source which is making the noise that
violates the limits.
6. Reporting Requirements
In order to back up your citation or to develop a retest, the procedure,
instruments, and site conditions must be documented. Following are minimum
reporting requirements:
a) Day, date, time
19
JB\
-------
b) Site location, description, topography and unusual site features, sketch
with microphone location and height described
c) Equipment used, by type of equipment, model, manufacturer and serial
number
d) Calibration check completed
e) Meter settings
f) Ambient noise level
g) Description of the vehicle and driver in violation, license number, driver's
name and address
h) Sound level permitted and sound level measured. Tolerance allowed
i) Weather conditions
7. What to Look For
a) Trucks
The major sources of noise are from the exhaust, the tires, and the engine
area. The regulation requires a different vehicle reference point if the
exhaust is more than 16 feet from the front of the vehicle. Another
source of noise is that produced from the load or equipment attached to
the truck (cement trucks are typical of this type).
b) Automobiles
The major sources of noise are from faulty exhaust systems, snow tires at
high speed, exhibition speed, or "peeling".
c) Motorcycles
Exhaust noise is generally the predominant noise source; on occasion the
engine noise might be significant.
20
-------
3. Arrests (This section is for illustration and suggestion only.)
Cite the operator of the motor vehicle:
a) Sound level limit exceedence
b) Equipment malfunction
Citations are written on a regular traffic summons. The title of the citation is
"Excessive Noise dB(A)" or "Improper Muffler. . . dB(A)". Fill in the
blank with the meter reading.
If the muffler or pipes are defective or in need of repair, cite using the defective
equipment section of the motor vehicle code. This section requires the violator
to fix the vehicle and to bring it in for a retest. You will have to tell the
violator about the mandatory retest and to give him or her a retest schedule.
If the excessive noise is created by intentionally modified equipment (for
example, removing the baffles from motorcycle pipes or making a cutout in the
exhaust pipe ahead of the muffler), cite using the modified equipment section of
the motor vehicle code.
If the excessive noise is created by the way in which the violator drives the
vehicle, cite using the established sound levels section of the motor vehicle code.
Juveniles will have to be cited under the appropriate state code. Even though
there is no retest provision in this section, treat them the same as under City
Code — that is, if the muffler is old and needs repair, give them a chance for a
retest. But if they're running straight pipes or otherwise intend to make noise,
do not give them a chance for a retest.
For those who can take the retest, set the court data at least seven days in
advance. This gives them a chance to repair the vehicle and bring it to the
retest site. For those who do not get a chance for retest, set the court date as
for any normal traffic summons.
21
JA
-------
Keep in mind that you can make arrests for vehicles in traffic lanes other than
the closest one. But make sure there is no vehicle in the lane between you and
the noisy vehicle. Once again, make sure you can identify by ear which vehicle
is causing the excess noise.
9. Retests
Retests should be allowed with discretion. For intentional violators, there is no
need for retesting nor is there need to retest vehicles that are obviously
defective. Retest is recommended if no obvious defect exists or if the repair or
replacement of the noisy element (like snow tires) obviously is not going to abate
the noise.
If practical, retest should be performed at the site where the original violation
occurred. The vehicle and microphone should be in the same location as the
original test and operated in substantially the same manner.
22
-------
SUMMARY OF FIELD MEASUREMENT PROCEDURES
1. Identification;
Record time, date, operator, and site identification on the data sheet.
2. Are site conditions OK?
a. Clear zone requirements met?
b. Ambient sound level requirements met?
c. Test site ground OK?
d. Hard- or soft-site computations made?
e. Reflecting objects considered?
3. Measurement Location and Site Layout;
Sketch site layout and proximity to any major nearby sources (i.e., streets, air
conditioner). Record all significant dimensions, topographic details, heights of
source, presence of nearby reflecting surfaces and foliage (if significant, note
density and type of growth). Also note ground cover in immediate proximity of
measurement position and walls, fences, hedges, etc. between any major nearby
source and measurement location. Be sure microphone height is correct.
4. Weather Data;
Weather conditions:
• No high winds?
• No precipitation?
The following weather information should be noted and recorded on data sheet:
• Temperature | Only if either approaches the limits of the range in
• Relative humidity j which the manufacturer recommends use of the
equipment.
• Wind velocity and approximate direction
• Any precipitation and water, ice, or snow on the pavement
If the measurement period is lengthy, note variations in weather data during the
measurement period.
23
JA
-------
5. Source Activity;
Note general activity of major nearby noise sources (i.e., traffic flow, air
conditioners operating, aircraft flyovers, etc.).
6. Basics of Sound Level Meter Operation;
(Refer to instruction sheet for specific meter type.)
a. Check batteries on meter and calibrator before each calibration.
b. Always calibrate before and after measurement (For long measurement
periods, intermittent calibrations are appropriate).
c. Use windscreen.
d. Measure ambient noise level.
e. Measure source.
f. Fill out data sheet.
g. Recheck calibration.
7. Annual Calibration (suggested);
On an annual basis sound level meters and calibrators should receive a laboratory
calibration in accordance with the manufacturer's specifications. This
calibration should be traceable to the National Bureau of Standards.
An inspection label should be attached to each instrument set stating when and
where the calibration was performed.
8. Meter Settings;
For vehicle noise measurements, use A-weighted filtering and "fast" response.
9. Meter Scale — Measurement Range;
Set attenuator so that readings are made as near mid-scale as possible. This
insures maximum readability and minimizes chances of overloading the meter.
10. Avoid Wind Noise;
Always use a windscreen for outdoor measurements. Curtail measurements when
the steady wind speed exceeds 12 mph.
24
-------
11. Precipitation;
Do not conduct measurements when precipitation is falling.
12. Sound Level Meter Orientation;
The meter should be oriented relative to the noise source being measured as the
manufacturer suggests. Grazing incidence microphones require that the axis of
the microphone be perpendicular to the line of sight from the source to the
meter. Perpendicular incidence microphones require that the meter be pointed
directly to the source. Refer to the instruction manual for the particular
requirements of the sound measurement instrumentation being used.
25
JB\
-------
MOTOR VEHICLE NOISE MEASUREMENT DATA SHEET
Date
Time Start Test
Sound Level Meter: Manufacturer
Microphone: Manufacturer
Calibrator: Manufacturer
Meter Check;
Batteries
Fast Response
Calibrator Check:
Batteries
Model Serial #
Model Serial #
Model Serial If
Windscreen
A-Weighting
Weather: Wind
Temperature
Humidity
Calibration at Start
dBat
hertz
Site Sketch
Indicate North
Site Location
If prequalified site,
indicate designation of site.
Calibration at End
Time End Test
Batteries check SLM
Equipment turned off
dB at
D
D
26
hertz
Calibrator
D
D no
Operator
JRX
-------
VEHICLE MEASUREMENT SHEET
Date
Test No
Vehicle Type
Identification
Sound Level
Measured
Allowed
Ambient
Lane
(Distance)
1 (nearest)
2
3
4 (farthest)
Sound Level Allowed
Heavy Truck
88
87
86
86
Medium Truck
86
85
84
84
Car
81
80
79
79
Motorcycle
81
80
77
79
27
Operator
-------
APPLICABLE NON-MOTOR VEHICLE REGULATIONS
(Sample Page)
Ordinance No. cont'd.
Sec. 16-139. NOISE DISTURBANCE PROHIBITED.
No person shall make, continue, or cause to be made
or continued, except as permitted, any noise disturbance
as defined in this subchapter, or any noise in excess of
the limits for such noise established in this subchapter.
Sec. 16-140. MAXIMUM PERMISSIBLE SOUND LEVELS BY
RECEIVING LAND USE: IMMEDIATE THREAT.
(a) Maximum Permissible Sound Levels. With the excep-
tion of sound levels elsewhere specifically authorized or
allowed in this subchapter, the following are the maximum
permissible sound levels allowed at or within the real
property boundary of a receiving land use:
(1) Table 1. SOUND LEVELS BY RECEIVING LAND USE
Zoning Category of
receiving land use Time Sound Level Limit, dBA
R-l to R-6 7 A.M. to 10 P.M. 60
Residential 10 P.M. to 7 A.M. 50
C-0, C-l to C-4, U-l
Commercial At all times 65
M-l to M-3
Industrial At all times 75
Noise Sensitive Area At all times 55
U-l Flood Plain or Use specific limit from
FW Floodway At all times above in view of char-
acter of land-use
28
Jffft
-------
STATIONARY NOISE MEASUREMENT DATA SHEET
Examiner:
Date:
.Time:
Address:
Noise Source:
Address:
Type of Receiving Property:
Complainant:
Residential D
Commercial D
Address:
Industrial Q
Sound Level Meter Manuf:_
Type:]
Serial II:
Calibrator Manuf:_
Type:
Serial //:"
Meter Check Batt. O Windscreen D
General Weather
«oTest Conditions Conditions
Test No.
Measurement Location
Ambient Noise
_Micro. Manuf:
Type:
Serial tf:"
A-Weighting
QFast Response Calibration Pretest dB
DSlow Poattest dB
Wind Velocity
Sketch of Site
(Indicate measuring locations, North direction, and appropriate distances).
-------
GLOSSARY OF TERMS
A-WEIGHTED SOUND LEVEL — the sound level observed on a standard level meter
when using the A-weighting network included in the circuitry.
A-WEIGHTING NETWORK — an electronic circuit in a sound level meter which
provides a frequency response in accordance with the standard characteristic
response called "A".
ABSORPTION — a property of materials or surfaces that reduces the amount that an
incident sound wave is reflected back into the air.
ACOUSTICS — the science of sound, including its production, it transmission, and the
effects of sound waves.
AMBIENT SOUND LEVEL — the noise associated with a given environment, exclusive
of a particular noise being tested, being usually a composite of sound from many
sources near and far, exclusive of intruding noises from isolated identifiable
sources.
ATTENUATION — the reduction or dissipation of sound energy resulting, for example,
from a silencing device or an increase of distance from the source.
AUDIO FREQUENCIES — the frequency of a sound wave that is within the normal
range of hearing, usually from 20 to 20,000 Hz (hertz or cycles per second).
BROADBAND NOISE — noise with energy content over a wide range of frequencies,
usually with no predominant tonal characteristics. (Air hoses and waterfalls are
examples.)
CALIBRATOR (ACOUSTICAL) — a device for producing a known sound pressure on the
microphone of a sound level measurement system.
DECIBEL — the unit of sound pressure level or sound level; the symbol is "dB".
30
JFA
-------
DYNAMIC CHARACTERISTIC (SOUND LEVEL METER) — a standard response speed
of the indicator (meter needle) on a sound level meter; "fast" and "slow" are
usually included on a sound level meter.
FAR FIELD — the sound field at a sufficient distance from a source so that the sound
pressure level obeys the inverse-square law; usually, the distance is about twice
the major dimension of the source or more.
FREE FIELD — a sound field in which sound is free to propagate without the effects of
obstacles, reflecting surfaces, and boundaries.
FREQUENCY — the number of times a second that a sound wave, usually a pure tone,
repeats itself; the basic unit was formerly caUed "cycle per second" or "cps" but
is now called "hertz", for which the symbol is "Hz".
FREQUENCY RESPONSE — the output signal or level of an instrument or circuit
resulting from an input signal of constant level and varying frequency.
HARD SITE — a sound measurement location at which the ground surface within a
specified measurement area is primarily hard-surfaced or reflective.
INVERSE-SQUARE LAW — a description of acoustic wave behavior in which the mean-
square pressure varies inversely with the square of the distance from the source;
this behavior usually occurs in free-field situations, so that the sound pressure
level decreases 6 dB with each doubling of distance from the source.
MICROPHONE — an electroacoustic transducer; a device that responds to sound
pressures and produces an electrical signal.
NEAR FIELD — the sound field very close to a source, where the sound pressure does
not obey the inverse-square law; see "far field".
NOISE — an undesirable or unwanted sound.
31
JFA
-------
NOISE LEVEL — a term sometimes used for "sound level" when the implication of
"noise" is intended.
NORMAL INCIDENCE — a condition in a sound field where the direction of sound
waves impinging on a microphone or surface is at right angles (normal) to the
microphone diaphragm or the surface.
PLANE WAVE — a sound wave where the wave fronts are parallel and at right angles
(normal, or perpendicular) to the direction of wave travel.
POINT SOURCE — a simple sound source that radiates sound energy uniformly in all
direction; also, a sound source that is small in relation to the wave length of the
sound or to the measurement distance.
PURE TONE — a sound wave whose waveform is a simple sine wave, or a sound
sensation characterized by a single pitch.
RANDOM INCIDENCE — a condition in a sound field where the direction of sound
waves impinging at a given point is random.
REFLECTION — a property of materials or surfaces that makes the material or
surface impervious to sound waves, so that the sound energy of an incident wave
is returned to the air; see "absorption".
REFRACTION — a bending of the direction of travel of sound wave from its
established path, caused, for example, by wind, a barrier, or a temperature
gradient.
REVERBERANT FIELD — a sound field in which sound is significantly affected by
obstacles, reflecting surfaces, and boundaries, and thus in which sound is
characterized by multiple echoes; the opposite of "free field".
REVERBERATION — the persistence of sound in an enclosed space, resulting from
multiple echoes or reflections.
ROOT-MEAN-SQUARE (RMS) — a term describing the mathematical process to
determine an "average" value of a complex signal.
32
-------
SOFT-SITE — a sound measurement location at which the ground surface within a
specified measurement area is primarily absorptive, such as grass.
SOUND — an oscillatory fluctuation of pressure in air; the auditory sensation caused
by such a fluctuation.
SOUND LEVEL — a weighted sound pressure level, determined by using a standard
sound level meter with a specified weighting network included in the circuitry;
usually, the use of the A-weighting network is implied if no other weighting is
noted.
SOUND LEVEL MEASUREMENT SYSTEM — any instrument or group of instruments
that provides an indication of the sound level occurring at the input transducer.
SOUND LEVEL METER — an instrument comprised of a microphone, amplifier,
weighting network, and output meter that is used for the measurement of sound;
the performance of a sound level meter is in accordance with the requirements
of the American National Standard Specification for Sound Level Meters, S1.4-
1971.
SOUND PRESSURE — the oscillatory fluctuations in atmospheric pressure that are
caused by the passage of a sound wave.
SOUND PRESSURE LEVEL — 20 times the logarithm of the ratio of the root-mean-
square value of a sound pressure to a reference sound pressure (20 micropascals)
in decibels (dB).
SPECTRUM — a description of the frequency content of a sound; a range of frequency
components with some common characteristic, such as "fan noise spectrum".
SPEED OF SOUND — the rate at which a sound wave travels; in air, it is 1127 ft/sec
(344 m/sec) at an air temperature of 68°F (20°C).
SPHERICAL DIVERGENCE — propagation of spherical waves such that the intensity
of the wave obeys the inverse-square law.
33
-------
SPHERICAL WAVE — a sound wave where the wave fronts are concentric spherical
surfaces, such as from a point source in a free field.
WAVE FRONT — an imaginary surface of a sound wave as it travels through the
atmosphere.
WAVELENGTH — for a periodic wave (such as sound in air), the distance between
identical location on two successive waves; it is inversely proportional to the
frequency of the waves.
WINDSCREEN — a porous device to cover the microphone of a sound level measure-
ment system, intended to minimize the effects of winds and wind gusts on the
sound levels being measured; typically made of reticulated (open cell)
polyurethane foam and spherical in shape.
34
-------
SOUND LEVELS OF TYPICAL NOISE SOURCES
MO dB(A)
Threshold of pain
130
•10
•0 Threshold of hearing
35
JBX
-------
SOUND LEVEL AS A FUNCTION OF DISTANCE FOR A SMALL SOURCE
Distance
Increase
Factors
1
1 1/2
2
2 1/2
3
3 1/2
4
4 1/2
5
5 1/2
6
6 1/2
7
7 1/2
8
Sound
Level
Decrease
0.0
- 3.5
- 6.0
- 8.0
- 9.5
- 10.9
- 12.0
- 13
- 14
- 14.8
- 15.6
- 16.3
-16.9
- 17.5
- 18
Distance
Decrease
Factor
1
2/3
1/2
2/5
1/3
2/7
1/4
2/9
1/5
2/11
1/6
2/13
1/7
2/15
1/8
Sound
Level
Increase
0
+ 3.5
+ 6.0
+ 8.0
+ 9.5
+ 10.9
+ 12.0
+ 13.0
+ 14.0
+ 14.8
+ 15.6
+ 16.3
+ 16.9
+ 17.5
+ 18
Example:
At 50 feet the sound level is 87 dBA.
What is the sound level at 100 feet? The distance increase factor from 50 feet is
2, so 87 - 6 = 81 dBA.
What is the sound level at 300 feet? The distance increase factor from 50 feet is
6, so 87 - 15.6 = 71.4 dBA.
What is the sound level at 20 feet? The distance decrease factor from 50 feet is
2/5 so 87 + 8 = 95 dBA.
What is the sound level at 25 feet? The distance decrease factor from 50 feet is
1/2, so 87 + 6 = 93 dBA. 36
JFA
-------
ADDITION AND SUBTRACTION OF SOUND LEVELS
Addition
When one wishes to add two sound levels, one uses a table of values, because decibels
are logarithmic quantities and cannot be added according to the rules of ordinary
arithmetic. To add two sound levels A and B, proceed as follows:
(1) Subtract the smaller level from the larger, A - B
(2) Use this difference in the table below, and read off the addition term, T.
(3) Add the addition term to the larger sound level, A + T.
This value, A + T, will be the sound level which results from adding the two levels, A
and B.
For example, suppose two chain saws which produce sound levels of 86 dB(A) and 83
dB(A) at 100 feet are brought together. Their combined level can be calculated by (1)
subtracting 83 from 86 to get 3, (2) entering the table with 3 to find the addition term,
1.5, and (3) adding 1.5 to 86 to yield 87.5 dB(A), the sound level at 100 feet of the two
chain saws operating together.
When more than two levels must be combined, add them one at a time, starting with the
smallest. Thus, A + B + C + Dis done A + B, then (A + B) + C, and finally (A + B) + C
+ D. (See example (d) below.)
Other examples:
(a) What is the combined level from two sources, each of 85 dB? The difference
is zero so the addition term is 3, and the combined level is 85 + 3 = 88 dB.
(b) What is the combined level of an ambient of 75dB and a source with a level
of 80 dB? The difference is 5, the addition term is 1, and the combined level is 80 + 1 =
81 dB.
37
JEV
-------
(c) What is the combined level of two sources with levels of 70 dB and 80 dB?
The difference is 10, the addition term is zero, and the combined level is 80 + 0 = 80 dB.
(This is the calculation behind the rule that measurements should be made when the
ambient noise level is 10 dB less than the noise limit; the ambient then will not
contribute to the overall sound level.)
(d) What is the combined level of three sources with levels of 68 dB, 71 dB, and
72 dB? The difference between the first two levels is 71 - 68 = 3 and the addition term
is 1.5, so the combined level of the first two sources is 71 + 1.5 = 72.5 dB. The
difference between this level and the third level is 72.5 - 72 = 0.5, and the addition
term is 3, so the combined level of all three sources is 72.5 + 3 = 75.5 dB.
Difference Between the Sound
Level of the Two Sources
Equal to or
greater than,
0
1
2
3
4
5
6
7
8
9
10
but less
than
1
2
3
4
5
6
7
8
9
10
-
Addition Term, T
(add to the
larger level)
(Values are
approximations)
3
2.5
2
1.5
1.5
1
1
0.5
0.5
0.5
0
Table for Addition of Sound Levels
38
JIA
-------
Subtraction
Sound levels are subtracted by using a similar table that is given below. To subtract
one sound level B from another sound level A, proceed as follows:
(1) Subtract the smaller from the larger, A - B.
(2) Use the difference in the table below, and read off the subtraction term,
S.
(3) Subtract the subtraction term from the larger sound level, A - S.
The value A - S will be the sound level which results from subtracting sound level B
from sound level A.
In practice, the larger level is always the combined level of two or more sources of the
same or different kinds.
For example, if one has two snowmobiles which produce a combined level of 92 dB at
100 feet, and one of them is known to produce a level of 88 dB by itself at that
distance, what will the level of the other one be alone? Subtracting 88 from 92 leaves 4
and the table shows that the subtraction term is 2. The larger value, 92 dB, minus the
subtraction term leaves 90 dB. Thus 90 dB is the sound level at 100 feet from the
second snowmobile.
As another example, suppose the ambient noise level is 75 dB before an air compressor
is turned on, and that the sound level is 81 dB after it is turned on. What is the noise
level of the air compressor? 81 - 75 = 6. The table shows that the subtraction term is
1. 81 - 1 = 80 dB, which is the noise level of the air compressor.
Other examples:
(a) What is the level that results when a source with a level of 80 dB is removed
from a combined level of 85 dB? The difference is 5, the subtraction term is 1.5, so the
resulting level is 85 - 1.5 = 83.5 dB.
(b) What is the level that results when a source with a level of 81 dB is removed
from a combined level of 90 dB? The difference is 9, the subtraction term is 0.5, so the
resulting level is 90 - 0.5 = 89.5 dB. Q
JBX
-------
Difference between the Sound
Level of the Combined Sources
and the Level of One Source
Equal to or
greater than,
0
1
2
3
4
5
6
7
8
9
10
11
but less
than
1
2
3
4
5
6
7
8
9
10
11
-
Subtraction Term, S
(subtract from the
combined level)
(Values are
approximations)
more than 6*
between 6 and 5*
between 4 and 3*
3
2
1.5
1
1
0.5
0.5
0.5
0
Table for Subtraction of Sound Levels
*
Because of the uncertainties in the levels which are calculated from using these
subtraction terms, law enforcement based on sound level differences of less than 3 dB
may be unwise.
40
JfA
-------
OPERATION OF THE GENRAD TYPE 1565-B
SOUND LEVEL METER
1. Check that the microphone is firmly screwed on and remove protective dust
cover.
2. Slide "ON" switch to the right and depress "BAT CHECK" button.
3. Check that the pointer lies within the area to the right of the "BAT" mark on the
meter scale. If it does not, do not use the meter until the batteries have been
replaced and the battery check is satisfactory.
4. Calibrate the meter as follows:
a. Set the RANGE SWITCH to read between 110 and 120 dB.
b. Depress the "A" button.
c. Allow about 20-30 seconds for the circuits to charge up.
d. Place the microphone into the coupler of the calibrator
(GenRad Type 1567).
e. Slide the switch on the calibrator on "ON".
f. Adjust the meter to read 114 dBA + 0.3 dB by turning a small screwdriver
in the sensitivity adjustment slot on the face of the meter.
If the battery indicator on the bottom of the calibrator does not indicate "OK"
(yellow zone), the calibrator battery must be replaced.
5. Sound Level Measurements.
a. Set "RANGE SWITCH" to a high value to avoid overloading the meter
when switching on.
b. The meter response should be set to "FAST". This occurs with the "SLOW"
button in the out position. ("SLOW" response is achieved with the "SLOW"
button depressed).
c. Orient the meter so that a direct line from the noise source to the meter
would be parallel with the flat surface of the microphone (grazing
incidence).
d. The sound level is then the meter scale reading.
41
JB\
-------
SAMPLE COURTROOM TESTIMONY NOTES
Questions from Prosecutor and Testimony
of Noise Enforcement Officer
1. Noise Control Officer called to the stand.
2. State name and occupation: Susan Redford,
Police Officer.
Were you so employed on the date of July 31,
1978? Yes.
Where were you working on or about 6:00 p.m.
on that date? At the site we call "A" located
on Hamilton Street between 14th and 15th
Avenues.
Is that in the City of Allentown? Yes.
3. Establish a competent witness:
What training, instruction, or experience have
you had that qualifies you to use noise moni-
toring equipment? I have had 16 hours of formal
training in the operation of sound level meters
and the measurement of motor vehicle and
stationary noise and I have in my possession a
certificate attesting to that fact.
4. Serving in that capacity, what did you do? j[
issued a summons to John Bersford Tipton,
operator of a 1972 Brown Rambler American.
5. Can you now identify the person to whom you
issued the summons? Yes.
6. Is he in the court? Yes. Please point out the
individual to the court. (Point out.)
7. In your own words, describe the events of that
date leading to the issuance of said summons.
I was on routine noise monitoring duty that
evening observing traffic northbound on Hamil-
ton Street in the 1400 block.
I had issued two summonses prior to the one in
question. I was using equipment manufactured
by GenRad which meets the requirements of
Regulation Title 67, Chapter 450.
42
-------
The equipment was set up using the criteria
established in the ordinance (enter into evi-
dence). This establishes the basis for technical
accuracy in monitoring with our equipment.
The microphone location was at a distance of 50
feet from the center-line of travel. Wind was less
than 2 mph as measured before and after test. A
windscreen was used and I held the sound level
meter in accordance with the manufacturer's
instructions. I could see that the sound level
meter indication was determined when the vehi-
cle was in the measurement area and that the
vehicle was responsible for the meter indication
observed.
8. What type of calibration is performed on this
equipment to ensure its accuracy?
Two types:
Field Calibration; (Described on procedure
sheet)
This procedure is performed on set-up and shut-
down only of the monitoring equipment that is
used. A known and calibrated sound source is
used to produce a known sound level at the
microphone, permitting the system to be
adjusted to display the known sound level
reference. This verifies that the system is
recording the sound level accurately.
System Calibration;
This is a calibration procedure which is
performed by a certifying laboratory. The
equipment is calibrated by the factory using
ANSI methodology against standards traceable to
those at the National Bureau of Standards.
Accuracy and proper operation of the equipment
are certified at these lab facilities. Our equip-
ment is calibrated in this manner every 180 days.
(Enter calibration certification into evidence).
9. Was the equipment in field calibration and was
the system calibration in effect and current on
the date of issuance of the summons in question?
Yes.
43
JFA
-------
10. In your observation of the vehicle in violation,
did you note the presence of any other noisy
vehicles at that time? None. And there was a 6
dB swing between the vehicle in question and the
proceeding and succeeding automobiles. This
permits our meter to respond to the level of the
vehicle under observation.
11. What was the ambient level observed at that
time? 52 dBA.
12. Is this level at least 10 dB under your enforce-
ment
Note: This is dependent upon requirements
specified in regulation or enforcement test
procedure.
13. What affect, if any, would the observed ambient
level have on your reading of the vehicle in
violation? An ambient of 10 dB under the
maximum permitted ordinance level would con-
tribute less than .5 dB to the reading if the
vehicle emitted noise at the maximum permis-
sible level. More than 10 dB down would
contribute even less; and would be functionally
negligible in the final reading.
14. Did you note any other noise sources that could
have caused an erroneous reading on the vehicle
in violation? None.
15 Were there any reflecting surfaces near your
monitoring location that would induce an error in
your reading? None.
16. According to the monitoring procedure estab-
lished in Pennsylvania State Regulation Title 67,
Chapter 450, for collection of evidence of a
vehicular noise violation, is your observation of
this vehicle an accurate one? Yes.
17. What was the allowable speed limit on Hamilton
Street at your measuring location? The speed
limit was 25 mph.
18. Describe the site. The measuring site which we
have approved for measurements is called Site
"A". It meets the requirements for a soft site as
per Parts 1 and 3 of the State Regulation.
44
A
JBV
-------
19. What was the reading observed on the vehicle in
question? 86 dBA.
20. Is that in violation of the Pennsylvania state
noise regulation levels for vehicles of this class?
Yes.
21. By how many decibels? 4 decibels.
22. Are there any other conditions of the collection
of this evidence that should be noted? No.
23. After observing the excessive reading, did you
issue a summons to the driver of the vehicle in
question? Yes.
24. What did you observe? The vehicle was not
equipped with a muffler in its exhaust system.
25. On visual confirmation of the equipment of this
vehicle's exhaust system, is there any doubt in
your mind that this vehicle was the source of the
noise observed in violation? None.
Note: It may be desirable to show the judge
the equipment and its dynamic range to
illustrate the ease of interpretation of the
noise reading observed. (Especially in the
case of the digital capture on the GenRad
198lf if used). If you have equipment dif-
ficult to interpret or read, this is not a
good idea.
45
-------
WORKSHOP
ON
POLICE ENFORCEMENT OF NOISE REGULATIONS
Evaluation Sheet
Date of Workshop:
We are very interested in your opinions on the content, conduct, and usefulness of
this course. To help us improve future courses, please fill in the information below.
Your Job Description or Title: __ _ _ - _
Please rate each of the items below by CIRCLING the appropriate number.
Stated goals of the course:
Not Achieved: 1234567; Exceeded
Your personal expectations for the course:
Not Achieved; 1234567; Exceeded
Your personal involvement in the course process:
Shallow; 1234567; Deep
Relevance of program eonte^to^ur work^ ^^^
Complexity of the course mate^al:^ ^^^^ Too Complicated
Course content: ^f ficient Theory; 1234567; Too Much Theory
Program format: j 2 3 4 5 6 7; Excellent
Audio/visual aids: GeneraUy Unhelpful; 1234567; Generally Very
Helpful
Arrangements (i.e., cater i
Instructors' shared knowledge of subject:
Poor; 1234567; Excellent
46
.__
JFA
-------
Instructors' teaching techniques:
Ineffective; 1234567; Highly Effective
Overall, I would rate this workshop:
Poor; 1234567; Excellent
By taking this course, do you think you now have an adequate understanding of:
YES NO
1. The principles of sound and noise?
2. How to operate noise measurement equipment?
3. Noise measurement techniques?
4. Types of complaints that may arise?
5. Legal aspects of noise enforcement?
6. How to enforce motor vehicle noise regulations?
7. How to enforce stationary noise regulations?
8. If you asked specific questions, were they
answered satisfactorily?
If we had a chance to hold this course again, what changes would you recommend to
improve it?
I would not make any changes ( ).
I would change:
47
JJA
-------
WORKSHOP ON POLICE ENFORCEMENT
OF NOISE REGULATIONS
Name
Date "
EXAM — PART I
Time Allowed, 15 minutes, "Open Book"
1. Define "noise"
2. Circle the one characteristic that does not relate to sound: Intensity, frequency,
loudness, force pressure, duration
3. We describe "sound pressure level" by 1) decibels ( ), 2) hertz ( ).
4. The sound level of an automobile, when measured at 50 feet, is approximately 10
( ), 40 ( ), 70 ( ), 100 ( ), or 120 ( ) dBA.
5. A pure tone is
a) a sound at a single frequency
b) a measure of hearing
c) a sound level
d) a measuring instrument
6. Match types of noises by drawing lines from source to type of noise.
a) steady electric fan
b) impulse electric razor
c) slowly fluctuating aircraft passing
hammer
7. What frequency weighting scale is most widely used for community noise? A, B,
C, FLAT
8. Why is it used?
a) Measures more accurately
b) It is easier to use
c) It approximates human hearing
d) None of the above
9. If we measure something using the A-scale, we say the sound level is:
X dBA ( ), X decibels ( ), X hertz ( )
10. Which components are not a part of most sound level meters?
a) Weighting switch
b) Amplifier
c) Windgauge
d) Acoustical Calibrator
e) Meter response switch
48
JFA
-------
11. Combine sound levels of 50 dB and 50 dB
Approximate Answer: 100 dB, 25 dB, 75 dB, 53 dB
12. Subtract a sound level of 80 dB from a combined level of 100 dB:
Approximate Answer: 100 dB, 20 dB, 53 dB
13. What characteristics effect sound reduction?
a) distance
b) barriers
c) source type
d) all of the above
14. Can you cite violators of the motor vehicle noise limit based on measurements
made on private streets.? Yes No
15. If you measure noise in rain, the measurement is
a) invalid
b) valid
49
JBX
-------
WORKSHOP ON POLICE ENFORCEMENT
OF NOISE REGULATIONS
(Specifically prepared for Pennsylvania)
Name
Date
Exam — PART H
Time allowed, 15 minutes, "Open Book"
16. What don't the Penn DOT Noise Regulations apply to:
a) Snowmobiles
b) Fire equipment
c) Ambulances
d) Four-wheel drive vehicles
17. Would hard packed dirt be considered a "soft site?" Yes , No
18. Give an example of the type of vehicle for which the reference point would not
be the front of the vehicle.
a) Motorcycle
b) Station wagon
c) "Greyhound" bus
d) Semi-tractor
e) All of the above
19. What is the maximum noise limit at 50 feet allowed for a Rambler American
when measured in a 50-mph speed zone and on a soft site? 76, 78, 82, 86, 88
20. Motor vehicle noise limits apply to (check those that apply)
a) Motorscooters
b) Busses
c) Riding mowers
d) Garbage trucks while compacting
e) Garbage trucks while moving
21. What is the "maximum" measurement tolerance allowed? 0.3 dB, 1 dB, 2 dB,
10 dBA, 1000 Hz.
22. Can an officer cite a driver for "tire peeling?" Yes , No
23. Is there anything stopping you from measuring noise after a stop sign or toll
booth?
a) Yes, if there are reflecting surfaces near by or there are a lot of vehicles
in the measuring area.
b) No, if the toll booths are in a clear zone and the measurements are
performed according to the regulations.
c) All of the above.
50
JB\
-------
24. Can you use a Type I meter for motor vehicle noise measurements?
Yes , No
25. Do you have to calibrate it before every vehicle measurement?
a) Yes
b) No, but if you have the time, it can't hurt
26. Should you use the windscreen if the steady wind is under 12 miles per hour?
a) Yes
b) No - the measurements are not valid
27. Can there be snow on the ground when you measure — if the lane of travel is
dry? Yes , No
28. How much lower than the noise limit must the ambient noise level be?
a) 2 dB
b) 6 dB
c) 10 dB
29. You use A-weighted filter and fast response. True , False
30. If you measure closer than 50 feet, the allowable limit will be
a) Greater than that at 50 feet
b) Less than that at 50 feet
c) The same as that at 50 feet
51
-------
gllentoton police
&Uentoton,
Certify
cri
K)
gattfifactorilp completeb a training course in
NOISE MEASUREMENT AND ENFORCEMENT
ftp tlje Bureau of police, &Uentoton,
at tfje ^IHentoton police
Bate.
DIRBtTOR—SERVICES AND TRAINING
CHIEF OF POLICE
------- |