1 STUDY OF SCUD NISTE
COLLECTION SYSTEMS
WITH MOL1I-MUI CREWS
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This report has been reproduced as received from
the contractor. No editorial or other changes have
been made, although a new title page and foreword
have been added.
Since technological innovation in refuse disposal
has been relatively sparse, and since the entire
concept of solid waste management is quite new,
--the conclusions and evaluations presented should
be considered as preliminary in nature.
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A STUDY OF SOLID WASTE COLLECTION SYSTEMS
COMPARING ONE-MAN WITH MULTI-MAN CREWS
Final Report
This report (SW-9c) was written for
the Bureau of Solid Waste Management
by Ralph Stone and Company,. Inc. , Engineers
^ Los Angeles, California
under Contract No. PH 86-67-248
U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Consumer Protection and Environmental Health Service
Environmental Control Administration
Bureau of Solid Waste Management
1969
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PUBLIC HEALTH SERVICE PUBLICATION NO. 1892
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 - Price $2.25
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FOREWORD
An estimated 800 million pounds of solid wastes of all types
are generated in the United States every day. The cost for handling
and disposing of this vast quantity of waste materials is also very
large. A recent study indicates that Americans spend $4. 5 billion
annually for solid waste management, and that even this sum is
inadequate to insure against environmental pollution from solid
waste sources.
Approximately 75 percent of the cost of solid waste management
is attributable to the collection process, and the present study of a
one-man collection system -was funded by the Bureau of Solid Waste
Management under Contract No. PH 86-67-248, for the purpose of
examining one means for reducing collection costs and improving
the level of community sanitation services.
--RICHARD D. VAUGHAN, Director
Bureau of Solid Waste Management
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PREFACE
Recently, collection systems have been reported for curbside
collection of residential refuse in Southern California and other
areas wherein one man acts as both driver and loader. These syterns
normally utilize right-hand drive, side-loading packer vehicles.
Reports indicated that substantial reductions in the overall costs
of providing collection service were possible using this new system.
It was not known whether the apparent savings were due to the smaller
crew size or to a combination of equipment, collection methodology,
routing characteristics, haul distances, and personnel. Accordingly,
the Solid Wastes Program, United States Public Health Service,
authorized Ralph Stone and Company, Inc., Engineers, to study and
report on one-man refuse collection operations. Ralph Stone was the
Project Director, with able support of Robert P. Stearns, Project
Engineer. Anthony Svane, Harjeet Singh, Helen Friedland, and other
staff personnel provided technical assistance.
The prime purpose of the study was to define the nature of the
possible savings, if any, due to a one-man crew; to compare the
efficiency of the one-man crew with two- and three-man crews; and to
project the future use of the one-man system for refuse collection.
In addition, a catalog of the equipment available for one-man
operation was compiled.
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ACKNOWLEDGMENTS
We wish to express our appreciation to
representatives from the Public Health Service's solid wastes program
for their encouragement, guidance, and assistance in the conduct of
this study. In particular, we wish to thank Mr. John Kennedy,
Project Officer, for his assistance which has aided immeasurably
in the compilation, interpretation, and presentation of the information
within this report.
We would also like to take this opportunity to express thanks
to the many engineers and administrators of cities, private refuse
collection firms, and refuse equipment manufacturers who also
participated in this study. Numerous cities and private collection
firms have supplied complex background information necessary for
this study, including information on ordinances, costs, tonnages
collected, and other relevant facts.
Many manufacturers of refuse collection equipment were equally
helpful; they supplied us with brochures describing available equipment
and responded to our specific questions. Additionally, we received
information from many public cleansing authorities in Europe.
Summary refuse collection data presented within this report
would not have been possible without the generous assistance of
over two hundred cities located throughout the nation. Detailed
summary information of their refuse collection operations, ordinances
governing refuse collection, man-hours, tonnage collected, costs,
injury rates, and other relevant data is presented in the report.
The excellent cooperation received illustrates the current high
level of interest on the part of public and private agencies in
refuse collection operations.
--EALPH STONE
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TABLE OF CONTENTS
FOREWORD
PREFACE v
ACKNOWLEDGMENTS vi
TABLE OF CONTENTS vil
ABSTRACT xix
CONCLUSIONS xxi
RECOMMENDATIONS xxv
SUMMARY xxvii
I. INTRODUCTION AND PURPOSE 1
II. DETAILED APPROACH 2
A. Field Surveys and Analysis 3
1. General 3
2. Field Study Program 4
3. Results - Field Surveys 12
B. National Survey of Collection Practice 44
1. Public vs Private Collection Service 49
2. Type of Equipment 49
3. Capacity of Equipment 49
4. Crew Size 52
5. Pick-up Location 52
6. Frequency of Collection 52
7. Lost Time Accidents 59
8. Collection Costs 59
C. Time and Motion Analysis 63
1. General 63
2. Analysis - Time and Motion 63
3. Results - Time and Motion Analysis 67
a. Curbside Collection 67
b. Backyard Collection 67
c. Refuse Set-out Procedures 75
d. Alley Collection 75
e. Modified Curbside Collection 77
4. Special Analysis 80
a. Fatigue 80
b. Delays 91
VII
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TABLE OF CONTENTS - CONTINUED
Page
D. Mathematical Model 95
1. General 95
2. Basic Assumptions 99
3. Symbols 100
4. Formulation 103
5. Results - Mathematical Model 104
6. Nomographs 131
E. Equipment 145
1. General 145
2. Equipment Characteristics 145
3. European Equipment 147
GLOSSARY 150
BIBLIOGRAPHY 153
APPENDICES 159
ATTACHMENTS
viii
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LIST OF TABLES
Page
I Summary of Collection Practices - Selected Cities
and Private Firms 6
II Summary of Collection Practices - Supplemental
Cities and Private Firms 7
III Field Survey Summary Data - Detailed Surveys 13
IV Route Man-Minutes per Ton 14
V Field Survey Summary Data - Abbreviated Surveys 15
VI Number of Cities in Each State Supplying Collection
Data 46
VII Population Represented by 234 Cities Responding to
Data Survey 47
VIII Type of Collection Services Reported by Responding
Cities 47
IX Equipment According to Type 50
X Average Capacity of Equipment Compared with Size of
City for Once a Week and Twice a Week Collection 51
XI Normal Crew Size or Sizes 53
XII Crew Size According to Type of Equipment 54
XIII Total Number of Units of Equipment According to Type
of Equipment and Crew Size 55
XIV Crew Size by Location of Pickup 56
XV Collection Location 57
XVI Frequency of Collection Service by Size of City 58
XVII Number of Lost Time Accidents 60
XVIII Annual Solid Waste Tonnage and Collection Costs 61
XIX Average Annual Cost per Ton Combined Averages 61
XX Time Standards - Alley, Backyard, and Modified
Curbside Refuse Collection 76
IX
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LIST OF TABLES - CONTINUED
Pace
XXI Human Factors Experiment: Physical Data - Subjects 86
XXII Human Factors Experiment : Summary of Results -
Pilot Study 89
XXIII Delays - Municipality A, Municipality B, Municipality C 92
XXIV Costs of Vehicle Time - Equipment Cost Only 101
XXV Example Table - Nomographs 144
x
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LIST OF FIGURES
Page
1 Distribution - Cans at the Collection Stop 17
2 Distribution - Items at Collection Stop 18
3 Distribution - Collection Time: One Can 19
4 Distribution - Collection Time: Two Cans 20
5 Distribution - Collection Time: Three Cans 21
6 Distribution - Collection Time: Four Cans 22
7 Distribution - Collection Time: Five Cans 23
8 Distribution - Collection Time per Stop 24
9 Field Survey - Average Collection Time Per Stop 25
10 Field Survey - Average Collection Time: Disposables
Only 26
11 Distribution - Travel Time Between Collection Stops 27
12 Distribution - Cans at Collection Stop 29
13 Distribution - Items at Collection Stop 30
14 Distribution - Collection Time per Stop 31
15 Average Collection Time 32
16 Distribution - Cans at Collection Stop 33
17 Distribution - Items per Collection Stop 34
18 Distribution - Collection Time per Stop 35
19 Average Collection Time per Stop 35
20 Distribution - Collection Time per Stop 37
21 Distribution - Collection Time per Stop 38
22 Distribution - Collection Time per Stop 39
23 Average Collection Time per Stop 40
XI
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LIST OF FIGURES - CONTINUED
24
25
26
27
28
29
Average Collection Time per Stop
Average Collection Time per Stop
Collection Time - Cans and Disposables
Cities Represented in Solid Waste Survey
Cost of Refuse Collection in 46 Cities
Standard Collection Time - Cans: Curbside
Page
41
42
43
48
62
Collection 68
30 Standard Collection Time - Disposables: Curbside
Collection 69
31 Equipment Factors - Standard Collection Time:
Curbside Collection 70
32 Schematic: Two-Man Backyard Refuse Collection 72
33 Schematic: Three-Man Backyard Refuse Collection 73
34 Schematic: One-Man Alley Refuse Collection 78
35 Schematic: Two-Man Alley Refuse Collection 79
36 Fatigue Analysis - Average Collection Time per Stop 81
37 Fatigue Analysis - Average Collection Time per Stop 82
38 Fatigue Analysis - Average Collection Time per Stop 83
39 Human Factors Experimental Data 90
40 Comparison - Average Collection Time: Field -
Adjusted Standard 96
41 Comparison - Average Collection Time: Field -
Adjusted Standard 97
42 Comparison - Average Collection Time: Field -
Adjusted Standard 98
43 Total Cost Curves - Crew Comparison 105
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LIST OF FIGURES - CONTINUED
44 Total Cost Curves - Crew Comparison 106
45 Total Cost Curves - Crew Comparison 107
46 Total Cost Curve - Range: One-Man Crew 109
47 Total Cost Curves - Range: Two-Man Crew 110
48 Total Cost Curve - Range: Three-Man Crew 111
49 Average Services Collected per Crew - Crew Comparison 112
50 Average Services Collected per Crew - Crew Comparison 113
51 Average Services Collected per Crew - Crew Comparison 114
52 Range in Services Collected per Crew: One-Man Crew 115
53 Range in Services Collected per Crew: Two-Man Crew 116
54 Range in Services Collected per Crew: Three-Man Crew 117
55 Cost per Service - Crew Comparison 118
56 Cost per Service - Crew Comparison 119
57 Cost per Service - Crew Comparison 120
58 Average Services Collected per Crew: One-Man Crew 121
59 Average Services Collected per Crew: Two-Man Crew 122
60 Average Services Collected per Crew: Three-Man Crew 123
61 Total Cost per Ton - Backyard Collection 125
62 Services Collected - Backyard Collection 126
63 Total Cost per Ton - Alley Collection 127
64 Services Collected - Alley Collection 128
65 Total Cost per Ton - Modified Curbside Collection -
Shoulder Barrel - Method A 129
66 Average Services Collected per Crew - Modified
Curbside Collection - Shoulder Barrel - Method A 130
Xlll
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LIST OF FIGURES - CONTINUED
67 Cost per Ton - Backyard Set-Out with Curbside
Collection 132
68 Total Cost Curves - Crew Comparison 133
69 Total Cost Curves - Crew Comparison 134
70 Average Services Collected per Crew - Crew Comparison 135
71 Average Services Collected per Crew - Crew Comparison 136
72 Cost per Service - Crew Comparison 137
73 Cost per Service - Crew Comparison 138
74 Nomograph Number 1 - System Design 139
75 Nomograph Number 2 - System Design 140
xiv
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LIST OF PHOTOGRAPHS
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
XIII
XIV
XV
A.
B.
C.
D.
E.
F.
G.
Field Survey Timing Board
Equipment - Municipality B
Equipment - Municipality C
Equipment - Municipality A
TRAC - Driving
TRAC - Loading
Collector Loading Two Cans Simultaneously
Video Tape Monitoring Equipment
View from Video Monitor
Experiment in Progress
Data Recording
Dustless Collection System - Vienna, Austria
Screw Compactor - Athens, Greece
Screw Compactor - Central Europe
Compaction Vehicle - Nevi, France
APPENDICES
Field Survey Data Form
Field Survey Data Summary Form
Economic Calculation - Disposable Containers
National Survey Data Form
Human Factors Data Form
Video TV Use for Human Factors Studies
Equipment Specifications
Page
11
11
11
11
45
45
65
85
85
85
85
148
148
149
149
159
161
164
167
169
170
172
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ABSTRACT
This report summarizes research into the relative functional
and cost efficiencies of the one-man crew when compared to alternative
two- or three-man crews for the collection of refuse.
Four basic analytical techniques were used: comprehensive
field surveys; nationwide survey data analysis; time-motion studies;
and a mathematical model.
The comprehensive field surveys were applied to four municipal
collection systems and two private-firm collection systems. They
were supplemented by abbreviated field surveys in selected cities
throughout the United States. The comprehensive surveys analyzed
four one-man crews, one two-man crew, and one three-man crew. Care
was taken to eliminate extraneous factors not related to crew-size
efficiencies which might influence the data and distort the results.
Detailed observations and records were made of significant measurable
factors relating to equipment, containers, productive and nonproductive
time, man-hours, and collection techniques. Movie film and video
tape records, direct physical observations, and statistical analysis
were applied to evaluate relative efficiency based on crew size,
and to determine the influence of basic factors on that efficiency.
The time-motion studies compared field times in three cities
with Methods-Time-Measurement (or MTM) values developed under
controlled laboratory conditions. Preliminary analysis for fatigue
effects were examined in relationship to loading height and total
container weight; and standard collection times were developed for
varying collection locations, techniques, and equipment.
A mathematical model was designed to permit simulation of the
refuse collection system. The model is a formula which expresses
the interrelationships among the variables affecting collection
time and system cost. Nomographs were developed which can be used
to project the possible effects of varying truck volumes, refuse
quantities, densities, times, crew-sizes, and route sizes.
Tables and charts have been prepared to support and illustrate
the information developed, and the conclusions and recommendations
which have been based thereon.
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CONCLUSIONS
The following conclusions were based on the field studies and time
and motion analyses described in this report. The conditions, limitations,
and assumptions governing specific data and its analysis are defined in
the related sections of the text.
1. For curbside collection of refuse, one-man crews were more
efficient than multi-man crews; the productivity of the one-man crew
was greater than that of the multi-man crew when measured in terms of
route man-hours per ton.
2. The one-man crew was similarly more efficient than the multi-
man crew for alley collection of refuse.
3. Multi-man crews were more efficient for backyard carryout
collection of refuse.
4. Under specified assumptions for important route factors and
costs of equipment and labor, the unit cost of refuse collection by
the one-man crew was 25 to 45 percent less than the two-man crew and
35 to 50 percent less than the three-man crew.
5. Although multi-man crews required less equipment of equal size
than the one-man crews, this had a negligible effect on unit collection
costs when the combined equipment operating, amortization, and labor
costs were compared for one-man and multi-man collection.
6. In residential or light commercial curb or alley collection,
the work load was not excessive for one-man operation.
7- With existing collection equipment designs, side-loading
compactor vehicles were the most suitable type of one-man operated
equipment for curbside and alley refuse collection operations.
8. Significant savings in curbside collection time were achieved
by the use of disposable containers such as paper or plastic bags.
9. Industrial time standards developed for production control
and design were found applicable to evaluating the task of refuse
collection.
10. Based on preliminary human factors studies, the weight of the
refuse container and contents was more important in the rate of collec-
tion personnel performance degradation than vehicular loading height.
11. Various complex refuse collection system interrelations affect
optimum crew size, equipment, and cost benefits.
The following conclusions were based on the national survey data
described in this report.
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1. The predominate (1968) practice of refuse collection used by
a sample of 234 cities involved the use of rear-loading packer vehicles
with three-man crews for curb and/or alley collection.
2. Only a limited number of small cities used one-man crews for
refuse collection.
3. In a sample of 234 cities, unit operating costs for collection
of refuse generally increased with the size of the city.
The following conclusions are based on the study as a whole.
1. Public refuse collection systems in general have been slower
than private collection systems to adopt new refuse collection techno-
logy such as smaller crew sizes, certain low-cost or high-efficiency
equipment types, and related system modifications.
2. If labor costs and the incidence and severity of collection
labor strikes continue to increase, the one-man collection system may
become more common, particularly in private collection firms and in
smaller cities.
3. Current municipal collection systems are frequently character-
ized by: personnel with limited skills and work experience; high
absenteeism; absence of promotion opportunity; and lack of public
recognition of the collection worker's contribution.
4. As the cost-benefits associated with the one-man crew are
sensitive to excessive absenteeism and poor work habits, the one-man
collection system generally requires a higher level of responsibility,
performance, and loyalty on the part of both collection and supervisory
personnel.
5. Successful implementation of a one-man collection system will
probably require: higher personnel standards; higher salary rates;
potential upward mobility in the job structure; employees with a sense
of personal pride and responsibility; and engineering evaluation of
route structure and equipment requirements.
6. There is an immediate need for improvement in the design and
application of specific equipment for refuse collection tasks. The
combination of packer body and conventional truck chassis does not
provide for an optimum man-machine relationship.
7. Many existing collection systems can be significantly improved
by engineering design of collection methodology, including crew and
truck sizes.
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8. Increased awareness by collection system administrators
concerning potential cost savings and improved human factors can
lead to the demand for and use of better equipment designs.
9. Careful planning and engineering of the collection system can
realize maximum public health protection, cost savings, improved service
and reduction in the frequency of labor strikes and other personnel
difficulties.
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RECOMMENDATIONS
A. General
1. Collection managers should upgrade the quality of their
personnel to the caliber required for potential advancement to
positions as truck drivers, mechanical equipment operators, super-
visors, clerks, and other skilled jobs, following experience and
training programs.
2. Personnel policies in a municipal collection service, particular-
ly under Civil Service regulations, should encourage advancement in the
service or reassignment to other municipal departments as needed.
3. Private firms and municipalities initiating a refuse collection
system incorporating curbside or alley collection should weigh the
possible advantages of the one-man crew.
4. Existing private and municipal operations should review the
possibility of reducing crew sizes if multi-man crews are presently
performing curbside and/or alley collections.
5. Municipalities and private collection operations should estab-
lish work and time standards for their collection crews, and periodic
checks to determine compliance should be instituted.
6. When equipment purchases are planned by the administrators of
a collection operation, the potential effects of equipment size and
design on efficiency should be evaluated.
B. Specific
Based on results of the current study, it is recommended that the
United States Public Health Service, Solid Wastes Program sponsor
additional engineering study in the following areas:
1. The formulation of orderly collection system modification plans
to achieve increased efficiency through reduced crew sizes in harmony
with organized labor requirements, local political factors, and the
need for higher levels of service.
2. The development of time standards, similar to those developed
herein for curbside collections, for other commonly used collection
methodologies including variations of backyard collection, set-out,
and set-out set-back methods.
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3. Comprehensive human factor studies of the interrelationships
between basic work activities, efficiency and safety, and equipment
design to establish work and equipment guidelines for the reduction
of the present relatively high rate of injury to collection personnel.
4. Engineering studies of collection equipment characteristics
and performance to establish guidelines for equipment design and
manufacture in relationship to collection efficiency and human factor
requirements.
5. Use of the extensive statistical data accumulated from this
study's field surveys in a computer simulation program to further
verify the advantages of the one-man collection system, and to prepare
additional illustrative design figures and nomographs to aid the
collection system administrator in improving his operation.
6. Expansion of the engineering methodologies developed herein
by additional studies of refuse collection to reduce labor unrest
and improve socio-economic environmental effects. This can lead
to the reduction of strikes, the promotion of labor-management
harmony, higher collection efficiencies, and better environmental
sanitation.
xxiv
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SUMMARY
The cities of America—indeed of the world—cannot afford to take
their refuse collection systems for granted. Few other activities are
so intimately concerned with the public health, community aesthetics,
and personal contact with the citizen, his home, and his pocketbook.
Only constantly rising standards of productivity can compensate for the
demands of a steadily advancing wage structure. The urgency of the
problem is hardly diminished by the socio-economic implications of the
high minority race representation in many American collection systems.
Refuse collection is big business. Because governmental agencies
are commonly involved, this fact is frequently overlooked. Like other
major industries, refuse collection systems can benefit from in-depth
studies of equipment, methodology, and labor relations—in short, of
all factors relating to efficient operation and high employee morale.
It is believed significant progress has been made as the result of the
study described herein and other studies funded by the Solid Wastes
Program of the United States Public Health Service.
This study has been primarily concerned with determining the
relative efficiency of the one-man collection crew whose single member
serves the dual function of driver and collector. The following methods
were used to compare the efficiency of the one-man crew with that of
the two-, and three-man crews: extensive field studies, time and
motion studies, a mathematical model, and controlled laboratory study.
In the field studies, precautions were taken to ensure the gathering
of reasonably comparable data. For curbside collection, the two- and
three-man crews studied failed to speed collection time sufficiently
over that achieved by the one-man crew to compensate for the additional
man-hours involved. The travel time between stops was approximately
equal for all three crew sizes. Since driving the truck is the only
essential labor function between stops, travel-time is usually non-
productive time for the second and third members of the larger crews.
An exception does exist, however, when routes with narrow alleys or
cul de sacs make operation of a conventional large-capacity truck
difficult without the guidance of an additional crew member during
backing and other tight maneuvering of the vehicle.
At present, the conventional rear-loading packer is believed to be
the most efficient refuse collection equipment currently available for
packing refuse. The side-loading vehicle, however, is more efficient
for use in one-man curbside collection operations, primarily because
it locates the driver immediately adjacent to both loading and container
locations. The TRAC, or Truck Rear Actuated Control device, was designed
to permit one-man operation of the conventional rear-loading truck. In
its present experimental form, it appears to have certain disadvantages
for heavy-duty all-weather use. As a concept, however, it illustrates
both the possibility and the need to produce better equipment specifi-
cally designed for refuse collection.
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Motion-Time-Measurement, or MTM, industrial time standards were
used as an additional tool for the comparative study of different
collection methodologies. Recorded field collection time data were
supported by the MTM results when proper allowance was made for fatigue
and delay factors which had not been assigned standard values, indicating
that industrial MTM methods were indeed suitable for collection efficiency
studies. The field studies, verified by the MTM time and motion analyses,
indicated that the one-man crew was more efficient than either the two-
or three-man crews for curbside and alley collection methods. Using the
MTM standards, all three crew sizes were found approximately equal for
modified curbside collection in which both sides of the street are col-
lected at each collection stop. Similar theoretical analysis indicates
that backyard collections may be accomplished more efficiently with the
two- and three-man crews, particularly when large capacity trucks are
assumed.
A mathematical model was designed to simulate refuse collection
using the three crew sizes under a variety of assumed field conditions.
Basically, the model makes it possible to calculate the probable time
and cost effects of various changes in collection methodology. Using
designated values for system parameters, the model was used to project
unit costs of collection, services collected per crew, and to evaluate
the effect of truck size, for each of the three crew sizes under alterna-
tive methods of collection. The model was also used to test design data
based on the assumption that two- and three-man crews were respectively
one-third and two-thirds faster per collection stop than the one-man crew.
The resulting performance and unit cost curves were not supported by this
study's field and time-motion data, indicating that the assumptions were
not valid.
The use of disposable containers such as plastic or paper sacks was
found to enable a significant reduction in collection time, ranging from
15 to as much as 50 percent, depending on the number of containers re-
placed by the bags. An estimate indicates the cost savings resulting
from reduced collection time and elimination of conventional containers
may compensate for as much as half the cost of both the disposable con-
tainers and their holders. Additional studies in Inglewood, California,
have been initiated to verify these potential savings and to evaluate
disposable container systems.
In preliminary laboratory studies, loading height of the collection
vehicle did not have a significant effect on collector performance
degradation. However, an increase in performance degradation due to
loading height did appear in association with cumulative loads in excess
of 5000 Ib. Container weight, on the other hand, was found to have an
important effect on performance. The critical load-weight point based
on these preliminary studies fell within the range of 45 to 60 Ib per
container. Further study is necessary to define the point more
accurately; such information would he useful since maximum container
weight is usually established by municipal ordinance and should be
XXVI
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related to the efficiency and welfare of the collection employee. Other
collection factors which have a major impact on accidents, injuries, and
man's ability to perform the refuse collection task are recommended for
further study.
Based on an analysis of sample data from 234 cities, the cities
represented provide municipal rather than private refuse collection
service; use a three-man crew; designate a combination of curb and alley
collection location; and use rear-loading packer equipment. Less than
3 percent of the cities reported the use of the one-man crew, and in
descending order of preference, these one-man crews used side-loading,
front-bucket, and rear-loading equipment. Twice as many cities used
three-man crews as did two-man crews, but several cities used four-man,
five-man, and even larger-sized crews, usually in conjunction with yard
carryout service. The reported accident rate was higher in the smaller
cities. The median city's collection cost per ton was approximately $10
for small and medium-sized cities, and $13 for larger cities with popula-
tions in excess of one half million. Reported cost data indicated wide
variation among cities in both cost efficiency and accurate accounting.
In fact, one of the most interesting conclusions to be drawn from an
analysis of the same data is that many American cities have no way of
accurately determining the productivity of their collection dollar
simply because they fail to record adequate refuse quantity and manpower
data.
Improved engineering design of the conventional refuse collection
system is both possible and desirable. In curbside or alley collection,
where route conditions present no special problems and adequate super-
vision is available, the one-man crew has been found to be the most
economical for refuse collection. In residential or light-commercial
areas, the workload is not excessive for one-man collection. In addi-
tion, having sole responsibility for a specific route can encourage
greater pride and improved work habits. One-man collection does require
a responsible attitude on the part of the collector and careful selection
of qualified personnel on the part of the governmental or private col-
lection agency. However, both the employee and the community as a whole
would certainly benefit if the status of the refuse collector and his
essential contribution to the public good received the recognition they
deserve.
XXVll
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I. INTRODUCTION AND PURPOSE
Recent (1968) strikes of sanitation workers in the Cities of
Atlanta, Baltimore, New York, Memphis, Paris, Los Angeles, Santa
Monica, and others have dramatized the importance of refuse collection
to the physical and economic welfare of the urban community. The
general public was also alerted to the costs involved in municipal
refuse collection - many for the first time. An important problem
is whether collector manpower requirements can be reduced to compensate
for higher pay and increased manpower quality while maintaining a
high level of service.
Although, the unit cost of refuse collection does not generally
appear to be excessively high, the magnitude of service required
quickly expands the total costs to a high figure. Collection and
disposal of an estimated 125 million tons of urban refuse produced in
the United States each year costs approximately $3 billion per annum.
Since collection represents about 70 to 80 percent of this cost, refuse
collection is currently at least a $2 billion industry. Furthermore,
not only is the per capita quantity of solid waste expected to increase,
but the total population and industry of the country is expected to
double within the next fifty years. Improvements in collection
efficiency can thus be expected to achieve savings of many millions of
dollars.
In recent years, extensive study has been devoted to improved
refuse disposal techniques and the development of new disposal methods
which incorporate refuse reclamation. However, little concentrated
effort has been expended to understand and improve refuse collection.
In short, large funds have been expended to finance research directed
towards reduction of disposal costs, while even greater potential
savings from reductions in collection costs have been in large part
neglected.
Since most of the population increase will probably continue to be
in urbanized areas, it is reasonable to expect a constant acceleration
in both the area concentration and absolute quantity of solid wastes.
In other words, it will become increasingly necessary to think of
managing refuse in terms of mass production, mass collection, and mass
disposal. Not only can the smaller cities anticipate future possibilities
of growth and experience based on patterns found in the larger munici-
palities, but all jurisdictions should have access to as much factual
information as possible in order to enable intelligent decisions and
prevent costly errors.
Recently, a few collection systems have been employed for curbside
collection of residential refuse wherein one man acts as both driver and
loader. (When words or phrases which are included in the Glossary
first appear, they are underlined). Unofficial reports indicated that
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substantial reductions in the overall costs of providing collection
service were possible using this new system. It was not known whether
the apparent savings were due to the smaller crew size or to a
combination of equipment, collection methodology, routing characteristics,
haul distances, and personnel used by these systems. Ralph Stone and
Company, Inc., Engineers, was therefore authorized by the Solid Wastes
Program, United States Public Health Service, to study and report on
one-man refuse collection operations.
The prime purpose of the study was to define the nature and extent
of the possible savings, if any, due to a one-man crew; to compare the
efficiency of the one-man crew with two- and three-man crews; and to
project the future use of the one-man system for refuse collection. In
addition, a catalogue of the equipment available for one-man operation
was to be compiled.
II. DETAILED APPROACH
Refuse collection is a complex system to analyze, primarily
because it involves both men, equipment, and levels of service plus the
possibility for numerous variations in secondary factors which are
difficult to quantify but have a direct bearing on the overall efficiency
of the system. Some of these factors are: collection methodology;
quantity, nature, and method of storage of the refuse; location of
pickup point; equipment type and characteristics of operation; road
factors; service density; route topography; climatic factors; and a
broad category termed, for lack of a better description, human factors.
Human factors include morale, motivation, fatigue, and other psychological
and physiological factors which influence the time required to complete
a given work task.
For any given refuse collection system, some or all of these
tangible and intangible factors will have significant but perhaps
unknown effects upon the efficiency of collection. Thus, merely
comparing overall system costs and performance rates of numerous
operating systems utilizing various sized crews cannot define the true
nature and cause of differences which may occur in efficiency. Analysis
of comparable aspects of existing systems, however, can provide valuable
information, and various systems were analyzed to disclose interrelation-
ships which might affect relative efficiency. Extensive field surveys
of collection operations were conducted.
Comparisons were limited, however, to easily definable factors to
assure a high degree of comparability. Thus, comparisons were made of
such factors as the incremental time per stop, rather than of overall
man-hours per ton and other typical descriptors which are highly variable
and are influenced by haul distances, truck sizes, and other methodology
alternatives.
-------
Because present day experience with the one-man collection system
has been limited primarily to curbside collection, this method received
the most intensive study. However, preliminary analysis of the
applicability of one-man collection systems to backyard and alley
collections has also been completed.
Mathematical and theoretical approaches were also used to examine
the refuse collection operation under simulated controlled conditions,
thus removing the effect of secondary factors. The mathematical
approach involved the description of the refuse collection system by
formula. Industrial engineering motion-time analysis methods were used
for the theoretical approach. Thus, three complementary approaches were
used to define the relative efficiency of the one-man versus two- or
three-man crews: 1) the conduct of comprehensive field surveys of
selected municipal and private collection operations and the analysis
of field and sample data covering nationwide refuse collection operations;
2) the industrial engineering time and motion analysis, xtfhich vras
confined to the on-route collecting time, to verify the validity of the
field survey data and to define theoretical times for collecting the
refuse based on various equipment designs, collection methodology,
locations of the refuse, and number in the crew; and 3), the mathematical
model, which, when supplied with various combinations of collection time,
travel time, truck capacity, crew sizes, haul time, labor and equipment
costs, and other route factors, permitted estimates of the average level of
efficiency and projections of system costs.
A. Field Surveys and Analysis
1. General
In comparing the relative efficiency of refuse collection
crews, the time to collect the refuse from each service stop is very
important. Assuming that containers do not require two men for lifting
and that collection equipment can be operated by one man, the incremental
time at each service stop is the most important single factor determining
relative efficiency of different size crews. During all time spent for
travel, lunch, relief, and at the disposal site, the relative efficiency
varies inversely with the crew size, except when loader members of the
multi-man crew are productively employed for other work while the
collected refuse is being hauled for disposal. Occasional instances
were noted where loaders were used for sweeping gutters, carrying
emptied containers from the curb to the storage location in the backyard,
and carrying loaded containers from the backyard location to the curb
for subsequent collection. At least one private firm assigned the haul
and disposal time period as. the lunch period for the loaders. Other
minor time considerations, such as unloading at the disposal site, may
also affect the relative efficiency - but not to a significant degree.
-------
In addition, it was thought,there might be a significant difference
in driving time between service stops for one-, two-, and three-member
crews, because positioning equipment in relation to container location
might be more important for the one-man crew. Desirable equipment
types for collection operations using various crew sizes for alternative
collection methodology are discussed in Section D of this report.
At any given curbside service stop, apart from differences
in personnel ability, the collection time depends primarily on the number
and types of containers placed for collection. Therefore, the field
surveys of various municipal and private firm collection operations
included this information in order to correlate the time per stop with
the number and type of containers at each service stop.
A standard form designed for use in the field surveys is
contained in Appendix A. Page 1 of the form includes a description of
the collection operation being surveyed.
2. Field Study Program
A program was initiated in July 1967 to undertake
comprehensive field surveys of selected refuse collection operations
located in California. These field surveys were intended to enable
evaluation of the following:
a. Statistical distribution of collection time for
various crew sizes and collection methodologies.
b. Statistical distribution of travel time between
collection stops.
c. Mean quantity of refuse per service stop and an
estimate of its standard deviation.
d. Time and motion, employing motion picture films and
television video tape recordings of the refuse collection operation
for subsequent analysis.
e. Number and type of containers at each service stop
and the corresponding collection time.
Beginning in early July 1967, contacts were made to
request permission from selected cities and private firms to conduct
a series of field surveys of collection operations. Four cities and
two private collection firms located in California were chosen for
detailed field study. Two private firms and two of the cities used
one-man collection systems. The remaining two cities utilized two-
and three-man crews respectively. Both private firms and three of
the municipalities were located in Southern California. In accordance
-------
with administrative requests, and in order to obtain maximum cooperation,
identities have been withheld. Throughout the report, the following
designations will be used:
Municipality A: Southern California - One-Man Crew
Municipality B: Southern California - Two-Man Crew
Municipality C: Southern California - Three-Man Crew
Municipality D: Central California - One-Man Crew
Private Firm X: Southern California - One-Man Crew
Private Firm Y: Southern California - One-Man Crew
System variables were partially controlled by choosing
systems with similar climates; service areas; and ordinances governing
refuse containers, preparation of refuse for collection, and materials
suitable for collection. Curbside collections were made from one side
of the street with the truck returning in the opposite direction to
collect refuse from the other side of the street. Table I contains
selected comparative information including a summary of the ordinances
governing refuse collection by each private firm and in each municipality.
In addition to the detailed field surveys, abbreviated
field surveys of municipal and private collection operations were made
at other locations throughout the country as described in Table II.
Motion picture film and video tape studies were made of municipal and
private operations. Movie films were subsequently edited to provide
visual comparisons between alternative collection methodologies.
Detailed field surveys for Municipalities A, B, and C
were scheduled concurrently during three periods of the year. The
first series was completed during August of 1967. The second series
began in December and was completed by early February 1968. A third
and final series was started in March and completed in April 1968.
Municipality D and Firms X and Y were surveyed during
the winter and spring period only. Winter surveys commenced in late
October 1967 and were completed in early February 1968. The spring
series began in February 1968 and was completed in April 1968.
In most instances, the surveys involved the study of the
operations of two or more crews for an elapsed time period of two
weeks. Rather than make a random survey of a large number of crews
for short time periods of one or two days, the operations of a few
well-chosen crews were studied for a longer time period (two weeks).
-------
TABLE 1
SUMMARY OF COLLECTION PRACTICES
SELECTED CITIES AND PRIVATE FIRMS
Collection
Agency
Residential
Refuse
Collected
Quantity
Limit
Collection
Location
Container
Size
Max. Vol
(Gal)
Max. Wt
(Lb)
Collection
Frequency
(Per Week)
Truck Size
(Cu Yd)
Crew Size
State
A
Combined
No
Limit
Curb or
Alley
20-40
60
1
35
1
Cali-
fornia
B
Combined
No
Limit
Curb or
Alley
20-45
80
1
25
2
Cali-
fornia
C
Combined
No
Limit
Curb or
Alley
32
75
1
20
3
Cali-
fornia
D
Combusti-
ble Rub-
bish(less
garbage)
No
Limit
Curb-
side
30
70
1
24
1
Cali-
fornia
X
Combined
No
Limit
Curb or
Alley
45
70
2
20
1
Cali-
fornia
Y
Combined
No
Limit
Curb or
Alley
45
70
2
20
2,1
Cali-
fornia
-------
TABLE II
SUMMARY OF COLLECTION PRACTICES
SUPPLEMENTAL CITIES AND PRIVATE FIRMS
Collection
Agency
Residential
Refuse
Collected
Quantity
Limit
Collection
Location
Container
Size
Max. Vol
(Gal)
Max. Wt
(Lb)
Collection
Frequency
(Per Week)
Truck Size
(Cu Yd)
Crew Size
State
1
Mixed
No
Limit
Curb-
side
2 cu ft
100
2-6
16
3
New
York
2
Combined
No
Limit
Back-
yard
27
75
1
20
3,4
Ohio
3
Combined
No
Limit
Curb or
Alley
30
—
2
17
2
Cali-
fornia
4
Combined
No
Limit
Curb or
Alley
50
5
Combined,
less
garden
refuse
6
Combined
i
No
No
Limit Limit
1
Back-
yard
—
80
1
25
2
Cali-
fornia
1
25
3
Cali-
fornia
Curb or
Alley
32
50
2
20,25
3,2
Cali-
fornia
-------
TABLE II (Continued)
Collection
Agency
Residential
Refuse
Collected
Quantity
Limit
Collection
Location
Container
Size
Max. Vol
(Gal)
Max. Wt
(Lb)
Collection
Frequency
(Per Week)
Truck Size
Crew Size
State
7
Combined ,
less
garden
refuse
No
Limit
Curb/
Alley or
Backyard
—
—
1
Varies
5
Ohio
8
Combined,
less
garden
refuse
No
Limit
Curb or
Alley
9
Combusti-
ble (less
garbage)
_ „
Curb or
Alley
I
30
75
2
—
1&2
20
3
Arizona
25
5
British
Columbia
10
Combusti-
ble (less
garbage)
No
Limit
Back-
yard
—
2
25
4
Florida
11
Combined
No
Limit
Curb or
Alley
12
Combined ,
less
garden
refuse
Back-
yard
i
32
100
1 2
25 20
3,2
Cali-
fornia
4,5
Georgia
-------
TABLE II (Continued)
Collection
Agency
Residential
Refuse
Collected
Quantity
Limit
Collection
Location
Container
Size
Max. Vol
(Gal)
Max. Wt
(Lb)
Collection
Frequency
(Per Week)
Truck Size
Crew Size
State
13
Combined
No
Limit
Curb or
Alley
— —
__
1
20
A
Illinois
14
Combined
No
Limit
Curb or
Alley
__
...
2
20
3
Pennsyl-
vania
-------
Short term surveys of a collection crew's operations, especially those
involving detailed time studies, may temporarily affect the work rate
of the crew. Such short term effects are probably nullified when the
same crew is studied over a longer period of time.
The field survey was conducted by Company staff who followed
and recorded the collection operations of a single crew during the
entire work day during each day of the two-week survey series. Normally,
one crew was studied for the first week and a different crew for the
second week. At each service stop, the number and type of containers,
collection time, the travel time to the next stop, and the elapsed time
and its cause for any measurable delays were noted. Examples of such
delays were lost time due to tagging illegal containers, operation of
the packer cycle at the stop, cleanup of spilled refuse containers, and
so forth. Many other delays could not be recorded due to their extremely
short duration or difficulty in determining the precise moment they
began. This category would include the effect of a parked car, wiping
off perspiration, removing lids from containers, and numerous other
occurrences. Supplemental video tape studies were used to measure this
type of lost time.
To facilitate the use of the data forms and to record the
incremental collection and travel times for each stop, timing boards
typically used for industrial time and motion studies were employed.
Photograph I illustrates the timing board which enables accurate record-
ing of the times of consecutive operations; for example, the collection
of refuse from one collection stop and the travel to the next collection
stop.
Routes selected for detailed field study in Municipalities
A, B, C, and D, and Firms X and Y, were based on the following criteria:
curbside collection of residential refuse (some alley collections were
also included); predominately single family residential service area;
average income area; minimum number of route obstructions, such as cul
de sacSj dead end alleys, and construction; and level topography.
These desirable route characteristics were chosen to make
technical data as comparable as possible. In addition, defining the
route and service conditions enabled the data to be compared with data
from other cities with similar conditions. Projections of results to
other common practices, such as backyard collection, are included in a
later section of this report.
Typical crews were selected for detailed study following
discussions with collection system managers. When available, prior
records of crew performance were consulted to aid in crew selections.
The nature and general purpose of the survey was explained to the crews,
and their support in obtaining meaningful results was requested. Crews
were instructed to complete their routes in a normal manner. A copy of
the data for each day of the detailed field surveys is enclosed as a
separate Attachment A to this report.
10
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PHOTOGRAPH I.
FIELD SURVEY
TIMING BOARD
•Pplrtwhb,
PHOTOGRAPH II
EQUIPMENT - MUNICIPALITY B
PHOTOGRAPH III
EQUIPMENT - MUNICIPALITY C.
r /
PHOTOGRAPH IV.
EQUIPMENT - MUNICIPALITY A
11
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Each day's survey data for a particular crew was summarized
on the data summary form included as Appendix B. Copies of the data
summaries are provided in separate Attachment B and were the basis for
detailed analysis to evaluate refuse collection practices.
3. Results - Field Surveys
The field survey data is summarized in Tables III, IV, and
V, and is graphically presented in Figures 1 through 26. Table III con-
tains summary information on the mean quantity of refuse per service
stop and the estimate of its standard deviation. The estimate of the
standard deviation of the load mean quantity of refuse per service stop
was obtained by the following procedure: the total number of services
collected (SC) in each truck load of net weight (W) was determined.
The load mean quantity of refuse per service stop (q) for each load was
calculated from the following:
(q). = - Hi - i - 1, 2,.n, load number
(SC)i
The mean refuse quantity per service stop (Q) for each field
survey period and for the composite was calculated from the following:
n
I W±
Q = _i=l -
n
The standard deviation of the load mean refuse quantity per
stop was calculated from the following:
Z (qi - Q)
n
The statistic man^minutes/ton has been commonly used as a
measure of the performance of collection crews; unfortunately, it is
not directly comparable between all types of refuse collection methodo-
logy. However, it is useful for comparison when operations using
similar methodology are considered. It has been calculated for Muni-
cipalities A, B, C, and D, and for Firms X and Y, and is tabulated in
Table IV. A similar calculation for certain other surveys is shown in
Table V. In order for the statistic to be directly comparable between
the systems surveyed , the mean and standard deviation of the quantity of
refuse per service stop and the distribution of containers would have
to be equal. Table IV and Figures 1 and 2 illustrate the similarity in
12
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TABLE III
FIELD.SURVEY SUMMARY DATA - DETAILED SURVEYS
Collection
Agency
Season
Municipality A
Summer
Winter
Spring
Composite
Municipality B
Summer
Winter
Spring
Composite
Municipality C
Summer
Wint er
Spring
Composite
Municipality D
Winter
Spring
Composite
Firm X
Winter
Spring
Composite
Firm Y
Winter
Spring
Composite
Mean Refuse
Quantity
(Lb/Stop)
80.75
65.1
88.23
77.11
83.02
81.70
78.86
81.25
71.99
69.04
76.28
73.20
53.86
59.35
56.87
81.19
93.68
88.07
56.26
66.38
60.54
Load Standard
Deviation
(Lb/Stop)
8.43
11.74
11.46
14.25
6.47
16.87
15.62
13.38
4.60
9.16
20.25
14.07
6.71
9.03
8.74
12.41
25.71
22.19
11.91
23.28
18.26
Surveys Included
8/67
12/67
4/68
8/67
1/68 - 2/68
4/68
8/67
1/68
3/68 - 4/68
11/67 - 2/68
3/68 - 4/68
10/67
2/68 - 4/68
11/67 - 2/68
4/68
13
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TABLE IV
ROUTE MAN-MINUTES PER TON
Agency
Municipality A
Municipality B
Municipality C
Municipality D
Firm X
Firm Y
Crew
Size
1
2
3
1
1
1
Mean
Man-Minutes /Ton
26.25
43.00
63.53
37.57
33.84
39.05
Standard^1'
Deviation
4.64
9.89
7.33
8.70
7.36
10.37
Standard Deviation of Mean Man-Minutes/Ton
14
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TABLE V
FIELD SURVEY SUMMARY DATA - ABBREVIATED SURVEYS
City or
Private Firm
1
3
4 (one-man)
4 (two-man)
5 (P)(3)
6
Quantity of Refuse
Per Collection Stop
(Lb)
Mean
33.71
62.60
70.12
82.44
110.19
126.28
SD
5.10
23.22
4.81
10.31
—
12.86
Man-Minutes Per Ton
Mean
119.95
113.96
25.66
38.18
103.34
115.81
SD<2>
25.99
36.05
2.77
5.11
—
34.28
(1) Field Surveys conducted for one week or less.
(2) standard Deviation of the Mean.
(3) private Firm
LIBRARY
Environmental Frct&ticn /"gency
5555 Ridge Ave., Cincinnati, 0. 45213
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Municipalities A, B, and C and, to a lesser degree, in Municipality D
and Firms X and Y. To remove the effect of haul time, volumetric ca-
pacity of equipment, and other factors affecting each municipality and
private firm, man-minutes/ton were calculated only for the time interval
during which the crews were on the collection route, including travel
time between stops. Break time, lunch time, and other nonproductive
periods were excluded from the calculations. The inclusion of non-
productive time, haul, and disposal time, would all have the effect of
increasing each respective man-minute per ton figure; however, to a
much greater degree for the two- and three-man crew for reasons previously
noted.
Figures 1 and 2 illustrate the statistical distribution of
cans and total items at the service stop, respectively. Figures 3
through 7 illustrate the approximate statistical distribution of the
collection time for one through five cans respectively from the curbside
location for the three indicated municipal collection studies. These
data were determined following a total of six weeks of detailed field
survey in each city. The plots were constructed by joining the mid-
interval points of histograms constructed from the field data.
As indicated by these figures, the disparity in average
collection time between crews for equal numbers of cans increases as
the number of cans increases. This would be the expected result since
the second or third crew man becomes more effective when there are two
or more cans at the service stop. However, note the similarity in the
shape of the curves regardless of the number of cans. Typically, the
driver member of the two-man crew is instructed to leave the cab to aid
the loader only if three or more items are to be loaded at a service
stop. In the three-man operation surveyed, the driver always remained
in the cab of the truck. Therefore, assuming personnel and route fac-
tors were equal, the only differences expected between crews in Figures
3 and A would be those due to the work procedure at the service stop.
In both the two- and three-man crews, the receiving hopper
and the loader are located at the rear of the packer truck. For the one-
man crew, the surveyed operation used a side-loading packer equipped
with right-hand drive. Photographs II, III, and IV illustrate collection
operations in each instance.
Figure 8 illustrates the overall average collection time.per
stop, based on all field study data, regardless of the number of items
at the stop.
Figure 9 illustrates the average collection time for one
through seven cans at the curb location by Municipalities A, B, and C.
A least squares line has been calculated to represent the data. Figure
9 is, therefore, a plot representing the mean time values from Figures
3 through 7- The data indicates that for the conditions and crews
sampled in these three municipalities, the increased rate of handling
16
-------
0
AGENCY
Municipality A
Municipality B
Municipality C
MEAN NO. OF
CANS PER STOP
2.45
2.65
2.70
1 23456 7 89 10
0
FIGURE 1
PISTRIBUTION
CANS
AT COLLECTION STOP
17
-------
60
50
AGENCY
Municipality A
Municipality B
Municipality C
MEAN NO. OF
ITEMS PER STOP
3.40
3.55
4.01
MUNICIPALITY B
MUNICIPALITY C
01 23456 789 10 11 12
MUNICIPALITY A
FIGURE 2
DISTRIBUTION
ITEMS AT COLLECTION STOP
18
-------
AGENCY
Municipality A
Municipality B
Municipality C
CREW
SIZE
1
2
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.278
0.223
0.214
MUNICIPALITY C
0 0.1 0.3 0.5 0.7 0.9 1.1
TIME (MINUTES)
1.3 1.5 1.7 1.9 2.1
FIGURES
DISTRIBUTION
COLLECTION TIME
ONE CAN
19
-------
70
u
z
LU
13
a
0
AGENCY
Municipality A
Municipality B
Municipality C
CREW
SIZE
1
2
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.456
0.383
0.311
MUNICIPALITY A
0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2J
TIME (MINUTES)
FIGURE 4
DISTRIBUTION
COLLECTION TIME
TWO CANS
20
-------
70
60
50
40
O
<
LU
fe 30
UJ
^
O
LU
Sf 20
10
o
AGENCY
Municipality A
Municipality B
Municipality C
CREW
SIZE
1
2
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.620
0.558
0.454
MUNICIPALITY A
MUNICIPALITY C
MUNICIPALITY B
00.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1
TIME (MINUTES)
FIGURE 5
DISTRIBUTION
COLLECTION TIME
THREE CANS
21
-------
70
60
50
40
30
20
10
0
AGENCY
Municipality A
Municipality B
Municipality B
CREW
SIZE
1
2
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.793
0.705
0.558
MUNICIPALITY A
MUNICIPALITY B
0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1
TIME (MINUTES)
FIGURE 6
DISTRIBUTION
COLLECTION TIME
FOUR CANS
22
-------
70
60
50
AGENCY
Municipality A
Municipality B
Municipality C
CREW
SIZE
1
2
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
1.161
0.863
0.716
40
iir
o
| 30
LU
U
z
LLJ
D 20
10
0
MUNICIPALITY C
MUNICIPALITY B
MUNICIPALITY A
0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1
TIME (MINUTES)
FIGURE 7
DISTRIBUTION
COLLECTION TIME
FIVE CANS
23
-------
70
60
50
O
Z
LLJ
40
30
LU
o
LU
C£
20
10
0
AGENCY
Municipality A
Municipality B
Municipality C
CREW
SIZE
1
2
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.68
0.59
0.58
MUNICJPALITY C
MUNICIPALITY B
MUNICIPALITY A
0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
TIME (MINUTES)
FIGURE 8
DISTRIBUTION
COLLECTION TIME
PER STOP
24
-------
LJJ
2.0
1.8
1.6
1.4
1.2
„
0.8
0.6
0.4
0.2
AGENCY
Municipality A
Municipality B
Municipality C
CREW
SIZE
1
2
3
MUNICIPALITY B
MUNICIPALITY C
0
234 5 67
CANS AT COLLECTION STOP (NUMBER)
FIGURE 9
FIELD SURVEY
AVERAGE COLLECTION TIME
PER STOP
25
-------
containers possible at each collection stop with multi-man crews is not
sufficient to compensate for the associated increased man-hours —
double in the case of the two-man crew, and triple in the case of the
three-man crew. Figure 10 is a similar plot of average collection time
for disposable items.
Figure 11 illustrates the distribution of the travel time
between stops. No significant difference in travel time between stops
appears to result from the addition of a man who acts solely or primarily
as a driver. Lot widths in the surveyed areas were about the same,
averaging about 50 ft. Collection equipment participating in the studies
was equipped with automatic transmission. Film studies of Municipality
A indicated that the drivers consistently set the brakes and stepped
from the cab before the equipment had completely stopped, which perhaps
accounted for the slightly less mean travel time recorded for the
municipality. Although several hundred service stops are made each day,
the differences illustrated are not considered important in total time;
e.g., a difference of 0.02 minutes per collection stop would only total
6 minutes per day if 300 stops were made by the crew. In efficiency
comparisons using the mathematical model presented in Section D, the
travel time between curbside service stops was assumed constant at 0.17
minutes.
Figures 12 through 19 illustrate the statistical distribu-
tions of cans, total items, and collection times for Firms X and Y and
for Municipality D. Figures 20 through 25 illustrate the collection
time per stop and the average collection time for stops composed of from
one to seven cans for Municipalities 1 through 6 where the abbreviated
surveys were conducted.
The following general comments can be made by studying
Figures 20 through 25. Increasing the crew size usually reduces the
mean collection time per stop by some amount, causing the distribu-
tion of collection time to become skewed more to the left part of the
curves. Increasing the frequency of collection did not result in any
apparent decrease in the collection time per stop (see Figures 20 and
21). Figure 22 illustrates the differences in collection time occurring
between a backyard and curbside set-out system. Other variable factors
between the two Municipalities may have contributed to their differences;
however, a considerable range would be expected. Figure 23 illustrates
differences that do occur between two municipalities, even though from
Table II, the operation appears to be somewhat similar. Figure 24 il-
lustrates the curbside collection time for a four-man crew. Comparison
with Figure 9 indicates that only minor time differences occur between
the four- and the three-man crews for comparable collection stops, thus
continuing the trend shown on Figure 8. Figure 25 illustrates the
collection time for stops composed of from 1 to 7 cans by Municipalities
4 and 3. Note the apparent similarity between the two crews of Munici-
pality 4 with the same size crews of Municipalities A and B on Figure 9.
26
-------
2.0
1,8
1.6
AGENCY
o Municipality A
o Municipality B
A Municipality C
CREW
SIZE
1
2
3
1-4
1.2
z i.o
LLJ
1 0.8
0.6
0.4
0.2
0
0
MUNICIPALITY B
MUNICIPALITY C
MUNICIPALITY A
23456 78
DISPOSABLES AT STOP (NUMBER)
FIGURE 10
FIELD SURVEY
AVERAGE COLLECTION TIME
DISPOSABLES ONLY
27
-------
60
55
50
45
40
LLJ
o
< 35
Z
LLJ
^30
Z
LLJ
a 20
a-:
15
10
0
AGENCY
Municipality A
Municipality B
Municipality C
CREW
SIZE
1
2
3
MEAN TRAVEL
TIME PER STOP
(MINUTES)
0.153
0.170
0.174
MUNICIPALITY C
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1
TIME (MINUTES)
FIGURE 11
DISTRIBUTION
TRAVEL TIME BETWEEN
COLLECTION STOPS
28
-------
to
LLJ
o
LLJ
LU
D
O
LU
20 -
10
AGENCY
Municipality D
MEAN NO. OF
CANS PER STOP
1.79
CREW
SIZE
1
0
MUNICIPALITY D
CANS (NUMBER)
29
FIGURE 12
DISTRIBUTION
CANS
AT COLLECTION STOP
-------
60.-
50 -
O 40 -
z
u
LLJ
fe
30
U
z
LLJ
-
fx
- < x
./ ^,
a
LLJ
^ 20 -
10
AGENCY
Municipality D
MEAN NO. OF
ITEMS PER STOP
2.60
CREW
SIZE
1
MUNICIPALITY D
2345678
ITEMS (NUMBER)
10 11 12
FIGURE 13
DISTRIBUTION
ITEMS AT COLLECTION STOP
30
-------
70
60
AGENCY
Municipality D
CREW
SIZE
1
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.568
50
O
-------
2.0
1.8
1.6
AGENCY
Municipality D
CREW
SIZE
1
1.4
1.2
?. 1.0
0.8
0.6.
0.4
0.2
y
MUNICIPALITY D
234 567
CANS AT COLLECTION STOP (NUMBER)
FIGURE 15
AVERAGE
COLLECTION TIME
32
-------
60 •-
50 -
o
<
z
LU
u
ID
a
LU
AGENCY
Firm X
Firm Y
MEAN NUMBER
OF CANS
PER STOP
2.74
2.07
CREW
SIZE
1
1
0
4567
CANS (NUM&ER)
10
33
FIGURE 16
DISTRIBUTION
CANS
AT COLLECTION STOP
-------
60
50
O 40
i—
z
LLJ
LU
fe
30
LLJ
13
a
LU
20
10
AGENCY
FirmX
FirmY
MEAN NUMBER
OF CANS
PER STOP
4.04
2.87
CREW
SIZE
1
1
FIRMY
FIRMX
.T^-—.
o
2 34 567 8 9 10 11 12
ITEMS (NUMBER)
FIGURE 17
DISTRIBUTION
ITEMS PER COLLECTION STOP
34
-------
70
60
50
O
<
U
Qi
40
z
^ 30
a
UJ
20
10
AGENCY
FIrmX
Firm Y
CREW
SIZE
1
1
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.993
0.587
FIRMY
FIRMX
•^^
0 0.1 0.3 0.5
0.7 0.9 1.1 1.3 1.5
TIME (MINUTES)
1.7 1.9 2.1
FIGURE 18
DISTRIBUTION
COLLECTION TIME
PER STOP
35
-------
2.00
1.80
AGENCY
A Firm X
o Firm Y
CREW
SIZE
1
1
=>
Z
1.60
1.40
1.20
1.00
0.80
0.60
0.40
0.20
FIRMX
FIRMY
0
0 1
456
CANS (NUMBER)
FIGURE 19
AVERAGE
COLLECTION TIME
PER STOP
36
-------
o
I—
z
LU
u
b
a
LU
60
50
40
30
20
10
0
AGENCY
Municipality 1
Municipality 6
SIZE
3
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.531
0.925
,,.j
MUNICIPALITY 1
0 0.1 0.3 0.5 0.7 0.9 1.1 1.3
TIME (MINUTES)
1.5 1.7 1.9 2.0
37
FIGURE 20
DISTRIBUTION
COLLECTION TIME
PER STOP
-------
60
50
40
O
<
u
a:
O
z
O
LU
5f 20
30
10
AGENCY
Municipality 3
Municipality 4
Municipality 4
CREW
SIZE
2
1
2
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.763
0.620
0.491
MUNICIPALITY 4
MUNICIPALITY 4
CS = 1
MUNICIPALITY 3
•••I
0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.0
TIME (MINUTES)
38
FIGURE 21
DISTRIBUTION
COLLECTION TIME
PER STOP
-------
60
50
O
<
I—
z
LU
u
40
30
z
LU
O
LU
20
10
0
AGENCY
Municipality 2
Municipality 5
CREW
SIZE
4
3
MEAN COLLECTION
TIME PER STOP
(MINUTES)
0.377
0.946
MUNICIPALITY 2
MUNICIPALITY 5
0 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
TIME (MINUTES)
2.0
FIGURE 22
DISTRIBUTION
COLLECTION TIME
PER STOP
39
-------
2.0
1.8
1.6
1.4
LU
1.2
z
UJ 1 .0
H^
0.8
0.6
0.4
0.2
AGENCY
n
o
Municipality 1
Municipality 6
CREW
SIZE
3
3
MUNICIPALITY 6
MUNICIPALITY 1
23 4 567
CANS (NUMBER)
40
FIGURE 23
AVERAGE
COLLECTION TIME
PER STOP
-------
2.0
1.8
1.6
1.4
ii.2
s
LU
2 1.0
0.8
0.6
0.4
0.2
AGENCY
Municipality 2
CREW
SIZE
4
MUNICIPALITY 2
X".
?„""
./''
012345678
CANS (NUMBER)
41
FIGURE 24
AVERAGE
COLLECTION TIME
PER STOP
-------
to
LJJ
I—
D
z
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
AGENCY
A
0
a
Municipality 3
Municipality 4
Municipality 4
CREW
SIZE
2
1
2
*
MUNICIPALITY 3
MUNICIPALITY 4
CS =
0
0
345
CANS (NUMBER)
42
FIGURE 25
AVERAGE COLLECTION TIME
PER STOP
-------
2.0
1.8
1.6
1.4
AGENCY
Municipality 4
1.2
LLJ
z
1.0
0.8
0.6
0.4
0.2
ONE-MAN CREW
DISPOSABLES
ONE-MAN CREW
CANS
TWO-MAN CREW
DISPOSABLES
TWO-MAN CREW
CANS
3456
ITEMS (NUMBER)
8
FIGURE 26
COLLECTION TIME -
CANS AND DISPOSABLES
43
-------
Detailed analysis of the field data indicated that the use
of disposable containers, such as bags or sacks, may effect a significant
reduction in the collection time per stop. A comparison of Figure 10
with Figure 9 illustrates that the use of disposable containers might
enable a 15 to 50 percent reduction in collection time per stop if the
conventional containers are replaced by disposable containers on a one-
for-one basis. A Public Health Service-sponsored demonstration of the
feasibility of improved collection service using disposable bags is now
being performed at Inglewood, California.
The concept is illustrated further in Figure 26. Results of
two crews operating concurrently in the same municipality on trucks
which were identical, except that one was equipped with a "TRAC" (Truck
Rear Actuated Control) device to facilitate one-man operation of the
conventional rear-loading packer vehicle, are illustrated. The device,
illustrated in Photographs V and VI, enables operation of the rear-
loading packer from a position adjacent to the loading hopper. The
truck travels in reverse during collection, with the operator conven-
iently located adjacent to both the curbside location of the refuse
containers and the loading hopper of the truck. Following completion
of the loading phase, the device is disengaged, swung to the storage
position behind the vehicle, and the truck proceeds in the normal manner
to the disposal site. Municipality 4 has been evaluating the device for
approximately one year.
Referring again to Figure 26, in comparing the curves of the
time per stop for one man collecting cans using the TRAC unit with the
time per stop for the two-man crew collecting cans, potential savings in
man-minutes per collection stop range from 30 to 40 percent between the
two systems. Note that it is necessary to multiply the collection time
per stop for the two-man crew by a factor of two in order to obtain
man-minutes per stop. This potential timesaving could be expected to
increase when haul time and non-productive time are considered. During
extensive studies of the TRAC unit conducted by Municipality 4 and veri-
fied by the current studies, the average man-hour saving on the route
was about 26 percent. In terms of the total man-hours used during the
day, there was a saving of 38 percent. Although the TRAC unit is not
fully satisfactory for all-weather heavy-duty use in its present form,
the concept underscores the potential savings possible by re-designing
the man-machine combination for the collection task.
B. National Survey of Collection Practice
A total of 234 cities in 42 different States, with a total
population of 37,397,837, have cooperated in our studies by supplying
system data. Copies of the data form are appended to this report (see
Appendix D). Figure 27 illustrates the location of these cities in the
United States, and Table VI is a tabulation by State. Table VII illus-
trates the number of responding cities in each population range.
44
-------
PHOTOGRAPH V.
TRAC - DRIVING
\
PHOTOGRAPH VI.
TRAC - LOADING
45
-------
TABLE VI
NUMBER OF CITIES IN EACH STATE
(INCLUDING DISTRICT OF COLUMBIA)
SUPPLYING COLLECTION DATA
Alabama 3 '
i
Alaska 2 '
Arizona 3
Arkansas 0
California 50
Colorado 1
Connecticut 3
Washington B.C. 1
Delaware 1
Florida 12
Georgia 2
Hawaii 2
Idaho 1
Illinois 5
Indiana 1
Iowa 2
Kansas 1
Kentucky 0
Louisiana 0
Maine 3
Maryland 5
Massachusetts 2
Michigan 10
Minnesota 1
Mississippi 0
Missouri 2
Montana 1
Nebraska 2
Nevada 1
New Hampshire 1
New Jersey 4
New Mexico 0
New York 8
North Carolina 3
North Dakota 3
Ohio 14
Oklahoma 3
Oregon 9
Pennsylvania 9
Rhode Island 0
South Carolina 0
South Dakota 2
Tennessee 5
Texas 21
Utah 1
Vermont 0
Virginia 12
Washington 6
West Virginia 1
Wisconsin 10
Wyoming 2
(Unknown) 3
234 cities responded
42 states represented
-------
TABLE VII
POPULATION REPRESENTED BY 234 CITIES
RESPONDING TO DATA SURVEY
Population (1,000's)
10 - 100
100 - 500
500 and over
Total
No. of Cities
179
38
17
234
Total Population
7,021,153
8,266,790
22,109,874
37,397,817
TABLE VIII
TYPE OF COLLECTION SERVICE
REPORTED BY RESPONDING CITIES;
Population (1,000's)
10 - 100
100 - 500
500 and over
Total
Municipal
108
30
13
151
Private
59
5
1
65
Both
1
12
3
3
18
1
47
-------
CITIES REPRESENTED IN SOLID
WASTE COLLECTION SURVEY
-------
1. Public vs Private Collection Service
The ratio of cities providing public collection service
as opposed to private collection service in the survey sample was
approximately two and a half to one. Although cities with populations
of less than 100,000 had a ratio of two to one in favor of public col-
lection, the larger cities indicated an even greater preference for
public collection over private collection. A number of cities, less
than 10 percent of the sample, reported using a combination of public
and private collection services.(Table VIII).
2. Type of Equipment
Based on the sample data, rear-loading equipment
received the greatest use in refuse collection systems. An analysis of
5018 units of collection equipment revealed that the four leading types
in descending order of preference were: rear-loading; side-loading;
container; and front bucket (Table IX). However, the last two together
comprised less than 5 percent of the total, while side-loaders comprised
8.2 percent. More than 87 percent of the units in this data sample were
rear-loading equipment. A number of cities, however, while using them
for the major proportion of their collection activities, also reported
the need for auxiliary types of equipment for special functions or un-
usual situations such as spring cleanup or access problems in unusually
narrow winding roads. A number of cities used side-loading equipment
almost exclusively. The preference for rear-loading equipment was most
noticeable in the largest cities with populations greater than half a
million. These metropolitan areas reported using 3106 rear-loaders
compared with only 96 side-loaders; thus the former comprised 94.5 per-
cent and the latter 3.0 percent of the total units reported by this
large-city category.
3. Capacity of Equipment
A sample of 77 cities (Table X) was analyzed to determine
the average capacity of collection equipment units based on once a week
versus twice a week collection. In the 10,000 to 100,000 population
range, there was little difference for the 52 reporting cities. The
average capacity per unit was 18.6 cu yd for once a week collection,
and 18.5 cu yd for twice a week collection. A greater difference
appeared among the 17 cities in the 100,000 to 500,000 population
range where equipment for once a week collection averaged 21.4 cu yd,
while equipment for twice a week collection averaged 17.8 cu yd; hence,
the average unit capacity for once a week collection was approximately
20 percent larger than for twice a week. For the eight largest cities
in this sample (those with minimum populations of half a million) there
was no important difference in average capacity based on once a week
versus twice a week collection. The former was 19.4 cu yd and the
latter 18.8 cu yd.
49
-------
TABLE IX
EQUIPMENT ACCORDING TO TYPE
(NUMBER OF PIECES OF EQUIPMENT)
Population
(1,000's)
10 - 100
100 - 500
500 and over
Total
Rear Loading
No. Percent
586 77.6
680 69.5
3,106 94.5
4,372 87.2
Side Loading
No. Percent
128 17.0
185 18.9
96 3.0
409 8.2
Front Bucket
No. Percent
34 4.5
58 5.9
92 1.8
Container
No. Percent
7 0.9
56 5.7
82 2.5
145 2.8
Totals
No.
755
979
3,284
5,018
-------
TABLE X
AVERAGE CAPACITY OF EQUIPMENT (WEIGHTED BY NO. UNITS)
COMPARED WITH SIZE OF CITY FOR ONCE A WEEK AND TWICE
A WEEK COLLECTION (77 CITIES)
Population Class
(1000' s)
From To Less Than
10- 20
20- 30
30- 40
40- 50
50- 60
60- 70
70- 80
80- 90
90- 100
Combined Average
100- 200
200- 300
300- 400
400- 500
Combined Average
500 and over
No.
Cities
3
6
3
2
4
2
2
1
2
25
5
2
2
0
9
5
Average
Capacity
Equipment
Once/Week
Collection
(Cu Yd)
17.6
14.7
24.5
15.3
16.5
25.5
16.0
18.0
17.4
18.6
24.5
17.0
17.8
-
21.4
19.4
No.
Cities
9
5
3
3
3
1
0
1
2
27
2
2
3
1
8
3
Average
Capacity
Equipment
Twice /Week
Collection
(Cu Yd)
18.2
16.5
14.0
17.3
21.7
30.0
-
18.0
23.4
18.5
18.9
15.8
17.8
20.5
17.8
18.77
51
-------
4. Crew Size
The majority of American sanitation collection equipment
represented in the sample was serviced by a three-man crew (Table XI).
In fact, the data indicates that the major portion of solid waste was
collected by a three-man crew using a rear-loading compactor (Table XII).
Less than 3 percent of the cities reported exclusive use of a one-man
crew, while an additional 5-1/2 percent used one-man crews as an adjunct
to larger crew sizes. Eight cities in the 10,000 to 100,000 population
range reported using one-man crews exclusively. Five of these eight
cities provided side-loading equipment; two preferred front-buckets; and
one used rear loaders. Although this data was based on a small sample,
it indicated that side-loading equipment may presently be favored for
use by the one-man crew.
Although three-man crews were most typical in the sample,
a large number of rear-loading units were serviced by two-man crews. An
analysis of 36 larger cities (populations of 100,000 and over) shows that
out of 3489 rear loaders, approximately 73.4 percent used three-man crews
(Table XIII). In the same sample, 104 side loaders were serviced 57.7
percent by three-man crews and 42.3 percent by two-man crews. This
again supports the conclusion that side-loading equipment was more popu-
lar for smaller crew sizes than rear-loading equipment.
When crew size was compared with pick-up location (Table
XIV), the three-man crew remained the major choice of most cities in the
sample for most pick-up points. Based on a study of 136 cities, 54.4
percent of the cities used three-man crews as opposed to 27.9 percent
who used two-man crews. Larger crews were used in significant numbers
only when yard carryout service was provided by the city. Of the 17
cities using four- or five-man crews, nine provided yard service
exclusively, and two used a combination of yard and either curb or alley
service.
5. Pick-Up Location
The most common locations designated for municipal refuse
collection were a combination of curb and alley. In an analysis of 206
cities (Table XV), 77 provided for curb and alley pick-up; 42 collected
at the curb exclusively; 33 provided carry-out service exclusively; 10
provided exclusive alley pick-up; and the remaining 44 combined backyard
carryout service with curbside and/or alley pick-up.
6. Frequency of Collection
There was no strong statistical preference for either
once or twice a week collection in the sampled cities. In a study of
112 cities, 51 cities, or 45.5 percent, provided once a week residential
collection; 55 cities, or 49.1 percent, collected twice a week; and 6
cities, or 5.4 percent, collected three times per week (Table XVI).
52
-------
TABLE XI
NORMAL CREW SIZE OR SIZES
(BY NO. OF CITIES)
Population
(1,000's)
10
to
100
100
to
500
500
and
over
Subtotal
Total
Crew Size
(No. of Men, Including Driver)
1
8
0
0
8
2
31
7
3
41
3
61
13
6
80
4
7
0
1
8
5
5
2
1
8
9
1
0
0
1
146
1,2
6
0
0
6
1,3
7
2
1
10
2,3
13
2
1
16
2,4
1
0
0
1
3,4
2
0
1
3
3,5
2
0
0
2
4,5
1
1
1
3
1,2,3
2
0
0
2
4,5,6
0
0
1
1
2,4,5
1
0
0
1
1,2,3,4
0
1
0
1
46
in
U)
-------
TABLE XII
CREW SIZE ACCORDING TO TYPE OF EQUIPMENT
Population
(1,000's)
(No. of Cities]
10
to
100
(89 Cities)
100
to
500
(29 Cities)
500
and
over
(15 Cities)
Total
No. of
Men In
Crew
1
2
3
4
5
Varying
1
2
3
4
5
1
2
3
4
5
Varying
Type of Equipment by Number of Cities
Rear Loader
1
17
43
3
4
4
.
6
10
1
1
—
3
6
1
-
1
101
Side Loader
5
6
11
1
1
1
—
3
4
1
~
.
2
2
-
_
-
37
Front Bucket
2
-
2
-
-
2
—
2
1
-
—
.
-
-
-
-
—
9
54
-------
TABLE XIII
TOTAL NUMBER OF UNITS OF EQUIPMENT
ACCORDING TO TYPE OF EQUIPMENT
AND CREW SIZE (FOR 36 LARGER CITIES/1'
Ul
Ln
Population
(1,000's)
(No. of Cities)
100 -
500
(25 Cities)
Subtotal
500
and over
(11 Cities)
Subtotal
Total
No. of
Men in
Crew
2
3
5
2
3
4
Rear Loader
No. of
Cities
6
10
1
17
3
6
1
10
27
No. of
Units of
Equipment
135
271
49
455
649
2,289
96
3,034
3,489
Side Loader
No. of
Cities
3
4
-
7
2
2
-
4
11
No. of
Units of
Equipment
33
45
-
78
11
15
-
26
104
Front Bucket
No. of
Cities
2
1
-
3
-
-
-
3
No. of
Units of
Equipment
20
3
-
23
-
-
-
23
(1)
The number of cities may not seem to correspond with the data only because any one
city may be listed more than once under different types of equipment.
-------
TABLE XIV
CREW SIZE BY LOCATION OF PICKUP
(136 CITIES)
(BY NUMBER OF CITIES)
Population
(1,000's)
10 -
100
Crew
Size
1
2
3
4
5
Total
C
A
Y
C&A
Y&A
C&Y
C,A&Y
Total
Number of Cities
_
8
17
1
-
26
1
-
3
-
-
4
1
3
6
4
4
18
5
11
20
2
-
38
-
3
1
-
1
5
-
1
5
-
-
6
-
2
2
-
-
4
7
28
54
7
5
101
100 -
500
500
and
over
1
2
3
4
5
Total
_
1
2
-
-
3
_
-
-
-
-
0
_
-
3
1
-
4
_
6
5
-
1
12
.
-
1
-
-
1
_
-
1
1
-
2
_
-
1
-
-
1
0
7
13
2
1
23
1
2
3
4
5
Total
Total
_
-
3
-
-
3
32
_
-
-
-
-
0
4
_
-
-
-
-
0
22
_
2
3
1
1
7
57
_
-
-
-
-
0
6
.
-
1
-
-
1
9
_
1
-
-
-
1
6
0
3
7
1
1
12
136
Note: C = Curb
Y = Yard (or House Carryout)
A » Alley
56
-------
TABLE XV
COLLECTION LOCATION
(206 CITIES)
Population, (1,000's)
10 - 100
100 - 500
500 and over
Total
C
A
Y
C&A
Y&A
C&A
C.A&Y
Number of Cities
34
6
2
42
9
1
0
10
26
4
3
33
54
15
8
77
13
5
1
19
8
3
0
11
7
4
3
14
Note: C = Curb
A = Alley
Y = Yard (or House Carryout)
57
-------
TABLE XVI
FREQUENCY OF COLLECTION SERVICE
BY SIZE OF CITY (112 CITIES)
Ul
00
Population
(1,000's)
10 - 100
100 - 500
500 and over
Total
Once Per Week
No. of
Cities
33
10
8
51
Total
Population
1,422,217
2,057,000
5,397,180
8,876,397
Twice Per Week
No. of
Cities
37
11
7
55
Total
Population
1,499,197
2,196,893
4,564,393
8,260,483
Three Times
Per Week
No. of
Cities
2
3
1
6
Total
Population
79,000
452,000
114,000
645 ,000
-------
The slight preference for twice a week collection was primarily in the
cities in the 10,000 or 100,000 population range. However, the per-
centages are similar for cities of all sizes.
7. Lost Time Accidents
A total population of 11,894,787 was represented in
the 80 cities reporting their lost time accident experience (Table
XVII). These cities reported an average annual total of 1,457 accidents.
Based on population served, the incidence of accidents was greatest for
cities in the lowest population range of 10,000 to 100,000; it dropped
in the medium population range of 100,000 to 500,000; and was lowest for
the largest cities with populations of half a million or more. There
was one reported lost time accident per population of 6261 in the smaller
cities, per population of 8439 in the medium size cities, and per popu-
lation of 8988 in the largest cities. No information was supplied con-
cerning man-days lost due to accidents. Although there were fewer
accidents per city for the smaller cities, the larger cities had a lower
accident rate on the basis of population served.
8. Collection Costs
A sample of 166 cities (Table XVIII) reported an annual
total of 12,352,319 tons of solid waste at a cost of $217,040,288, or an
average of $17.66 per ton. This figure, however, was not representative
for any of the three city-size categories. The average collection cost
per ton was $9.50 for cities with populations of less than 100,000,
$10.20 per ton for cities with populations between 100,000 and 500,000,
and $24.05 per ton for cities in the 500,000 and over population range.
The last figure, however, reflected the weighting effect of both the
huge tonnages and high collection costs of one or two large communities.
In order to secure more typical cost figures, the median city in each
population range was determined. The figures for the smaller and medium-
sized cities remained about the same at $9.90 and $10.64 per ton,
respectively; however, the median city in the largest population category
had a collection cost per ton of only $12.78 as compared with the above-
mentioned weighted figure of $24.05. Collection costs reported are
represented by a least squares line in Figure 28.
There were large variations in reported collection costs
per ton among the cities in every population category. Calculations
based on the information submitted ranged from $1.56 to $80.00 per ton.
Some of the more extreme variations were obviously the result of inade-
quate records - or simple clerical errors. Ignoring these extremes,
however, the figures still indicate that wide cost variations are the
rule rather than the exception. It is not uncommon for the refuse col-
lection budgets of two cities in the same state with similar economics,
levels of service, and populations to vary by 200 percent or more. This
would seem to indicate great differences in the cost benefits of different
collection systems. Since labor costs are a significant factor in every
collection budget, an attempt was made to determine the economic effects
of backyard collection service.
59
-------
TABLE XVII
NUMBER OF LOST TIME ACCIDENTS
(80 CITIES)
Population
(1,000's)
10 - 100
100 - 500
500 and over
Total
No. of
Cities
56
18
6
80
Total
Population
2,219,714
3,607,893
6,067,180
11,894,787
Average
Number of
Accidents
Per Year
354.5
427.5
675.0
1,457.0
Population
Per
Accident
6,261
8,439
8,988
8,060
60
-------
TABLE XVIII
ANNUAL SOLID WASTE TONNAGE AND
COLLECTION COSTS (166 CITIES)
Population
(1,000's)
10 -
100
100 -
500
500
and Over
Total
Tons
(Per Annum)
2,813,819
2,803,700
6,734,800
12,352,319
Collection
Cost
($ Per Annum)
26,757,188
28,605,200
161,677,900
217,040,288
Average
Cost
Per Ton
($)
9.50
10.20
24.05
17.66
Cost Per Ton
For
Median City
($)
9.90
10.64
12.78
TABLE XIX
AVERAGE ANNUAL COST PER TON
COMBINED AVERAGES (39 CITIES)
Population (1,000's)
10 - 100
100 - 500
500 and over
Total
Curb side Pickup
Average
Cost Per
Ton ($)
8.61
8.92
20.71
9.52
No. of
Cities
21
6
2
29
Backyard Pickup
Average
Cost Per
Ton ($)
10.71
15.78
14.09
13.08
No. of
Cities
5
4
1
10
61
-------
10,000-
8,000-
6,000-
5,000.
4,000-
Q 3,000
z
00
O 2,000.
i
z"
O
=j 1,000
Q-
2 800-
00
LLJ
u
600
500
400
300
200
100
90
'"
10 15 20
COST PER TON ($)
25
30
FIGURE 28
COST OF REFUSE COLLECTION
IN 46 CITIES
62
-------
For once a week residential collection, the average
reported cost per ton was $8.60 for six cities with curbside collection
and $11.82 per ton for three cities with yard collection service. In
other words, the cost for carryout collection averaged about 37 percent
higher than for curb collection.
In order to enlarge the sample, further analysis
included cities with diversified or unknown weekly collection patterns.
In the enlarged sample of 39 cities, 29 cities reported a total
average collection cost per ton of $9.52 for curbside collection in
contrast with an average cost of $13.08 for 10 cities providing yard
collection. For this larger sample, therefore, the increased time and
labor costs for carryout service were reflected in about a 37 percent
higher collection cost per ton. This indicated that conclusions based
on the smaller sample were substantially correct (Table XIX).
C. Time and Motion Analysis
1. General
As indicated in Section II, Detailed Approach, a theoretical
approach to the comparison of efficiency between one-, two-, and three-
man collection crews was considered important for this study. Although
precautions were taken during conduct of the field surveys to ensure
reasonable comparability, variations in personnel, equipment,and field
conditions did exist, and the data was, therefore, not exactly comparable.
A theoretical approach using industrial time and motion study methods
was undertaken to eliminate the effects of such differences and to verify
the results of the field studies. Comparing the motions required for
the various crews to complete similar tasks, and assigning the appropriate
time values to each human motion required, resulted in closely comparable
time values for collection operations involving alternative crew sizes.
The use of predetermined industrial time standard systems has
grown rapidly in recent years. Their use enables a qualified analyst
to develop time values for alternative methods of performing a job even
though the work task may never have been performed.
"A predetermined time system is an organized body of informa-
tion, procedures, and techniques employed in the study and evaluation of
work elements performed by human power in terms of the method or motions
used, their general and specific nature, and conditions under which they
occur, and the application of prestandardized or predetermined times
which their performance requires."*
MTM (Methods-Time-Measurement) is a system of predetermined
times in common industrial engineering use throughout the world. This
system can be used by the qualified analyst to predict or measure the
time necessary to perform almost any manual task.
*Karger, Delmar W., and H. Bayha Franklin. Engineered Work Measurement.
New York: The Industrial Press, 1959.
63
-------
Each element of a performed task can be measured In a
manner similar to the previously described field studies. However,
when measurement is difficult or the operation exists only as a con-
cept, the analyst need only visualize, carefully list the motions, and
apply the appropriate MTM values to determine the basic expected time
to perform specific refuse collection tasks with different crew sizes.
Comparisons can then be made with the time study values obtained by
actual field studies. The system was used to assign time values to
alternative methods of refuse collection.
The MTM time values are the expected times for a typical,
experienced worker to perform the motions required to complete the work
task under normal conditions.
To determine the MTM time to move an object from one place
to another, it is necessary to determine the length of the move, the
weight of the object moved, the use of one or two hands, the type of
grasping motion, hand motions before or after the move, and other rele-
vant body motions. The associated MTM time for each movement is then
assigned, and the sum of these incremental times is the time for the
object to be moved.
The MTM system does not include time values for factors
which cannot be standardized, such as fatigue, personal and unavoidable
delays. Although developing these latter factors definitively was
beyond the scope of the study, some waste time values were developed
for refuse collection operations; a preliminary evaluation of their
possible effects has been made.
The amount of variation between standard time values developed
for the refuse collection task and any given set of actual field data may
be quite high. Such variations may be due to one or more of the following:
skill of the employee; level of effort; delays; variability within the
task; and other allowances.
The primary cause of the delays will usually be found within
the task itself. For example, the volume and weight of waste per con-
tainer may vary greatly. It is possible for one container to be loaded
to a weight equal to the combined weight of three other partially loaded
refuse containers. When quantities are small, a collector may load two
containers simultaneously. (See Photograph VII) In other cases, he may
have such difficulty with one can that the actual time exceeds the
standard time for two or more cans.
Refuse collectors themselves vary in experience and physical
condition. Skill level is dependent on experience and has a significant
effect on collection time. Motivation is another important variable.
However, when the volume of data is large and adjustments are made for
fatigue and delays, the actual performance times should cluster about
the standard times with no appreciable difference between the MTM and
observed values.
-------
PHOTOGRAPH VII.
COLLECTOR LOADING TWO CANS SIMULTANEOUSLY
65
-------
Weight affects the loading time of each can. Laboratory
tests show that people perform more slowly when moving or carrying
heavy weights. Our standards were based on the assumption that the
refuse collector carried each can with two hands. Approximately 13
percent was added to the normal walking time to estimate the time re-
quired when carrying a loaded container. Similar allowances were made
for other body movements involved in the moving of the loaded containers.
2. Analysis - Time and Motion
Based on motion picture and video tape recordings, a list
was made of the basic human motions required to perform the refuse col-
lection task in the one-, two-, and three-man collection systems, and
the proper MTM values were applied. Where the nature of the process
controlled the time (for example, emptying refuse from the can), field
study time values were used. The basic motion data was formulated into
elements:
a. Dismount from truck.
b. Walk to container location.
c. Grasp and pick up container.
d. Pivot and walk with container to loading location.
e. Dump container contents.
f. Pivot and return with container to storage location.
g. Place container on ground and pivot.
h. Return to cab.
i. Mount truck.
These elements were combined as needed to give expected time
values for the collection of one, two,....10 cans for each of the three
systems under consideration. The data gathered by the field time studies
were compared with the MTM values for the same tasks as a check against
each other.
Alternative collection methodologies, such as backyard col-
lection, collection of both sides of the street with one pass of the
crew, or systems using different equipment types such as right- or
left-hand drive vehicles, can be evaluated by use of the MTM method.
66
-------
3. Results - Time and Motion Analysis
a. Curbside Collection
Figures 29, 30, and 31 illustrate some of the results
of the time and motion analysis. Figure 29 illustrates the standard
time to collect one through ten cans from the curbside location for
one-, two-, and three-man crews. The shape and relative position of
the curves agree reasonably well with the results of the field data
shown in Figure 9. The curves of Figure 29 contain no allowances for
fatigue, personal and unavoidable delays. Figure 30 shows the standard
collection time for disposable containers. As illustrated by comparing
Figure 30 with Figure 29, the time and motion study substantiates that
savings in collection time are possible for any sized crew through the
use of disposable containers.
Figure 31 shows application of the use of HTM values
to a comparison of two alternative equipment types with the side-loading
right-hand drive type used in Municipality A. The figure is intended
to illustrate the effect of driver and loading location on standard
times to collect one through ten cans. Such a plot can be used to
evaluate the economics of purchasing a truck equipped with a right-
hand drive and enables comparison of a rear-loading packer with a
side-loading packer.
For simple collection systems, it may be unnecessary
to determine the values for fatigue, personal and unavoidable delays.
This is particularly true if equipment comparisons are being conducted
within a given system, such as the example just cited. When complex
systems involving different collection methodology and numbers of
personnel are being studied, the possible effect of delays and fatigue
must be considered.
Although the form and relative position of the standard
collection time curves were very similar to the associated field-
measured curves for Municipalities A, B, and C, the difference between
the curves in Figures 9 and 29 prompted a preliminary study to evaluate
fatigue, personal and unavoidable delays. It will be found in Section
D-5 of this report.
b. Backyard Collection
As previously noted, the use of one-man crews has been
limited primarily to the collection of refuse from the curb or alley
location. On the other hand, for backyard collection, the use of three or
more crew members is quite common. As field data were not available for
one- or two-man backyard collection systems, MTM standards for backyard
collection were developed for the three crew sizes used for comparisons.
67
-------
2.0
1.8
1.6
1.4
, _
1 .2
1.0
g 0.8
<
Q
1.
0.4
0.2
ONE-MAN CREW
X
X
x1
X
X
TWO-MAN CREW
THREE-MAN CREW
345
CANS (NUMBER)
FIGURE 29
STANDARD
COLLECTION TIME
CURBSIDE COLLECTION
68
-------
2.0
1.8
1.6
1.4
I'-'
j= 1.0
Q
Qi
<
Q
Z 0.8
0.6
0.4
0.2
0
ONE-MAN CREW
TWO-MAN CREW
THREE-MAN CREW
0 1
3456
DISPOSABLE ITEMS (NUMBER)
FIGURE 30
STANDARD
COLLECTION TIME - DISPOSABLES
CURBSIDE COLLECTION
69
-------
2.0
1.8
1.6
1.4
LLJ
1
'"
1.0
Q 0.8
0.6
0.4
0.2
REAR LOADING
RH DRIVE
SIDE LOADING
RH DRIVE
SIDE LOADING
LH DRIVE
345
CANS (NUMBER)
8
FIGURE 31
EQUIPMENT FACTORS-
STANDARD
COLLECTION TIME
CURBSIDE COLLECTION
70
-------
These evaluations have necessarily been limited due to
the great variety of handling methodologies and operating conditions
possible for backyard collections. In addition, the one-man collection
system is less applicable to backyard collections, and major efforts in
this area were therefore inappropriate under the scope of the contract.
Future studies are needed to define the relative efficiency of backyard
collections using alternative methodologies.
In using MTM to evaluate backyard collection with
different sized crews, difficulty arises in defining the movements of
each member of the crew. In general, both sides of the street are
collected simultaneously, and usually, the truck does not stop in
front of each service. Furthermore, crew members do not necessarily
follow the same repetitive sequence as the collection operation proceeds.
Certain rules were therefore established, and each crew member was
assigned a sequence of houses to service. Additional variables were
the number of containers at each service, the quantity of refuse to be
collected from the rear of each house, and the distance to the storage
location. Shoulder barrels used by crew members are normally capable
of containing the total refuse behind each house. In some systems
observed during field visits, crew members with large-capacity shoulder
barrels served one or more houses on each trip from the truck. The
standards developed, however, assume only one house may be served on each
trip from the truck. Comparisons between the various sized crews on
backyard collection were made on the basis of minutes per collection
stop and man-minutes per service stop. Depending on the crew size, a
collection stop could be composed of two, four, or six houses.
Figures 32 and 33 illustrate the methodology assumed for
the two- and three-man backyard collection operations as defined in the
motion studies. A description of each follows.
The first analysis involves the operation of a conven-
tional rear-loading packer vehicle with a two-man crew: one driver and
one loader (Figure 32). As the equipment proceeds down the street, the
crew collects refuse from homes on both sides of the street. At each
collection stop, four service stops are collected. The loader collects
the two houses on the right side of the truck, and the driver collects
from the two on the left. It is assumed that there is an average of 40
paces, or approximately 100 ft from the truck location to the backyard
locations of the refuse containers. Two cans of refuse are located at
the rear of each house. Both the loader and the driver use shoulder
barrels of sufficient capacity to hold the total contents of the two
cans.
In Method A, illustrated on the left of Figure 32, the
driver must dismount from the cab of the vehicle and complete the same
task as the loader. Under normal conditions, the loader would therefore
complete his task shortly before the driver. Thus, the driver could
control the rate of the system. In the other methods of backyard
71
-------
Direction of
Truck Movement
\
\
\
\
\
X
T
•
METHOD A
Direction of
Truck Movement
METHOD B
LEGEND
(D Loader
(6) Driver
ill Refuse Truck
Residence
Path to Residence by Driver or Loader
Path to Truck by Driver or Loader
No Scale
FIGURE 32
SCHEMATIC
TWO -MAN BACKYARD
REFUSE COLLECTION
72
-------
Direction of
Truck Movement
METHOD A
Direction of
Truck Movement
METHOD B
LEGEND
(LI/ Loader No. 1
@ Loader No. 2
® Driver
2' I Residence
ill Refuse Truck
""" Path to Residence by Loader or Driver
*- Path to Truck by Loader or Driver
No Scale
FIGURE 33
SCHEMATIC
THREE-MAN BACKYARD
REFUSE COLLECTION
73
-------
collection subsequently discussed, one member of the crew usually con-
trols the overall rate of the system. In actual practice, the members
of the crew who arrive back at the truck first may begin walking to the
next series of houses to be collected. In Method A, however, it is
assumed that the loader will wait at the truck for the driver to return,
and then ride on the truck to the next series of four houses to be
collected.
In Method B, the loader and the driver alternate at each
collection stop. At the first collection stop of four houses, the
loader dismounts and collects the refuse from the two houses on the
right; the driver dismounts from the cab of the vehicle and collects
the refuse from the two houses on the left. As previously noted, the
loader will normally return to the truck before the driver. In Method
B, it is assumed that the loader then acts as the driver to the next
stop of four houses. As the operation proceeds, the two crew members
continue to alternate as driver and loader.
The hypothetical three-man backyard collection system
consists of one driver and two loaders (see Figure 33). The following
assumptions are made. Two members of the crew are qualified as drivers,
and the first of these two men returning to the truck acts as the driver
to the next collection stop. At each collection stop of the truck,
refuse is collected from six houses (three on each side of the street),
and each crew man collects two houses. The three men ride on the
vehicle between collection stops. Two cans are collected from the back-
yard of each house, the location of the containers is 100 ft from the
location of the truck, and shoulder barrels are used. Two different
methods were studied for the three-man backyard collection operation
based on the designation of homes to be served by each member of the
crew.
In Method A, referring to the schematic on Figure 33,
Loader 1 dismounts from the right rear of the truck at Point Xj_, and walks
to House No. 1. Loader 2 remains with the truck until it stops at its
location between Houses 2 and 2'. Loader 2 then collects the refuse
from Houses 3' and 3, and rejoins the vehicle at Point X2- The driver
collects Houses 2' and I1, and becomes Loader 1 when the truck proceeds
on to the next collection stop. Loader 1, as indicated on the schematic,
collects from Houses 1 and 2, and becomes the driver to the next stop.
The truck passes at Point X2 for Loader 2 to load the refuse from House
3 into the truck. The system then repeats itself.
In Method B, again referring to Figure 33, Loader 2 and
Loader 1 dismount from the truck at Location Xj_. The driver stops the
truck between Houses 2 and 2', collects the refuse from Houses 3' and 3,
rejoins the truck at Point X2, and becomes Loader 2 for the next col-
lection stop. Loader 1 collects the refuse from Houses 1 and 2, and
Loader 2 collects the refuse from Houses 1' and 2'. Loader 2 becomes
the driver to the next stop. The sequence then repeats itself.
74
-------
In the one-man backyard collection system, it is
assumed that the driver collects from two houses on opposite sides of
the street at each collection stop. All other factors are assumed
the same as for the two-and three-man systems. Table XX summarizes
the results of this phase of the time and motion studies. Although
the time values shown in Table XX are not average times of actual
experience because no allowance is made for fatigue and delays, they
can be used to indicate the relative efficiency of the different methods
investigated. Section D of the report will apply the data in Table XX
to estimate system performance under simulated field conditions.
Referring to the Table, it can be seen that Method B for both the two-
man and three-man backyard collection operations has an advantage over
Method A of about 0.1 man-minutes/house. Under Method B for backyard
collection, both the two-man and three-man crews are more efficient than
the one-man crew, in this simplified analysis. Although the man-minutes/
house for each crew size are nearly equal, ranging from 1.352 rain for
the one-man crew to 1.326 for the three-man crew, the number of service
stops completed in a given time period would be nearly three times
greater for the three-man crew than for the one-man crew. Unlike curb-
side collection, in backyard collection the extra crew members can speed
collections in approximate proportion to their number.
In Section D of the report, the above results have been
incorporated into a mathematical model and projections made of system
cost efficiency including the important effects of haul time, truck size,
and other factors.
c. Refuse Set-Out Systems
In some refuse collection operations in the United States,
a member of the crew sets out refuse from the backyard, and either the
householder or a member of the collection crew returns the empty refuse
containers to their backyard location. It has been determined that the
one-man crew is the most efficient in collecting refuse under normal
curbside collection procedures. It follows that the overall efficiency
of the set-out and set-back, or simply the set-out method of refuse
collection, would be improved when combined with curbside collection if
the one-man crew were used. The number of men needed to set out refuse
from the backyard location to the curb would depend on the quantity of
refuse per service stop and the scheduling necessary to preclude the
collection vehicle's overtaking them. Normally, the set-out operations
would begin prior to the curbside collection operations. Table XX con-
tains the standard time for collection by this method. Further dis-
cussion and projections anpear in Section D.
d. Alley Collection
The use of various sized crews for alley collection has
also been investigated using time and motion analysis methods. The
following describes the basis for these studies. Table XX lists the
respective minutes per collection stop and man-minutes per house for
each method considered.
75
-------
TABLE XX
TIME STANDARDS - ALLEY, BACKYARD,
AND MODIFIED CURBSIDE REFUSE COLLECTION
(2 CONTAINERS/SERVICE STOP)
Method
A(6)
B(^)
B(7)
-
A(S)
B(^)
-(9)
-
B(7)
3(6)
_
fi(7)
s(6)
-
-
No. in Crew
(Including
Driver)
2
2
3
3
1
1
1
2
3
3
2
1
3
2
1
1 + 1
Can
Location
Backyard
Backyard d)
Backyard (3)
Backyard (3)
Backyard ^
Alley
Alley
Alley
Alley
Modified
Curbside(3)
Modified
Curbside(3)
Modified
Curbside(3)
Modified
Curbside
Modified
Curbside
Modified
Curbside
Backyard ^ -
Standard
Time
Min/Stop(-^
2.507
2.381
2.558
2.351
2.403
0.911
0.856
0.490
0.347
1.434
1.340
1.310
2.060
2.110
1.580
0.52
No. of
Services/
Collection
Stop
4
4
6
6
2
2
2
2
2
6
4
2
b
4
2
1
(2)
Man-Min/
Service
Stop
1.402
1.326
1.437
1.332
1.352
0.606
0.578
0.790
0.972
0.867
0.820
0.740
1.180
1.200
0.880
1.42(5)
Notes:
(1)
(2) •
(3) -
(4) -
(5
(6
(7)
(8)
(9)
Standard time per collection stop for both sides of street or
alley with one pass of crew and equipment.
Includes travel time between collection stops on route.
Using shoulder barrels
One man sets refuse at the curb for curbside collection by a
one-man crew.
Includes 0.90 min for set-out operation.
See text and Figure 32 for description.
See text and Figure 33 for description.
See text and Figure 34 for description.
See text and Figure 35 for description.
76
-------
The use of one-man crews for alley refuse collection has
been studied for two different types of equipment: the typical rear-
loading packer, and side-loading equipment which can be loaded from
either side. In each case, the collection of refuse from both sides
of the alley with one pass of the truck is assumed. Figure 34 shows
schematics of the necessary movements for one man using the two differ-
ent types of equipment. A 25-ft alley was assumed in all cases studied.
It will be noted on the schematic that the driver is located on the right
side of the side-loading truck. In 100 percent alley collection, there
would be no difference in the collection time whether the driver was
located on the right or the left side. Most alley collection operations,
however, are performed in conjunction with curbside collection, and there
is a distinct advantage in having the driver located on the right side
for curbside collection. Again, we have assumed for comparative purposes
that there are two cans to be collected from each residence.
The collection of refuse from the alley location by a two-
man crew on a rear-loading packer with the driver and loader alternating
positions at each stop is illustrated schematically in Figure 35. All
other considerations are the same as those in the previous example.
Comparing the columns entitled standard times per collection stop and
the man-minutes per service stop of Table XX indicates that the one-man
crew using either Method A or B is more efficient than the two- or three-
man crew on the basis of man-minutes per service stop. Although the two-
and three-man crews complete each collection stop more rapidly than the
one-man crew, the net man-minutes per service stop is still greater, a
result similar to that found for curbside collections. Projections of
system costs, including equipment and haul will be made for the alley
collection method in Section D.
A final possibility is the use of three-man crews on a
rear-loading packer truck where one man serves as a driver only and
remains in the truck cab. This method has been considered but is not
shown schematically.
e. Modified Curbside Collection of Refuse by One-, Two-,
and Three-Man Crews
In some areas of the country where quiet, narrow resi-
dential streets exist, the curbside collection of both sides of the
street may be possible with one pass of the equipment and crew. The
efficiency of the system depends on street widths, number of containers
per household, vehicular use of the street, and other factors. However,
in the current study, modified curbside collection with alternative crew
sizes and methodology was evaluated assuming two cans of refuse at each
service stop, and a 30 ft street width.
Referring to Figures 32 and 33, observe Method B on the
right of each Figure, but assume that the refuse container is located at
the curb instead of the backyard. The motions of the respective crew
members would be the same as those illustrated and discussed previously,
77
-------
Direction of
Movement
Direction of
Movement
METHOD A
LEGEND
(D) Driver/Loader
0 Refuse Truck
[c] Container Location
»- Path of Movement to Truck or Container
-•—*- Path of Movement for Container Dumping
METHOD B
No Scale
FIGURE 34
SCHEMATIC
ONE-MAN ALLEY
REFUSE COLLECTION
78
-------
STOP
STOP
Direction of
Movement
Alley
LEGEND
O Container Location
© Driver
(D Loader
S Refuse Truck
—»- Path of Movement to Container Location
— -»- Path of Movement for Container Dumping
No Scale
FIGURE 35
SCHEMATIC
TWO-MAN ALLEY
REFUSE COLLECTION
79
-------
except for the curbside location of the refuse. The one-man modified
curbside collection method is also identical to that assumed for the
corresponding backyard collection except for the containers' curb
location.
Two comparisons between the three alternative crew sizes
under the modified curbside collection system were made, one involving
the use of shoulder barrels, the other without shoulder barrels. Results
are shown in Table XX. The slight saving indicated in the use of shoul-
der barrels is contingent upon two cans of refuse at each house and the
crew member transporting only one of these cans on each trip to the
truck without the use of the shoulder barrel. In visits to various
cities, it has been observed that as many as four cans were carried
by a collector at one time.
Although the three-man crew collects from 6 services
at each collection stop compared with 2 services for the one-man crew,
the man-minutes per service stop for the latter is about 25 percent
less than the former when shoulder barrels are not used. A similar
calculation indicates a 14 percent savings for the one-man crew when
shoulder barrels are used, As with the backyard collection method, the
two- and three-man crews complete a given collection route more quickly
than the one-man crew and can therefore make additional service stops.
As a result, equipment requirements are less; however, the collection
labor cost per service stop will be lower for the one-man crew.
Section D further investigates the cost factors involved.
4. Special Analysis
a. Fatigue
As previously observed, the difference between the
"standards" and the field recorded time values are due to delays and
fatigue. Fatigue occurs as the day progresses and also results from
handling a large number of containers at a single collection stop. An
attempt has been made to evaluate both types of fatigue in curbside
collection with some degree of success. The approach for the first type
was as follows: From the field survey data for Municipalities A, B, and
C, the service stops completed early in the day were compared with
similar stops during the later portion of the day. Approximately 150
stops at the beginning and a similar number near the end of the day for
each day of the field surveys were used for the analysis. The final
50 service stops were omitted to reduce the effect of any tendency of
the crew to work faster when the end of the collection day was near.
The data is shown in Figures 36, 37, and 38 for Municipalities A, B,
and C respectively, and is represented by a least squares line in each
case.
Figures 36 through 38 indicate that the one-man crew is
not subject to more fatigue than either the two- or three-man crews.
Factors such as motivation, interrelationships between members of the
80
-------
2.0
1.8
1.6
AGENCY
Municipality A
CREW
SIZE
1
o BEGINNING OF DAY
a END OF DAY
1.4
1.2
D
z
s
LU
0.8
0.6
0.4
0.2
BEGINNING
OF DAY
END
OF DAY
0
0
45678
CANS (NUMBER)
FIGURE 36
FATIGUE ANALYSIS
AVERAGE COLLECTION TIME
PER STOP
81
-------
2.0
1.8
AGENCY
Municipality B
CREW
SIZE
2
1.6
1.4
0 BEGINNING OF DAY
D END OF DAY
1.2
Z. 1.0
LJJ
1 0.8
0.6
0.4
0.2
END OF DAY
BEGINNING OF DAY
345
CANS (NUMBER)
FIGURE 37
FATIGUE ANALYSIS
AVERAGE COLLECTION
TIME PER STOP
82
-------
1.0
1.8
1.6
AGENCY
Municipality C
CREW
SIZE
3
1.4
oo
UJ
° BEGINNING OF DAY
a END OF DAY
1.0
0.8
0.6
0.4
0.2
END OF DAY
EGINNING OF DAY
0
0
345
CANS (NUMBER)
FIGURE 38
FATIGUE ANALYSIS
AVERAGE COLLECTION TIME
PER STOP
83
-------
crew, climatic conditions, and others may have affected the results, but
all Figures indicate that fatigue as measured by the above evaluation
method has a relatively minor influence on the difference between the
standard curves of Figure 29 and the field-recorded values of Figure 9.
Fatigue of the second type was given preliminary
evaluation under separate authorization by the Solid Waste Program.
The physical work necessary to conduct refuse collection operations
was studied, and experiments were conducted to assess the rate of
performance degradation due to certain controllable factors. A
literature search was also conducted and is included in the biblio-
graphy. These studies are preliminary in nature, and further full-
scale human factors investigations of collection operations are re-
quired for a comprehensive definition of relationships.
The purpose of the human factors experiment was to
evaluate the degradation in performance resulting from loading height
and container (plus contents) weight. The loading heights used were
30 in., 42 in., and 48 in. Weights of containers plus contents were
45 Ib, 60 Ib, and 75 Ib. Many municipalities limit allowable weights
of containers plus contents to the 50 to 80 Ib range. In practice,
few containers actually contain the maximum weight, and the average
weight per container is considerably less than the 45 Ib minimum used
in the experiment.
The experiment was conducted over a month and a half
period at the company's laboratory. Photographs VIII, IX, X and XI
illustrate the experimental monitoring equipment set-up, and the test
subject during one test run. Continuous monitoring of the experiment
for later review and study was made using the video unit shown. Burlap
sacks were filled to the proper weight with discarded golf balls from
a nearby driving range. A metal stand was fabricated to adjust the
loading height. At least two refuse containers (conventional 32 gal
galvanized) were used in each experimental test run. While one can
was being lifted and emptied, the other was reloaded for the next lift
motion. Two men were stationed adjacent to the adjustable loading
height bar to replace the emptied contents into the empty can set
down by the subject. A fourth man recorded the number of containers
loaded and the elapsed time for selected groups of containers. A
copy of the data form is included in Appendix E.
Initially, four subjects volunteered to participate in
the study. Each was a student at a nearby university, between the ages
of 20 and 22. The height, weight, and age of each subject is recorded
in Table XXI. Subjects 1 and 2 were forced to drop out of the study
due to illness and work requirements. The remaining subjects completed
the experiment.
During the initial stages of the experiment, pilot
studies were made to establish suitable experimental procedures for
handling refuse containers, contents, and timing procedures, and to
84
-------
PHOTOGRAPH VIII.
VIDEO TAPE MONITORING EQUIPMENT
PHOTOGRAPH IX.
VIEW FROM VIDEO MONITOR
PHOTOGRAPH X.
EXPERIMENT IN PROGRESS
PHOTOGRAPH XI.
DATA RECORDING
85
-------
TABLE XXI
HUMAN FACTORS EXPERIMENT
PHYSICAL DATA - SUBJECTS
Subject
1
2
3
4
Age
22
21
21
20
Height
6' 2"
6'0"
6'1"
5 '9"
Weight (Lb)
180
160
170
200
86
-------
establish three simulated loading heights and weights for use throughout
the study. Initially, subjects were instructed to start loading the
cans' contents and to continue until the incremental time per can
increased significantly over the initial loading rate. This method
was found unsatisfactory because the subject would soon establish a
pace for himself and continue the simulated loading operation for
extended periods.
In order to use heights and weights reasonably close to
those experienced in practice and concurrently obtain significant amounts
of performance degradation, it was necessary to vary the procedure. The
subjects were therefore instructed to load as rapidly as possible and to
load until unable to continue or the data indicated rapid degradation.
The results of these tests are presented in Table XXII. All subjects
were of about average stature, ranging from 160 to 200 Ib in weight and
had no previous experience with loading refuse. Subject 1 performed at
an average rate of 0.04 HP, Subject 2 at a rate of 0.02 HP, Subject 3 at
an average rate of 0.05 HP, and Subject 4 at an average rate of 0.04 HP,
during these pilot studies. Since the literature indicates that man may
perform over extended periods at a 0.05 HP rate, the subjects were well
within the accepted work rate level.
Opposition to the use of fewer men on collection vehicles
is frequently based on the assumption that there is too much work for one
man. The test subjects, however, were capable of simulating the loading
of more tonnage in a period of one to two hours than most collection crews,
regardless of the number in the crew, load during the entire time on the
route. Route time normally totals some four hours in an efficient collec-
tion system.
Furthermore, one-man crews observed in Municipality A
consistently loaded eight or more tons per day from the curbside location,
and many one-man crews loaded from 10 to 12 tons per day. These crews
experienced minimal amounts of overtime, usually because of the necessity
to return to collect a partial load during heavy refuse generation periods.
The use of the video TV tape recording equipment was
very helpful. Appendix F discusses the advantages and disadvantages
of using video TV during human factor studies.
Each combination of loading height and container weight
was repeated three times for each subject during the experiment. A
random number table was used to assign a loading height and container
weight for each subject for each day of the experiment.
Statistical methods were used to analyze the experimental
test results. From the data, the average time to load the next container
was calculated following the cumulative loading of 1000, 3000, and
5000 Ib of refuse. The average was made up of six readings in each
case. The data was placed in a 3 x 3 matrix for convenient analysis.
Each matrix is illustrated below. The values within each matrix represent
87
-------
the average time in seconds to load the container with the indicated
height and weight, following the cumulative loading of 1000, 3000, or
5000 Ib respectively.
75
Container 60
Weight (Lb)
45
1000 Lb
Loading Height (In.)
48 42 30
5.6
4.3
2.7
4.9
4.4
3.4
4.7
4.6
2.9
75
Container
Weight (Lb) 60
45
48
3000 Lb
Loading Height (In.)
42
30
6.2
4.7
3.1
5.4
5.2
4.4
5.2
4.9
3.2
75
Container
Weight (Lb) 60
45
48
5000 Lb
Loading Height (In.)
42
30
7.1
5.2
3.5
6.1
6.4
5.4
5.8
5.2
3.6
The data is illustrated graphically in Figure 39.
88
-------
TABLE XXII
HUMAN FACTORS EXPERIMENT
SUMMARY OF RESULTS - PILOT STUDY
Subject
Can +
Contents
Weight
(Lb)
Loading
Height
(In.)
Total
Elapsed
Time
(Min)
Average
Loading
Time /Can
(Sec)
Beginning
End
Total
Cans
Loaded
Total Weight
Loaded
(Tons)
1
30
24
110
3.75
6.00
1020
15.3
2
75
48
30
7.00
20.00
155
5.8
2
45
30
53
4.37
7.60
600
13.5
2
75
30
50
6.00
10.00
320
12.0
3
60
42
30
4.00
13.00
240
7.2
3
45
42
29
4.50
8.80
280
6.3
4
60
30
31
6.00
12.00
210
6.3
4
75
48
28
10.10
12.00
170
6.4
89
-------
10
a 6
O
U
UJ
LO
~ 5
LU 4
Q_
LEGEND
Symbol Container Weight (Lb)
r*^«_, 60
75
Loading Height (In.)
A
D
O
30
42
48
^" yZ*S*1Sr
42" vzzZ3*"*
*5**&*:zz~
^^^ °&.**'^~r
"^~~'*'"^^**~'
•••r'*^ —n^^^ .j^
--^
^r«
42"
48"
,>,«^
42"
30"
tCT«o
*«»"•
48"
1000 2000 3000 4000
CUMULATIVE REFUSE LOADED (Lb)
5000
FIGURE 39
HUMAN FACTORS
EXPERIMENTAL DATA
90
-------
The analysis of variance method permits us to determine
whether the performance degradation is due to the height of the bar or
to the container weight.
Using the above data, statistical tests at the 5 percent
level of significance indicate that the total weight of the filled con-
tainer and contents was a positive factor in the degradation of perform-
ance, and that the addition of each 10 Ib increment to the container
weight between 45 and 75 Ib resulted in an additional 0.7 sec loading
time per can. This increase was reasonably constant whether the cumula-
tive quantity previously loaded was 1000 Ib, 3000 Ib, or 5000 Ib.
Although the differences in performance between 45-lb and
60-lb containers, and between 45-lb and 75-lb containers, were significant
at the 5 percent level, those between 60 and 75-lb containers were not.
The effect of loading height on performance degradation was not signifi-
cant.
Although the results are preliminary, they indicate that
fatigue had little effect on the relative effiiciency of either the one-,
two-, or three-man crew; the work load associated with use of the one-man
crew was not excessive; and the combined weight of the refuse container
and its contents was a more important factor in performance degradation
than the loading height of the vehicle.
b. Delays
Video TV films of field collection operations in Munici-
palities A, B, and C were obtained and given detailed study. Using slow
motion, instances of personal and unavoidable delays were extracted, and
respective times for each type of delay were recorded along with the
number of containers at the stop. The video tape equipment was valuable
for this analysis as the tapes could be rerun, stopped, and operated in
slow motion as required.
The video tapes revealed several different types of
delays: the most common unavoidable delays resulted from removal of lids
from refuse containers prior to loading and the operation of the truck's
packer mechanism at a collection stop. The three municipalities used
packer vehicles equipped with auxiliary engines so that the packing
operation could normally be conducted while the vehicle was traveling
between collection stops. However, at stops with large quantities of
refuse or when the load was nearly full, it was often necessary to
operate the packer while at the collection stop. Other delays were
caused by cars parked adjacent to the container location, arid the
spilling of refuse from the hopper during packing or from the container
while loading. Personal delays involved lighting a cigarette, conversa-
tion, interferences between members of the two- or three-man crew, and
other incidents. Table XXIII lists the types of delays experienced in each
of the municipalities along with the average lost time per occurrence and
per service stop.
91
-------
TABLE XXIII
DELAYS
MUNICIPALITY A
No.
1
2
3
4
5
6
7
8
Type of
Delay
Packer
Parked cars
Pick up
spill
Lids
Difficulty
in emptying
cans
Scavenging
Talk
Wait, adjust
gloves, etc.
Number
of
Occurrences
150
22
13
159
5
-
2
8
Total Lost
Time
(Min)
15.51
2.48
0.58
2.74
0.35
-
0.21
2.06
Average
Lost Time/
Occurrence
(Min)
0.103
0.113
0.045
0.018
0.07
-
0.105
0.257
Average
Lost Time/
Stop
(Min)
0.120
0.019
0.004
0.021
0.003
-
0.002
0.016
Total Number Service Stops Studied: 129
92
-------
TABLE XXIII
(Continued)
DELAYS
MUNICIPALITY B
No.
1
2
3
4
5
6
7
8
Type of
Delay
Packer
Parked cars
Pick up
spill
Lids
Difficulty
in emptying
cans
Scavenging
Talk
Wait, adjust
gloves, etc.
Number
of
Occurrences
63
20
16
46
47
1
9
8
Total Lost
Time
(Min)
7.94
2.24
2.33
0.79
3.65
0.53
3.49
8.40
Average
Lost Time/
Occurrence
(Min)
0.132
0.112
0.146
0.017
0.078
0.53
0.388
1.05
Average
Lost Time/
Stop
(Min)
0.066
0.019
0.019
0.007
0.030
0.004
0.029
0.070
Total Number Service Stops Studied: 120
93
-------
TABLE XXIII
(Continued)
DELAYS
MUNICIPALITY C
No.
1
2
3
4
5
6
7
8
Type of
Delay
Packer
Parked cars
Pick up
spill
Lids
Difficulty
in emptying
cans
Scavenging
Talk
Wait, adjust
gloves, etc.
Number
of
Occurrences
60
13
17
8
30
31
9
20
Total Lost
Time
(Min)
4.59
1.45
0.94
0.12
2.44
4.10
0.91
2.34
Average
Lost Time/
Occurrence
(Min)
0.076
0.112
0.055
0.015
0.081
0.132
0.101
0.117
Average
Lost Time/
Stop
(Min)
0.043
0.014
0.009
0.001
0.023
0.039
0.009
0.022
Total Number Service Stops Studied: 106
-------
The analysis of personal and unavoidable delays is
illustrated in Figures 40, 41, and 42 for Municipalities A, B, and C,
respectively. These figures indicate the mean collection time for
service stops composed of from one through five cans based on the de-
tailed field surveys, and the adjusted standard times for collecting
similar stops based on the MTM values plus the personal and unavoidable
delays just described. The close correlation between the two sets of
data for each municipality is apparent.
Because the mean collection time for the field survey
data was calculated on the basis of all field collection time values,
it does include a fatigue factor. However, the previously described
fatigue studies indicate that it probably plays a relatively minor role
in the differences between MTM-developed collection times and those
actually recorded during the field surveys.
The close agreement between the field-measured collection
times and the MTM standard times adjusted for unavoidable and personal
delays indicates the MTM values are applicable to refuse collection
analysis and provide a convenient means for estimating efficiency of
one-, two-, and three-man collection crews. In addition, it indicates
that the municipalities and crews chosen for the detailed field surveys
were closely comparable and that conclusions derived from the field
studies are substantially valid.
D. Mathematical Model
1. General
A mathematical model may be defined as a mathematical formu-
la which describes the interrelationships between variables affecting a
giyen system. If a model can be formulated to describe a system, com-
puters can be used to simulate system operation and performance when
variables are assigned numerical values.
A limited model was developed describing the time required
for the collection of refuse. The purpose of the model was to enable
projections of refuse collection system performance for alternative crew
sizes, collection methodologies, truck sizes, haul distances, and labor
and equipment costs. The following factors which affect the efficiency
of collection were included in the model:
a. Mean quantity of refuse per collection stop.
b. Driving time between the route and the disposal site.
c. Mean collection time at each collection stop and
travel time to the next stop.
95
-------
2.0
1.8
AGENCY
Municipality A
CREW
SIZE
1
1.6
1.4
0 ADJUSTED STANDARD
D FIELD SURVEYS
1.2
i '•"
0.8
0:6
0.4
0,2
ADJUSTED
STANDARD
FIELD
SURVEYS
345
CANS (NUMBER)
8
FIGURE 40
COMPARISON
AVERAGE COLLECTION TIME
FIELD - ADJUSTED STANDARD
96
-------
2.0
1.8
AGENCY
Municipality B
CREW
SIZE
2
1.6
1.4
o ADJUSTED STANDARD
° FIELD SURVEYS
1.2
LJLJ
2 K0
I
uj 0.8
^
i-
0.6
0.4
0.2
FIELD
SURVEYS
ADJUSTED
STANDARD
345
CANS (NUMBER)
7
8
FIGURE 41
COMPARISON
AVERAGE COLLECTION TIME
FIELD-ADJUSTED STANDARD
97
-------
2.0
1.8
1.6
AGENCY
Municipality C
CREW
SIZE
3
1.4
1.2
o ADJUSTED STANDARD
a FIELD SURVEYS
z i.o
i 0.8
0.6
0.4
a. 2
FIELD —
SURVEYS
ADJUSTED STANDARD
0
345
CANS (NUMBER)
FIGURE 42
COMPARISON
AVERAGE COLLECTION TIME
FIELD-ADJUSTED STANDARD
98
-------
d. Total non-productive time including: travel time
between the yard and the route and between the disposal
site and the yard; relief, lunch, and dispatch time;
and incidential time losses resulting from road condi-
tions, equipment breakdown, etc.
e. Mean disposal time per load at the disposal site.
To optimize a refuse collection system, it is necessary to
minimize the total collection cost per unit of refuse collected. The
combination of truck volume and crew size which satisfies the above
criterion is the optimum for any given set of conditions.
In the study of field factors described subsequently in
greater detail, the factors vary greatly. Ideally, the actual statis-
tical distributions of each should be determined. However, this would
complicate calculation of the model and the simulation could not be
readily completed by the small desk-type electronic computer used in
this study. The contract scope of work did not include large-scale
simulation on a wide-range large-capacity electronic computer. A
stochastic program with all the field factors considered can give
much better and more accurate results, but it would require more data
preparation and a larger computer for analysis.
Some assumptions were necessary in the model. Where possible,
these assumptions were based on field experience and survey data. Dis-
crete values were used in the model; however, a range of those considered
most important was used. The model calculations thus are approximations
of the true field conditions.
2. Basic Assumptions
a. The average number of cans per service stop is three,
and the corresponding times required per collection stop
for curbside collection are:
(1) One-man crew: 0.60 minutes
(2) Two-man crew: 0.54 minutes
(3) Three-man crew: 0.46 minutes
These values were based on field data from Municipalities
A, B, and C, as verified by the MTM values. Because much of the
simulation work was completed prior to the final field surveys in
Municipalities A, B, and C, the above time values were based on
only the summer and winter survey data. There are only minor differences,
however, between these values and those compiled following the inclusion
of data from the field surveys.
99
-------
Table XX lists collection stop time values used for
simulation of backyard, alley, and modified curbside collections.
b. The average time of travel between stops is 0.17 minutes
based on field data. Correspondingly higher values were
used for collection stops composed of four and six
services.
c. The minimum partial load to be collected is one-eighth
the volumetric capacity of the truck.
d. There is no limit to the allowable number of trips within
the working day, and any total amount of refuse may be
collected by the crew.
e. The normal work day is 480 minutes, with a maximum allow-
able overtime of 30 minutes.
f. The crew is paid for a minimum of eight hours; if they
finish the assignment earlier, they are relieved.
g. The labor rate for overtime is 1.5 times the normal rate.
h. The truck operating cost is linearly proportioned to the
capacity of the truck. The cost of the truck time during
relief time taken by the crew is assumed to be half that
during haul time. The assumed costs of various truck
sizes are shown in Table XXIV.
i. Labor is available at 8 cents per man-minute, or $4.80
per hour (including fringe benefits). There is no cost
differential between driver and loader.
j. Mean time per load at the disposal site is 10 minutes.
k. The mean density of the refuse following compaction in
the vehicle is 550 lb per cu yd.
3. Symbols
a: The ratio of weight of refuse collected to the weight
capacity of the collection vehicle.
B: One-way average driving time between the route and the
disposal site (min).
C: Total cost per ton for labor and equipment ($/ton).
CS: Crew size (including driver).
100
-------
TABLE XXIV
COSTS OF VEHICLE TIME
EQUIPMENT COST ONLY
Truck
Size
Collection
Time
i-l 4)
3 e
n) -H
as H
Relief
Time
12 Cu Yd
$3.75/Hr
6.25c/Min
$4.00/Hr
6.67c/Min
$2.00/Hr
3.33
-------
CV: Total vehicle cost ($/day).
D: Mean disposal time (min/load).
d: Mean density of refuse in the vehicle (Ib/cu yd).
E: Total on-route collection time (min).
e: Vehicle cost during collection ($/min).
H: Total haul time; includes driving between stops on route,
to and from disposal site, yard to route, and disposal
site to yard (min).
h: Vehicle cost during haul ($/min).
K: Total non-productive time (min); includes dispatch,
lunch and relief, yard to route time, and disposal
site to yard time.
LC: Labor cost ($/ton).
LR: Labor rate on straight time ($/min).
Lj: Total labor time at straight time (min).
MJJ : Paid man-minutes per ton (min/ton).
Q: Mean quantity of refuse per collection stop (Ib).
R: Total relief time (min).
r: Vehicle cost while not in operation ($/min).
S: Service stops per load (number/load).
SC: Service stops completed (number/day).
t: Mean time per collection stop plus travel time to the
next stop (min).
T: Total refuse collection (tons).
V: Vehicle volumetric capacity (cu yd).
VH: Vehicle time per ton (min/ton).
Vc: Vehicle cost ($/ton).
X: Total time to make n trips, or to collect and dispose
of N loads (min)-
102
-------
4. Formulation
The various values to be tabulated were calculated as follows:
Total time to complete one trip (collect one full load):
X, = Vtd + B + K + D
1 ~~Q~
At the disposal site, the following apply:
if X-^ > 480, there may be only one trip for the day.
if Xi + 2B + D >510, there may be only one trip for
the day-
if Xi > 510, the following calculation is made:
510 = a Vtd + B + K + D; solving for a gives us
Q
the fraction of the truck capacity filled or the
partial load size.
if X, + 2B + D < 510 and ^ < 480, the truck may be
sent for a second or more loads as the time permits.
The truck goes for a total of n trips, where:
Xn + (n + a - 1) Vtd + (2n - 1) B + K + nD
Q
if Xn < 510 < Xjj+i for a > 1/8
if a < 1/8, only (n - 1) trips are made.
Now:
N = (n + a - 1)
T = NVd
2000
SC = NVd
LT = 480 (CS) if ^ < 480, or
= CS {1.5 (^ - 480) + 480)} if Xn > 480
103
-------
VH - ^n
T
Lc - MR
CV - H (h) + E (e) + R (r)
Vc = CV
T
5. Results - Mathematical Model
The model has been used to simulate the refuse collection
operation with chosen values for the model variables. The results of
the many simulations are shown in Figures 43 through 73. Most of
the simulation work was conducted to compare one-, two-, and three-
man collection crews for curbside collection. However, a few
simulations were completed for backyard, alley, and modified curbside
collection methods.
On each figure, the abscissa represents the volumetric
capacity of the refuse collection vehicle. Figures 43, 44, and 45
compare the unit cost per ton for collection and haul of the three crew
sizes for a range of representative values of K, B, and Q, where:
K • total non-productive time (min); Includes dispatch,
lunch and relief, yard to route time, and disposal site
to yard time.
B - one-way average driving time between the route
and the disposal site (min).
Q - mean quantity of refuse per service stop (Ib).
Referring to Figures 43, 44, and 45, the following observa-
tions can be made. The one-man operation is less costly than either the
two- or three-man crew, regardless of truck size and over the full range
chosen for K, B, and Q. As K and B become smaller, the cost differential
between crews and the effect of truck size on cost also become less. Unit
costs generally decrease as equipment volumetric capacity is increased;
partial loads, however, cause instances of increased cost with larger
equipment.
104
-------
25
20
K - 50
B = 10
Q =100
CS = Crew Size
Z
o
LLJ
O.
§,0
U
*~ •«. ~&
n
U
i i i i I i i i i I i i i i I i i i i I i i i
10
15
_
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
FIGURE 43
TOTAL COST CURVES
CREW COMPARISON
105
-------
z
o
LU
a.
O
u
K =100
B = 30
Q = 75
0
15
20 25 30 35 40
VOLUME OF TRUCK (CU YD)
.FIGURE 44
TOTAL COST CURVES
CREW COMPARISON
106
-------
25
20
15
K = 175
B = 50
Q= 50
Z
o
C£
LLJ
1/5
O
u
CS = 2, t =
0.71
10
0.77
0.
i i i i
I L
0
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
FIGURE 45
TOTAL COST CURVES
CREW COMPARISON
107
-------
Figures 46, 47, and 48 were constructed from Figures 43,
44, and 45, and illustrate the range in unit cost per ton for each crew
size. The chosen values for K, B, and Q represent probable extremes in
any curbside collection operation in the United States. These results
serve as an estimate of the reduced collection costs possible through
the use of the one-man crew for curbside refuse collection under the
field conditions assumed in the model. The differences in unit costs
become increasingly important as haul time (B) and non-productive time
(K) increase.
Figures 49, 50, and 51 compare the number of services col-
lected by each of the three crew sizes. Generally, the use of larger
vehicles enables the collection of more services by each crew because
with fewer trips to the disposal site a greater portion of the collection
day is spent on the route. The ability of the two- and three-man crews
to collect a greater number of services per day reduces the total equip-
ment requirements for the refuse collection operation, thereby reducing
total equipment costs. However, in the above described cost calculations,
reduced equipment costs are more than offset by the increased labor costs
of the multi-man crews. In many collection operations, particularly
those of municipalities, crews are required to collect a fixed number of
services each day. Figures 49, 50, and 51 can be used to estimate the
number of crews required for operations using different equipment capa-
cities.
Figures 52, 53, and 54 illustrate for each crew size the
range in services collected based on the chosen variations in (K), (B),
and (Q).
The average cost per service for refuse collection is impor-
tant to the operations manager and to the resident. Figures 55, 56, and
57 compare the average cost per service for the three crew sizes and
demonstrate the potential value of the one-man crew in reducing collec-
tion costs.
Figures 58, 59, and 60 illustrate the effect of varying the
value of (Q) on the number of services collected. As the mean quantity
of refuse per service increases, the crew must use a larger truck to
collect the same number of services per day. Although (Q) was varied
from 50 to 100 Ib, the model simulation assumed that in each instance
three containers were placed for collection; thus (t) did not vary with
(Q). In practice, an increase in (Q) would probably result in an increase
in the average number of containers per service, and consequently, the
(t) value. This would cause the curves on each figure to spread further
apart. The curves developed, however, indicate the general relationship
between the quantity of refuse per stop, haul and non-productive time,
truck volume required to complete a given number of service stops, crew
size, and costs.
108
-------
25
20
15
Z
o
LU
Q_
u 10
K = 175
B = 50
Q= 50
= 0.77
K = 100
B = 30
Q= 75
t = 0.77
K =
B =
Q =
t =
50
10
100
0.77
0
i i i i
i i i i
I I
10
15
20
25
30
35
40
VOLUME OF TRUCK (CU YD)
109
FIGURE 46
TOTAL COST CURVES
RANGE, ONE-MAN CREW
-------
K - 175
B - 50
Q= 50
= 0.71
K = 100
B = 30
Q= 75
= 0.71
K = 50
B = 10
Q = 100
t -0.71
9 L...L...__L..J. -I ,__i _
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
110
FIGURE 47
TOTAL COST CURVES
RANGE, TWO-MAN CREW
-------
25
20
K = 175
B = 50
Q= 50
t = 0.63
15
Z
o
UJ
Q.
I—
LTl
O
\
\
K = 100
B = 30
Q= 75
t = 0.63
K = 50
B = 10
Q =100
t-0.63
01 i i i i I i i i i I i i i I I i i i i I i i i i I i i i I | i I
10 15 20 25 30 35 40
VOLUME OF TRUCK (CU YD)
111
FIGURE 48
TOTAL COST CURVES
RANGE, THREE-MAN CREW
-------
K = 50
B = 10
Q = 100
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
FIGURE 49
AVERAGE SERVICES COLLECTED PER CREW
CREW COMPARISON
112
-------
K= 100
B = 30
Q= 75
100
0
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
113
FIGURE 50
AVERAGE SERVICES COLLECTED PER CREW
CREW COMPARISON
-------
Q= 50
CS = Crew Size
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
FIGURES!
AVERAGE SERVICES COLLECTED PER CREW
CREW COMPARISON
114
-------
800
700
S 600
CO
D
z
tt 500
K = 50, B= 10
Q = 100, t = 0.77
o
u
400
300
200
K = 200, B = 30
_Q = 75, t = 0.77.
y^ K = 175, B = 50
Q = 50, t = 0.77
•••••*•
100 ri i i i
i iii i i i i i i i i i i i i i i i i i i
0
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
115
FIGURE 52
RANGE IN SERVICES
COLLECTED PER CREW
ONE-MAN CREW
-------
800
700
600
ID
z
Q
LLJ
I—
u
8
00
LU
y
^
LU
K = 50, B= 10
1 Q = 100, t = 0.71
K = 100, B = 30
= 75, t = 0.71
= 175, B = 50
= 50, t = 0.7T
100 r i i i i i i i i i i i i i
20 25 30 35
VOLUME OF TRUCK (CU YD)
116
FIGURE 53
RANGE IN SERVICES
COLLECTED PER CREW
TWO-MAN CREW
-------
D
z
LLJ
o
u
to
LLJ
U
UJ
1/-J
K = 50, B= 10
Q = 100, t = 0.63
K= 100, b = 30
Q = 75, t = 0.63
= 175, B = 50
Q = 50, t = 0..63
1QQh i i i
' ' ' ' ' '
200
VOLUME OF TRUCK (CU YD)
117
FIGURE 54
RANGE IN SERVICES
COLLECTED PER CREW
THREE-MAN CREW
-------
0.7Q-
0.60
K =50
B = 10
Q = 100
CS = Crew Size
0.50
0.40
co
o
U
CS = 3
t =0.63
0.30
0,20
CS = 2
•VhJ: = 0.
CS =
71
t= 0.77
10
15
_L_L_L_L
30
I I I I
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
118
FIGURE 55
COST PER SERVICE
CREW COMPARISON
-------
0.70
0.60
0.50
0.4C
o
u
0.30 —
0.20
K =100
B = 30
Q= 75
CS = Crew Size
10
15
30 35
VOLUME OF TRUCK(CU YD)
40
119
FIGURE 56
COST PER SERVICE
CREW COMPARISON
-------
0.70
0.60
K = 175
B = 50
50
CS = Crew Size
0.10 L_l
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
FIGURE 57
COST PER SERVICE
CREW COMPARISON
120
-------
800
700
K= 50
B = 10
t - 0.77
S
CQ
2
z
uu
\j 500
O
u
on
LU
y
£400
uj
00
300
200
lOOh
10"
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
FIGURE 58
AVERAGE SERVICES COLLECTED PER CREW
121 ONE-MAN CREW
-------
800
700
2 600
CO
Q
g 500
O
u
U
> 400
300
200
100 hi i i i I i
10
K= 50
B = 10
t =0.71
15 20 25 30
VOLUME OF TRUCK (CU YD)
35
40
FIGURE 59
AVERAGE SERVICES COLLECTED PER CREW
TWO-MAN CREW
122
-------
800
K= 50
B = 10
t = 0.63
100 r i i i i I i i i i i i i
i i i i i i i i
LJ I I I
40
VOLUME OF TRUCK (CU YD)
FIGURE 60
AVERAGE SERVICES COLLECTED PER CREW
THREE-MAN CREW
123
-------
The assumption that the crews collect refuse as long as time
permits, regardless of the number of services collected, is an ideal
situation. Most refuse collection operations have a fixed number of
services which must be collected each day or within a given period, and
several calculations were made in which the total number of services to
be collected was assumed to be fixed. The number of crews necessary
for collection of these services was calculated for different truck
sizes. In small systems involving less than 5000 service stops, the
average cost per ton for all crews varied less than 10 percent from the
values presented on the figures. As the number of service stops in-
creased to 100,000, the difference dropped to less than 3 percent.
Irregularities in the total cost curves are mainly due to
the collection of partial loads and the occurrence of overtime. The
return to collect a small partial load, particularly where the haul time,
B, is large, may be quite expensive on a unit cost basis. The model
restricted partial loads to those greater than one-eighth of a full load
in an attempt to reduce their effect on costs. Refuse collected on
overtime costs more per unit of refuse than that collected on regular
time. However, once a truck and crew are on the route collecting refuse,
if the truck has remaining capacity to collect an additional quantity,
it is more economical to let that crew continue to collect overtime
than to schedule an additional truck and crew for a full day's operations,
unless the additional refuse is sufficient to keep the crew active for
most of the day.
Referring again to Figures 49, 50, and 51, it can be seen
that the number of services collected varies both with crew size and
truck volume. The number of services collected may remain constant,
increase, or decrease with increasing truck volume. The services col-
lected remain constant when two different sized trucks each complete a
510 minute day with one full load and a partial second load. Although
the final partial load is larger in the smaller truck, since each truck
has spent an equal time collecting, the number of services collected is
the same. The number of services may decrease with a larger truck
because after collectin one or more full loads, there may not be
sufficient time to collect the minimum one-eighth partial load of the
larger truck, whereas the smaller truck may be able to collect refuse
for the full 510 minute day.
As previously noted, the model was used to simulate backyard,
alley, modified curbside, and set-out systems of collection using the
time standards presented in Table XX. The simulations were based on one
set of input data, and the results are only an indication of the existing
relationships. Figures 61 through 66 illustrate the unit costs and ser-
vices collected by one-, two-, and three-man crews for backyard, alley,
and modified curbside collections. Figures 61 and 62 indicate the
inefficiency of the one-man crew for use in backyard collections. The
three-man crew has an advantage over both the one- and two-man crews for
backyard collection. Figures 63 and 64 indicate that the one-man crew
is more efficient for alley collections. The trend of the total cost
curves of Figure 63 indicates, however, that the advantage may disappear
when larger trucks are used in conjunction with short haul distances.
124
-------
15.00
to-
K= 100
B= 10
Q= 50
CS = 3 f = 3.24
10.00 I I I I I I I I I I I I I I I I I I I I I ! 1 I 1 L
VOLUME OF TRUCK (CU YD)
125
FIGURE 61
TOTAL COST PER TON
BACKYARD COLLECTION
-------
B = 10
K = 100
Q= 50
CS = Crew Size
20 25 30
VOLUME OF TRUCK (CU YD)
126
FIGURE 62
SERVICES COLLECTED
BACKYARD COLLECTION
-------
8.00
•t/s-
K - 100
B - 10
Q= 50
CS =* Crew Size
TWO SERVICES
PER COLLECTION STOP
t=0.78
5.50 i i i i I I i i i I I LJ
I I I I I I I I .1 I I
30 35 40
VOLUME OF TRUCK (CU YD)
127
FIGURE 63
TOTAL COST PER TON
ALLEY COLLECTION
-------
1350
K = 100
B = 10
Q = 50
CS = Crew Size
TWO SERVICES
PER COLLECTION STOP
450
20 25 30 35
VOLUME OF TRUCK (CU YD)
128
FIGURE 64
SERVICES COLLECTED
ALLEY COLLECTION
-------
20
K - 125
B = 30
Q= 50
CS = Crew Size-
15
Z
o
(XL
UJ
O_
J—
LO
O
u
10
(6 Cervices/coI lection stop)
CS = 1
I— t=l,81
(2 services/collection
_ stop)
(4 services/eol lection stop)
i i i
i i
10
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
129
FIGURE 65
TOTAL COST PER TON
MODIFIED CURBSIDE COLLECTION
SHOULDER BARREL - METHOD A
-------
K =125
B = 30
Q= 50
CS = Crew Size
CS =
t = 2.09
(6 services/col lee
Hon stop)
CS- 2
- 1.98
(4 services/collection stop)
t = 1.81
(2, services/col lee
Hon stop)
20 25 30
VOLUME OF TRUCK (CU YD)
FIGURE 66
AVERAGE SERVICES COLLECTED PER CREW
MODIFIED
130 CURBSIDE COLLECTION
SHOULDER BARREL - METHOD A
-------
For modified curbside collection under the conditions
assumed, the one-man crew loses its economic advantage as a result
of the multiple collections by each crew member. Figure 65 indicates
that the three systems are almost equal in terms of cost per ton of
refuse collected. As haul distances and the total value of non-
productive time increase, the one-man crew could be expected to become
more efficient for modified curbside collection than either the two-
or three-man crew, but the advantage would be less than with curbside
or alley collection. Figure 67 illustrates the cost per ton for an
assumed backyard set out system.
The curves on Figures 68 to 73 were developed using the
previously described mathematical model with the Identical rules and
cost relationships; however, the time per service stop for curbside
collection has been assumed to conform to commonly used system design
data. These values for the time per stop assume that the two-man and
three-man crews are respectively one-third and two-thirds faster per
service stop than the one-man crew.
The general form and relative position of the one-, two-,
and three-man curves on these figures have little similarity to the
curves for curbside collection based on the report data. As the time per
stop values developed in this report are based on significant amounts
of detailed field study and were verified by industrial engineering time
and motion analyses, the above-mentioned system design values appear
erroneous, and their further use does not seem warranted.
6. Nomographs
A series of nomographs have been devised to give the refuse
collection operation manager tools for the study of the internal workings
of his operation and insight into possible changes and their effects
upon his system.
Figures 74 and 75 are two nomographs developed to solve the
formula of the mathematical model previously presented. Using the
nomographs, various values of the parameters which affect the refuse
collection operation can be determined. The following examples use the
nomograph in Figure 74. It will be noted on the nomograph chart that:
(Q) = Mean quantity of refuse per service stop (Ib).
(d) = Mean density of refuse in the refuse collection
vehicle (Ib/cu yd).
(t) = Mean time for the crew to collect the stop and
drive to the next collection stop (min).
(T) «» Total tons of refuse collected by the crew
during the day.
131
-------
2b
r\r\
20
1C
O
^t
Z
o
1 —
Qi
LU
Q_
I—
GO
01 n
u
K.
0
ul
-
-
-
-
-
-
-
- ^
-
-
-
-
-
-
-
-
-
-
-
-
-
-
I I I 1
0 1
-m""*""""*""*"^
1 1 1 1
5 :
.«•••
••"• cs
1 1 1 1
>0 2,
= 2
_ i i i i
5 3
111!
0 3
K = 100
B = 10
Q - 50
CS = Cre\A
** * * * *"*«ae»^
1 1 1 1
5 4
-
-
f Size ~
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
i i
0
VOLUME OF TRUCK (CU YD)
132
FIGURE 67
COST PER TON
BACKYARD SET-OUT WITH
CURBSIDE COLLECTION
-------
25
20
K =75
B =25
Q = 50
CS = Crew Size
15
Z
o
a:
LLI
o.
co
O
u
CS-2, t
= 1.332
10
0 I i 1
i i
10
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
133
FIGURE 68
TOTAL COST CURVES
CREW COMPARISON
-------
K =90
B =40
Q = 80
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
134
FIGURE 69
TOTAL COST CURVES
CREW COMPARISON
-------
K = 90
B =40
Q = 80
lOOt
10
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
FIGURE 7.0
AVERAGE SERVICES COLLECTED PER CREW
CREW COMPARISON
135
-------
800
700
S 600
ID
Q
LU
t—
LU 500
o
u
CO
LU
400
300
200
1.0
J I I I I I I I I I I I I
CS = 3,
CS = 2,
CS = 1,
15
K =75
B = 25
CS = Crew Size .
t = 0.761
t = 1 .332
t = 1.911
20 25 30 35
VOLUME OF TRUCK (CD YD)
40
136
FIGURE 71
AVERAGE SERVICES COLLECTED PER CREW
CREW COMPARISON
-------
0.70
0.60 -
0.50
LU
U
>
LLJ
Q.
I—
CO
o
u
0.30
0.20
0.10
10
15
20 25 30 35
VOLUME OF TRUCK (CU YD)
FIGURE 72
COST PER SERVICE
CREW COMPARISON
137
-------
0.70
K = 90
B =40
= 70
CS = Crew Size
0.10L-LJ
20 25 30 35
VOLUME OF TRUCK (CU YD)
40
FIGURE 73
COST PER SERVICE
CREW COMPARISON
138
-------
u>
FIGURE 74
NOMOGRAPH NO. 1
SYSTEM DESIGN
-------
REFERENCE
1 234
TOTAL TIME
FOR
1 234
LOADS
REFERENCE 5
r ,.300
-280
-------
(E) = Total time to collect the refuse (min). (E)
does not include haul, disposal, or other non-
productive times, but is simply the time on the
collection route.
(SC) = Number of services completed (number/day).
(V) = Vehicle volumetric capacity (cu yd).
Example 1
Knowing the total quantity of refuse collected by a crew or
crews and the total number of service stops served, the mean or average
quantity of refuse per service stop can be calculated as follows:
Plot the total number of services on the scale marked (SC);
plot the total weight of refuse on the scale marked (T). Connect these
two points by a straight line (see Line 1 on Figure 74) and extend the
line to the scale marked (Q). The point found on (Q) is the average
quantity of refuse per service stop. The same procedure may be used
to estimate the total weight of refuse given the number of services
collected and the average quantity of refuse per service stop, as follows:
Plot the average quantity of refuse per service on the scale
marked (Q) and the total number of services collected on (SC). The
straight line (Line 1) connecting these two points will indicate the
total quantity of refuse collected in tons where the line crosses the
scale marked (T).
Example 2
To calculate the average density of the refuse in the truck,
the following procedure can be used:
On the scale marked (T), plot the weight in tons of a full
load of refuse. On the scale marked (V) , plot the volumetric capacity
of the truck. A line connecting these two points, shown as Example
Line 2, extended to the scale marked (d), will indicate the average
density in Ib per cu yd of the refuse in the truck. As in Example 1,
knowing any two of the values of (d), (T), and (V), the other value can
be found by proper procedures.
Example 3
If any three of the following is known, (0), (V), (d), and
(SC), the fourth value can be calculated. For example, assume that (Q),
(SC), and (V) are known. To find (d), the procedure is as follows:
Plot (Q) and (SC) on the appropriate scales and join with a
straight line (see Line 1). Where this line intersects the scale for (T),
connect that point with the value for (V), and extend to the value of
(d) on scale (d) (see Line 2).
141
-------
Example 4
To calculate the total collection time per load (E), the
procedure would be as follows:
Knowing (V), (d), (Q), and (t), first plot the value for (V)
and (d) and join these two points with a straight line (see Line 2).
Where this line crosses the scale of (T), join that point with the value
of (Q) and extend this line to the scale of (SC) (see Line 1). Join the
point of intersection with (SC) with the proper (t) value on the (t)
scale. The point where this line (Line 3) intersects the (E) line gives
the total collection time for the load. The knowledge of actual values,
or the use of assumed values, for any five of the scales on the nomograph
can enable the user to determine the other two values. In addition,
if (T), (E), (SC), and (V), are known, we can determine (Q), (d), and
(t). The procedure would be as follows:
(Q) can be determined by extending a straight line through
(T) and (SC) (Line 1) ; (d) can be found be extending a straight line.
through (T) and (V) (Line 2); and (t) can be found by extending a
straight line through (SC) and (E) (Line 3).
The second series of examples given will deal with Nomograph
2 shown on Figure 75. This nomograph has been devised to aid in deter-
mining the total time required for the collection and disposal of 1, 2,
3, or 4 loads. In order to use the nomograph, four values must be known.
These are (K), the total non-productive time as defined earlier in the
report; (B), the one-way travel time from the route to the disposal site;
(E), which is the on-route collection time for one full load; and (D),
which is the dumping time per load. The procedure would be as follows:
Plot each of the values of (K), (B), (E). and (D) on their
respective scales on the nomograph. Assume for this example that they
are 150, 10, 180, and 10, respectively. Join the point (K) and the
point (B) with a straight line (Line 1). This line intersects the
Reference lines numbered 1, 2, 3, and 4 at four different points. Now,
join the plotted points of (E) and (D) with a straight line (Line 2).
Where this line intersects Reference Line 5, mark a point (Point 5).
Join Point 5 with the respective points where the line drawn between (K)
and (B) intersects Reference scales 1, 2, 3, and 4. Construct four
separate lines (see Lines 3, 4, 5, and 6). Now, each of these four
lines crosses the Total Time scales 1, 2, 3, and 4, at the total time
required by the crew to collect, haul, and dispose of 1, 2, 3, or 4
full loads respectively. Note that in this example the crew could
collect and dispose of one full load in 345 minutes but would require
560 minutes to collect and dispose of two full loads. One full load
and partial second load would probably be planned, therefore.
142
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The value of collection time (E) available for any number of
loads can be determined by reversing the above process. For example:
assume that the total collection time available for each of three loads
is to be determined. On the Total Time scale, mark the scale designated
3 with a point at 480 minutes (Point 3), which is assumed to be the
desired total day time for the crew. Assuming the same values for (K)
and (B) as in the previous example, join a straight line from the 480
point on Total Time scale 3 to the point where the K-B line crosses
Reference scale 3 (Line 7). Extend Line 7 to the right, to intersect
Reference scale 5 between (E) and (D). Draw a straight line (Line 8)
from (D) through this point on Reference scale 5 to intersect (E) at the
available collection time in minutes for each of the three loads, 83
minutes in this example.
Nomograph 1 can also be used for a preliminary evaluation
of the crew size and the truck volume to be used for a given route size.
The procedure would require a preliminary study during representative
periods of the year of the actual collection of refuse using various
crew sizes. If collection time per stop values presented within this
report are used, alternative crew sizes would not be required. The
following items would be recorded during this field study:
(a) Haul time in minutes to the disposal site (B).
(b) Non-productive time (K).
(c) Full load weights of refuse.
(d) Disposal time per load.
(e) Number of services collected each load (SC).
(f) On-route collection time per full load (E).
It is not necessary to use a particular truck size for this
preliminary study.
The desired length of day can be assumed as any value;
however, we shall use 480 minutes, equal to 8 hours. From the field
data for the number of services collected (SC) in time(E), the average
time per collection stop (t) can be determined using the nomograph on
Figure 74. The average quantity of refuse per stop (Q), can be de-
termined from the same nomograph using field values of (T), the total
weight collected in full loads, and (SC), the number of services
collected. Similarly, the average density of refuse in the truck can
be determined from the plotted values of (T) and (V). Knowing (t), (Q),
and (d), the loading time (E) and services collected (SC) per full load
can be estimated for various truck volumes and crew sizes. It is
convenient to construct a table for the purpose of recording various
values, and an example is shown as Table XXV.
143
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TABLE XXV
EXAMPLE TABLE - NOMOGRAPHS
(V)
Volume
of Truck
12
16
20
(CS)
Crew Size
1
2
3
1
2
3
1
2
3
(t)
Time
Per Stop
(E)
Time
Per Load
(S)
Services
Per Load
Truck
Loads
Required
144
-------
Column 6 on Table XXV, truck loads required, is calculated
by dividing the total number of services on the route by the services
per load, Column 5. The time per stop for the respective crew size can
be based upon either the values (Shown on the figures included in this
report or the values determined during the preliminary study. Column 4,
the time per load, can be estimated from the use of the nomograph on
Figure 74, based upon (t) and (SC). Column 5, the services per load,
will be based upon the field data on the tonnage per load and the
average quantity of refuse per service stop.
E. Equipment
1. General
The scope of work of the contract required the compilation
of background information, specifications, and brochures on refuse
collection equipment suitable for use by the one-man crew. Such a
compilation has been completed and is included as Attachment C to this
Final Report. Brochures have been obtained from American and European
equipment manufacturers.
Although certain equipment is more efficient for one-man
collection than others, many types of available refuse collection equip-
ment may be operated by one man. We have therefore compiled a reasonably
complete listing of existing refuse collection equipment suitable for
one or more man operations.
Appendix G is a summary of pertinent specifications from
manufacturers of American equipment. It provides the manufacturer's
name and address and a brief description of the types and sizes of
equipment available. Detailed specifications are available from the
manufacturer.
2. Equipment Characteristics
Of existing American-made refuse collection equipment, the
side-loading, packer type vehicle is probably best suited for one-man
collection operations regardless of methodology. As brought out in
Section C, this equipment enables the operator to complete the collec-
tion task with a minimum of lost-time effort. With curbside collections,
the side-loading packer equipped with right-hand drive may prove more
efficient. The costs involved in installing the right-hand drive equip-
ment on the truck must be known in order to complete a cost-benefit
study. Figure 31 indicates the potential savings in collection time per
service stop possible with the use of a right-hand drive equipped
vehicle in comparison with the conventional vehicle. Assuming a useful
truck life of 5 to 8 years, if the crew completes 200 to 400 collection
stops each day, even minor time savings can become significant over the
life of the vehicle.
145
-------
Rear-loading packers are satisfactory for one-man operation,
although somewhat less efficient than side-loaders in terms of crew time.
There is some disagreement within the industry on whether the rear-
loading packer is more efficient for processing and compressing the
refuse than the side-loading packer. During the field surveys, the
side-loading packer was more susceptible to the wind blowing light
refuse materials out of the hopper; in addition, the packing mechanism
tended to become less efficient as the full load capacity of the truck
was approached. However, the particular side-loading model studied
was designed to permit continuous loading into the hopper. In most
rear-loading packers, a cycle time is involved, and lost time results
when loaders are required to wait for the packing mechanism to complete
its cycle prior to loading additional refuse.
For one-man curbside collection of refuse, the ideal collec-
tion vehicle would locate the driver and the packing mechanism close
together; it would also locate the driver close to the containers at
the service stop. Ideally, the man should step directly from the cab
to the container location, then pivot and load the containers directly
into a hopper immediately adjacent to this position. The cover of this
report illustrates such an idealized condition. The capacity of the
hopper should be adequate so that quantities involved in one stop would
not require the driver to operate the packer mechanism. Safety, of
course, is of the utmost importance, and adequate safeguards should be
standard equipment on any truck. Included should be a positive braking
system; guards to prevent the operator from becoming entangled in the
packing mechanism; and conveniently located controls on the packer
mechanism such that in case of accidentally catching an arm or hand in
the packer mechanism, the man can positively stop the mechanism at any
point. Adequate mirrors should be installed on the truck to provide the
driver with maximum visibility while driving. The wheel base on the
truck should be as short as possible consistent with the necessary wheel
base dimensions and axle capacities for efficient vehicle design. The
figures in the mathematical analysis section of this report indicate that
the larger sized vehicles will generally enable more efficient refuse
collection regardless of crew size. There is, of course, a practical
upper limit to this, depending upon the time required to drive between
collection stops, other non-productive time, disposal time, and route
factors such as street widths, alley widths, and the presence of
obstructions to the passage of the vehicles. Ideally, the crew would
travel to the route, collect one full load of refuse, and complete its
trip to the disposal site and back to the yard, all within eight hours.
Thus, the crew would spend the maximum amount of time on the route,
collecting refuse.
146
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3. European Equipment
A great deal of foreign equipment has been produced.
However, to our knowledge none of this equipment is extensively
purchased in the United States. Many systems in Europe use more
sophisticated equipment than that used in the United States. Light
alloy steels are used for truck bodies, and the systems for mechani-
cally handling containers often maintain dustless conditions.
Elaborate screw-conveyor compactors are also common. Although their
maintenance costs may be higher, the screw-conveyor type vehicles
have an advantage in that the partially disintegrated refuse is some-
times easier to dispose of at the incinerator or landfill site. In
general, European systems use larger sized crews.
Photographs XII through XV illustrate typical European
collection equipment.
147
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PHOTOGRAPH XII.
DUSTLESS COLLECTION
SYSTEM,
VIENNA, AUSTRIA
NOTE: AUTOMATIC
LIFTING DEVICE.
I !! ?!
PWT
PHOTOGRAPH XIII.
SCREW COMPACTOR
ATHENS, GREECE
148
-------
PHOTOGRAPH XIV.
SCREW COMPACTOR
CENTRAL EUROPE
NOTE: SHOULDER
HEIGHT LOADING
PHOTOGRAPH
COMPACTION
VEHICLE
NEVI, FRANCE
149
-------
GLOSSARY
Adjusted Standard Time
Alley Collection
Backyard Collection
Box
Bundle
Can
Collection Methodology
Collection Stop
Collection Time
Container
Cost per Service
Cost per Ton
Standard Time plus allowance for fatigue,
personal and unavoidable delays.
The collection of refuse placed adjacent to
the alley by a crew collecting from both sides
of the alley with each pass of the equipment.
The collection of refuse located at the rear
of the service by a crew operating from the
street fronting the property and collecting
from both sides of the street with one pass
of the equipment.
Cardboard, paper, wood or other container for
refuse normally intended for disposal along
with its contents.
Prepared garden trimmings, tied paper, or
other similar material placed for collection.
Conventional metallic, fiberboard or other
reuseable refuse container fitted with handle
and a lid.
Method and procedure followed by the refuse
collection crew in completing their work
assignments.
Stop made by the collection vehicle and crew
on the route to collect refuse from one or
more service stops.
Elapsed or cumulative time spent by the refuse
collection crew in collecting refuse from a
collection stop. Does not include travel time
between collection stops on the route.
Can, box, or disposable container used for
storage of refuse.
Average cost per service stop including labor
and equipment costs.
Average cost per ton of refuse collected
including labor and equipment costs.
150
-------
Crew Size
Curbside Collection
Disposable Container
Frequency
Haul Time
Least Squares Line
Level of Service
Load Mean Quantity
Load Standard Deviation
Man-Minutes per Ton
Mean Quantity of Refuse
Median
Number of persons assigned to each refuse
collection vehicle, including the driver.
The collection of refuse placed at the curb
location by a crew wherein collection is
made at each service stop on one side of
the street with each pass of the equipment.
Plastic, paper, cardboard, or other container
for refuse intended for disposal along with
its contents.
The number of times a given event occurs;
expressed as a percentage of all recorded
occurrences.
Elapsed or cumulative time spent hauling
collected refuse from the route to the
disposal point and return to the route.
A straight line representing a set of data
such that the difference between the value
on the straight line and the corresponding
data points is minimized.
Extent of refuse collection service provided
to the recipient, including collection
frequency; material collected; storage
location; pre-preparation; and other factors.
The total weight of one load from many service
stops divided by the total number of those
service stops.
Square root of the mean of the squares of the
deviations of, the Load Mean Quantity from the
Mean Quantity of Refuse.
Total labor minutes expended per ton of refuse
collected. Route man-minutes per ton refers
to only the portion of total labor time
expended while the crew is on the route.
The cumulative total weight of all loads
divided by the cumulative number of all
service stops.
Statistical point in a series at which the
number of items with higher values is equal to
the number of items with lower values.
151
-------
Modified Curbside The collection of refuse placed at the curb
Collection location by a crew wherein each collection
stop is made for two or more services and
both sides of the street are collected with
each pass of the equipment.
Service Stop Residence, commercial establishment, or
other living or business unit receiving
periodic refuse collection service.
Standard Time MTM time required for the completion of a
work task. Does not include allowance for
fatigue, personal, and unavoidable delays.
Total Items Total number of containers and bundles at
the service stop.
Travel Time The elapsed or cumulative time of travel
between collection stops on the route.
Truck Capacity Volumetric capacity for refuse.
152
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158
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DATE
APPENDIX A
UNITEIX STATES. PUBLIC HEALTH SERVICE
RALPH STONE & CO., INC., ENGINEERS
REFUSE COLLECTION DATA SHEET
CLIMATE
COLLECTION AGENCY_
CREW SIZE
EQUIPMENT DESCRIPTION
BODY MANUFACTURER
CAPACITY_
TYPE
HOPPER SIZE_
CHASSIS
DRIVER LOCATION,
AXLES
MAX. LEGAL LOAD
COMMENTS
(CUBIC YARDS)
(CUBIC YARDS)
(RT. OR LEFT)
.(TONS)
ROUTE INFORMATION
Leave yard
Arrive route
DATA
WRISTWATCH
TIME
ODOMETER
MILEAGE
NET
TONS
Leave Route (1st load)
Arrive @ Disposal Site
Leave Disposal Site
Arrive Route (2nd load)
Leave Route
Arrive @ Disposal Site
Leave Disposal Site
Arrive @ yard
159
Page 1 of
-------
APPENDIX A - CONTINUED
CANS BOXES BUNDLES #UNITS COLLECTION TRAVEL LOST TIME REASON FOR L05T TIMS
160
PAGE OF
-------
APPENDIX B
UN'TED STATES PUBLIC
HEALTH SERVICE
RALPH STONE AND COMPAN<, INC.
ENGINEERS
CONTRACT PH 86-67-248
DATA SUMMARY FORM
REFUSE COLLECTION OPERATIONS
Agency_
Date
Crew Size
Equipment Description:
Body Manufacturer:
Capacity
Type
Hopper Size_
Chassis
Driver Location^
Axles
Climate
Max. Legal Load_
Cubic Yards
Cubic Yards
(Rt. or Lt.)
Tons
I. TOTAL TIMES AND MILEAGE (Exclude Lunch and Break Time)
Item
Yard to Route
On Route (First Load)
Route to Disposal Site
Disposal Site to Route
On Route (Second Load)
Route to Disposal Site
Time
Miles
161
-------
APPENDIX B - CONTINUED
I ten
Disposal Site to Route
On Route (Third Load)
Route to Disposal Site
Disposal Site to Yard
Total For Day
Route to Yard
(Return with Partial Load Only)
Lost Time and Mileage
Lunch:
Tirr.e
Miles
Minutes.
BREAK,
Total Disposal
II. INCREMENTAL TIMES
Minutes
Time/Stop
Time Increment (Minutes)
0 - 0.20
0.21 -*0.40
0.41 - 0.60
0.61 - 0.80
0.81 - 1.00
1.01 - 1.20
1.21 - 1.40
1.41 - 1.60
1.61 - 1.80
1.81 - 2.00-
Over 2.00
Minimum Value:_
Maximum Value:
Number Occurrences
.(Minutes)
.(Minutes)
162
-------
APPENDIX B - CONTINUED
Tirr.e Increment Minutes
Travel Time.Between Stops
Number Occurrences
III. DISPOSAL SUMMARY
First Load
Second Load
Third Load
Fourth Load
Partial Load
(Minutes)
(Minutes)
Net Tonnage
Total # Stops
IV. CONTAINER SUMMARY
Average Number of Cans/Stop:_
Average Number of Boxes/Stop:
Average Number of Bundles/Stop:
RPS/8-67
163
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APPENDIX C
POSSIBLE COLLECTION COST SAVINGS ATTRIBUTED TO THE
USE OF DISPOSABLE CONTAINERS
The following estimate has been prepared based on information
received from Municipality 'A' obtained during the conduct of
comprehensive time studies of field collection operations.
I. Present average cost per ton for collection and disposal of
solid wastes from residences:
Yearly Average: $9.00/T
Less Disposal Cost: 1.25
Collection and Haul Cost: $7.75/T
Assume 10% for City and Administrative Overhead:
(9.00) = $0.90/T
New Collection and Haul Cost (Crews & Equipment Only)
II. Based on preliminary survey studies, a potential reduction in the
incremental time for a collection stop consisting of three items
will be about 40 percent assuming the replacement of conventional
containers with disposable containers. Studies indicated that
on the average three cans were used by householders each week.
This potential saving applies only to the portion of the collec-
tion day when the crew is actually collecting refuse, and not
when traveling between collec;,ion stops, to and from the disposal
site, etc.
A conservative estimate based on Field Studies indicates that the
typical crew in Municipality 'A' collects from an average of
260 collection stops.
The average time of travel between stops is presently 0.17
minutes.
Therefore, if each collection stop required 40 percent less time
to collect, the additional time available for collection of refuse
could be expressed as follows:
164
-------
APPENDIX C - CONTINUED
260(0.60)3+ 260 (0.17) +x (0.68) + X(0.17) = 260(3) + 260(0.17)
Simplifying:
1403
X =
0.63 + 0.17
Where 3 = Average collection time per stop (conventional
containers) .
X = Number of additional services per day.
Based on values for collection time as determined during the
One-Man Collection Study:
3 = 0.63
Therefore,
X = 120
Each collection vehicle could be expected to collect about 120
additional stops; thus, for every four trucks presently used,
one could be eliminated. This indicates an approximate saving
of 25 percent in collection costs. The capacity of collection
vehicles may have to be increased to accommodate the additional
refusej however, this factor has been omitted in this analysis.
Net savings per ton would be 25 percent ($6.85) or $1.71/T. If
it is assumed that the average household produces 1-1/2 T of refuse
per year, a savings per household of about $2.57/Year is indicated,
or approximately $0.05 per household per week.
This conservative estimate of the possible savings in collection
cost resulting from the use of disposable containers would pay
about 15 to 20 ccent of the estimated weekly cost of disposable
bags.
In addition, the cost of purchasing and periodically replacing
conventional containers would be eliminated.
The cost of conventional containers can be estimated as follows:
Assume 3 containers with an average 3-year life costing $5.00 each.
Cost/Week = ^l^ = 9-6(?/Week
Total Savings Possible: 5.0$ (Collection)
9.6c (Containers)
Total: 14.6c/Week
165
-------
APPENDIX C - CONTINUED
This total could represent nearly 50 percent of the weekly cost
of both the disposable bags and holder. Potential collection
savings may be considerably greater in multi-man crews due to
the greater unit costs for collection per ton.
166
-------
APPENDIX D
JNATIONAL SURVEY DATA FORM
RALPH STONE AND COMPANY, INC.
ENGINEERS.
REFUSE COLLECTION INFORMATION
I. NAME OF CITY:
II. COLLECTION INFORMATION (Residential or Residential/Commercial only; Please do
not include street sweeping, snow removal, tree trimmings, etc.)
A. Materials Collected: Combined Refuse Combustible only Wet
Garbage only Yard Refuse only Non-Combustible only
Comment:
B. Collection Frequency: I/week 2/week Comment:
C. Number of Residential Units Served:
D. Number of Commercial Units Served:
E. Refuse Tonnage(Items in IIA above only) Collected/Year:
F. Average Number of Lost Time Accidents(Industrial Only) per Year:
III. REFUSE COLLECTION EQUIPMENT
Please list the equipment used for the collection of waste materials
named in IIA above by type and cubic yard capacity and. number of each
normally utilized.(Type-rear loading packer, side loading packer, front
bucket loader, open truck, other(please specify).
IV. GENERAL
Total Annual Budget for Refuse Collection(please include equipment
maintenance, but exclude disposal costs such as dump fees, incinerator
operations, etc.)
V. COMMENTS
VI SPECIAL NOTE
Please provide a copy of the current refuse collection ordinance or
regulations for your City.
PREPARED BY:
Name:
Title: Date:
167
-------
APPENDIX D - CONTINUED
I. Name of City Population_
Residential Collection Provided By: Municipal Private
II. Collection Information (Residential or Residential/Commercial
Service Only)
A. Normal Crew Size (One-Man) (Two-Man)
Other (Please Specify)
Comment
B. Normal Collection Location: Curb or Alley
Other (Please Specify)
C ommen t
C. Collection Information: Municipal Private
1. Number of collection services
2. Number of commercial services
3. Average Number of Crews/Day
4. Average Tons/Day/Crew
5. Average Working Day (Hours)
6. Tonnage Collected/Year
7. Annual Budget for Collection j> _$_
D. Equipment Utilized - Please indicate the type, model, and cu yd
of collection utilized by the various crew sizes (rear loading
packer, side loading packer, front bucket loader, open truck,
other (please specify).
III. General
A. Total Tonnage Collected/Year Tons
B. Annual Budget for Collection $
IV. Comments
NOTE: Please provide copy of 1967-68 solid waste ordinance and Annual Report,
Prepared By:
NAME
TITLE 168 DATE
-------
APPENDIX E
RALPH STONE AND COMPANY, INC., ENGINEERS
U.S.P.H.S. PH 86-67-248
SUBJECT
RECORDER_
DATE
200
150
CO
1
o
0)
100
LOADING HEIGHT_
CAN WEIGHT
TIME
TEMPERATURE_
HUMIDITY
CANS IN GROUP
50
10 12 14 16 18 20
CAN GROUP NUMBER
22
24
26
28
30
32
34 36
4/68
-------
APPENDIX F
VIDEO TV USE FOR HUMAN, FACTORS STUDIES
Advantages of the unit include the following:
(1) Allows a continuous record which can be consulted to
verify data for any portion of the experiment. If the information
is not needed, the tape can be reused for a subsequent experiment.
This is the main advantage of video tape recording equipment over
a movie camera.
(2) Use of the unit allows spot checking of observer
recorded data by reobserving and recording sample data from the
video tape.
(3) In human factors experiments involving physical labor,
the possible legal liability involved in the experiment may be
lessened by having a permanent record of work activity conducted
during the experiment.
(4) A new variable previously not thought important may
become important during the experiment, and this factor may be
evaluated based upon the video tape record.
(5) Allows management or clients to view the conduct of
the experiment at a time more convenient to individual schedules.
(6) It allows retrieval of experimental data which might
otherwise be lost due to misplacement, observer error, or other
problems.
(7) It allows the possibility for subjective evaluations
of the subject's physical or even mental state at some point in the
experiment.
(8) Depending on the experimental design, the use of the
TV video system along with special timing or electronic apparatus can
be made to periodically or randomly sample the experimental data
without the presence of a continuous observer for data recording.
(9) The presence of a continuously monitoring system can
prevent data falsification by a. subject.
(10) The amount of data desired may be excessive for one
or two observers to record during the conduct of the experiment. The
video tape system can preserve all the information and allow detailed
data recording at a more convenient time.
170
-------
APPENDIX F - CONTINUED
There are, of course, certain disadvantages which may preclude
the use of the TV video system in certain experimental designs. Some
of these could be the following:
(1) The presence of a monitoring device that continuously
records personnel characteristics may tend to inhibit the performance
of the subject.
(2) The recording device should be present during all
experimental trials; otherwise, the subject's performance may vary
as a function of its presence.
(3) For the TV video system to be useful to its fullest
extent, a qualified technician or other observer must spend time
reviewing the video tape recordings.
(4) The cost of the unit.
(5) The experiment must be conducted in a location where
power is available to operate the video TV system. A portable unit
may be used in short-term experiments where power is not available.
The battery life on typical systems is on the order of 20 minutes.
171
-------
APPENDIX G
EQUIPMENT SPECIFICATIONS
MANUFACTURER
Name and Address
Bvnal Products, Inc.
11990 Franklin Ave.
Franklin Park, Illinois
60131
Cohey Perfection -
Cobev Company
Division of Harsco Corp.
Calion, Ohio
Cushman Motors
Division, Outboard
Marine Corn.
Lincoln. Nebraska
Dempster Bros., Inc.
Knoxville 17, Tenn.
E-Z Pack Co.
Division of Hercules
Galion Products, Inc.
Calion, Ohio
Garvood Industries, Inc .
Wayne, Michigan
Model Description
6 Yd. Kussler
8 Yd. Hussler
Cobey Paktainer PT 1224
PT 1230
Cobey Traln-Tainer )
Containers)
Cushnan Refuse
Collection Vehicle
Demnster Uumpmaster
Container Train
Loader UP-3B-20-DB
FL 45-20
FL 45-25
FL 45-30
Econo Train
Container CT-4
Unit CT-5
SL 16
SL 20
SL 24
A 16
A 20
A 24
LP 716
LP 718
LP 720
LP 725
T-130 L*
OUTSIDE
DIMENSIONS
Height
(in.)
76
76
1.3.
74
Width
(in.)
82
82
Length
(in.)
114
BODY
Weight
2000
138 2300
I.D. ;i.D.
84 204
74 i 84 ]246
53-5/4 59-3'S 93
5i • 59-3/d 93
: I
70
45-1/:
i
I
103-1/3 96
1
103-1/3 96
J
103-1/2 96
|
1 i.u.
50 ' 72
56-1/2
81
81
81
81
81
31
94
94
94
94
120
72
95-1/2
95-1/2
95-1/2
95-1/2
95-1/2
95-1/2
95-1/2
95-1/2
95-1/2
95-1/2
129
1282
293 «
>-
323
"u
c
39'. «
108
112
181
205
239
181
205
239
232
250
265
299
330
13750
14560
15620
1100
1200
7108
7808
8758
7108
7R08
8758
8800
9080
9300
9780
22900
Volume
(cu yd)
5.9
7.3
24
30
it
1-1/4
20
25
30
4
5
16-3/4
20
24
16-3/4
20
24
16
18
20
25
40
LOADING
LOCATION
Front
•
.
Top
Top
Ton
.
•
•
•
.
•
Side
& Ton
& Top
(•)
(•)
9
(•)
(«)
(*)
ma Top
• 6 Top
• & Top
• 4 Top
•& Top
ft, Top
Rear
,
,
,
•
•
DIMENSIONS
Height
(la.)
5"
57
(30)
84
84
(30)
13-3/4
13-3/4
13-3/4
38
Width
(in.)
(34)
96
96
(30)
L.88
80
L.88
80
L.88
80
36
36
48
36
36
48
80
IXMDDU
HEIGHT
(in.)
7^ ovei
Frame
1\ ovei
Frame
53-5/8
46-5/8
36
50
56-1/
V
O '—*
c i*
r-i
C
35
PACKING SYSTEM
Aux .
Eng.
Oper .
Press .
(78000)
(78000)
i
i
68000)
1150
1150
1150
(76600)
(76600)
(76600)
(76600)
(76600)
(76600)
1050
1050
1050
1050
Dead
Time
10
10
10
10
20
EQUIPMENT
TYPE
Open
Body
Com-
pactor
V
,
V
•
•
•
.
•
m
•
.
,
•
*
•
•
•
•
•
.
•
•
•
•
Containers Available
(Self-contained unit-dimensions
include cab and wheels)
ftT-100 SeriDs has 11 models, front and rear loaders, u/varying specs.
( ) = lb pressui
when PSI not avail.
-------
APPENDIX G (Continued)
EQUIPMENT SPECIFICATIONS
MANUFACTURER
Name and Address
The Heil Company
Milwaukee, Wise. 53201
Hobbs Trailers
609 N. Main Street
Fort Worth, Texas
Leach Company
222 West Adams St.
Chicago, 111. 60606
Lodal, Inc.
P.O. Box 791
Kingsford, Mich. 49802
Model Description
Colectomatic Mark III
Hobbs Hyd-Pak Rear
Loader - HRL 18
HRL 20
HRL 25
Hyd-Pak 60 Series -
2 ^ 6013
' ?! -3 6016
c c RJ
3 o j? 6020
<-" 6024
Hyd-Pak Trailer Units
(as transfer units)
"
Hyd-Pak M Series - M18
M21
M25
Hyd-Pak Packing
Containers
Leach 2R Packmaster
Leach Pakmaster
EVO (Detachable Body)
Load-A-Matic
Train Transfer System
Transfer Truck
Lodal Trains
OUTSIDE
DIMENSIONS
Height
(in)
83
83
83
90
89-3/4
89-3/4
89-3/4
72
84
84
84
108
131
Width
(in)
95-3/4
95-3/4
95-3/4
95-3/4
95-1/2
95-1/2
95-1/2
96
96
96
96
96
(137-1/4) 96
132-1/2]
(138-7/8) 96
150-1/2]
(156-7/8) 96
83-5/8
83-5/8
83-5/8
96
96
95
95
95
96
96
^ength
(in)
172-1/4
189-1/4
219-1/4
241-1/4
208-3/4
221-3/4
254-3/4
174
174
198
234
379-1/2
375-1/2
444-5/8
444-5/8
165
189
219
249
270
BODY
Weight
8800
9200
9700
10500
9000
9500
10000
6000
6900
7300
8300
7085
7750
8635
12600
12900
11000
Volume
'cu yd)
13
16
20
25
18
20
25
16
19
23
27
32
42
50
60
18
21
25
20-35
20
25
31
13, 16
17, 20
21,25,
30
20628
4 & 5
LOADING
LOCATION
Front
a. ^
o ft)
W
o) in c
oo n nj
p M
to H
Side
0 +
in *J
a E o.
•a o o
•HUH
CO fc
,
(Stop)
*
(&top)
,
(Stop)
,
.
.
»
(4 Top
•
•
Rear
.
•
•
•
•
,
•
9
,
,
.
DIMENSIONS
Height
(in)
54
54
54
54
72
72
72
(L 96)
(L 96)
(L 96)
56
56
56
48
Width
(in)
80
80
80
80
79-1/2
79-1/2
79-1/2
(96-)
(96-)
(96-)
80
80
80
77
LOADING
HEIGHT
(in)
i m
oj ex a
JO O to
•H S *"
U1 rH O
>
-------
APPENDIX (Continued)
EQUIPMENT SPECIFICATIONS
MANUFACTURER
Name and Address
Marlon Metal Products
Co. , Marion, Ohio
M - B Company
New Holstein, Wise.
Pack-Mor Mfg. Co.
1123 S.E. Military Dr.
P.O. Box 14147
San Antonio, Texas
78214
Seal Press - Division
of Tampo Mfg. Co., Inc.
1146 W. Lowell- St.
P.O. Box 7248
San Antonio, Texas
78207
H. E. Smith, Inc.
1069 S. Jackson St.
Defiance, Ohio
* (204) - LENGTH FROM Bt
Model Description
20 S
Hydropaka Model Q
Trash Tainer Body
M - B Pack King
RLA 1315
RLA 1615
RLA 1815
RLA 2015
RLA 2515
RLA 3015
3 RL
Hydraulic Packer
^Cylindrical Body)
Stationary Packer &
Side Loader Avail.
Transfer Trailers
Lo-Boye Trailer (cylind
Front Loader
Mark '16' a "a >,
Mark '20' r-i -H o
Mark '24' o •o
Smlthpac 5
Smithpack 10
MPER TO TAIL.
OUTSIDE
DIMENSIONS
Height
(in)
74-1/2
60
35-1/2
44
90
90
90
90
88
88
88
88
88
88
87
87
87
87
95
91
91
91
84-1/2
84-1/2
Width
(in)
96
90
26
39
T3 ^
•H 4J CO
0) TJ CO
C -H
H 3
96
96
96
96
96
96
87
87
87
87
95
(Diam)
93
93
93
84
84
Length
(in)
186
192
56
56
156
170
198
226
177
196
213
227
262
297
165
181
210
248
248
168
192
227
120
(204)*
120
(204)
BODY
Weight
(lb)
8280
13500
320
480
9490
9840
10215
10590
10940
11290
7966
8051
8600
9400
9820
8400
8900
9500
Volume
(cu yd)
20
28
1
2
14
16
20
24
13
16
18
20
25
30
20, 25,
30
13
16
20
24
28
13 to
28
45 - 75
28 - 38
20 - 32
16-1/2
20-1/2
24-1/2
5.08
10.33
LOADING
LOCATION
Front
(also
top)
top
top
Side
0
•
•
•
•
•
(& top)
•
•
•
•
•
Rear
DIMENSIONS
Height
(in)
54
44
51-1/2
51-1/2
51-1/2
51-1/2
48
48
48
48
48
48
39
38
Width
(in)
36
34
36
36
36
36
76
76
76
76
76
76
•o
-------
APPENDIX G (Continued)
EQUIPMENT SPECIFICATIONS
MANUFACTURER
Name and Address
Sterling Mfg. Co.
241 N. Third St.
Laurens, Iowa 50554
Vel-Jac Mfg. Co., Inc.
5650 N. Broadway
Wichita, Kansas 67219
Wayne Engineering Co.
Cedar Falls, Iowa
Toledo Industrial
Fabricating Co., Inc.
1100 Bush Street
Toledo, Ohio
Western Body &
Model Description
Hippo
Pak Rat
Mighty Pack ^
(incl. chassis) X
1 -H
1 l-i M
Oh,, pal, 01 4) 0) 1
bnu-faK v< u c
------- |