HEURIST
-------
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process learned through experience that helps orga-
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commonsense thought process learned through
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-------
HEURISTIC ROUTING
This publication (SW-113) was written
for the Federal solid waste management programs
by KENNETH A. SHUSTER and DENNIS A. SCHUR
U.S. ENVIRONMENTAL PROTECTION AGENCY
1974
-------
An environmental protection publication (SW-113) in the solid waste management series
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 - Price $1.05
Stock Number 5502-00120
-------
The collection of solid wastes generally represents from 70 to 80 per-
cent of a community's total waste management costs. To help reduce
these costs, and at the same time improve the quality of community
services, over the past several years EPA's Office of Solid Waste Man-
agement Programs has been conducting studies on solid waste storage
and collection systems. This report on heuristic routing is the first of a
series of reports documenting the studies. Others will include:
• A Five-Stage Improvement Process for Solid
Waste Collection Systems
• Management Information System for Residential Solid
Waste Collection
• Policies and Methodologies for Solid Waste Collection
• Districting and Route Balancing
Additional projects are under way or planned that ultimately will
complement this information. These include studies on: rural storage
and collection systems; inner-city storage and collection systems; finan-
cial mechanisms for both capital and operating expenses; institutional
and organizational arrangements, ranging from public collection sys-
tems to open and free private competition working within various
regulatory and utility structures.
All the studies and resultant reports have two major purposes: (1) to
provide information or guidelines on the many possible alternatives for
storage and collection systems; (2) to provide relatively simple, but
effective, solid waste management tools for evaluating the systems.
These management tools are designed to measure the effectiveness and
efficiency of the various kinds of storage and collection systems, to
identify high cost centers in the systems, and to provide predictive infor-
mation on the effect of changes in the systems.
The objectives of a storage and collection system should be to provide
service that is economical, that is environmentally sound, that is
aesthetically acceptable, and that assures a continuity in service. These
same objectives also are the underlying measures of storage and collec-
tion effectiveness used in developing the guidelines and the manage-
ment tools.
-ARSEN J. DARNAY
Deputy Assistant Administrator
for Solid Waste Management
111
-------
-------
INTRODUCTION 1
MICRO-ROUTING—WHY AND WHEN 5
HEURISTIC APPROACH 6
TO MICRO-ROUTING
PROCEDURES FOR MICRO-ROUTING 13
PATTERN METHOD OF ROUTING 16
FACTORS TO CONSIDER FOR 19
IMPLEMENTATION
APPLYING HEURISTIC ROUTING TO 23
HUNTINGTON WOODS, MICHIGAN
CONCLUSION 38
EXERCISES 38
REFERENCES 45
ABSTRACT 45
TABLES 24
24
30
30
what is the heuristic approach
to problem solving?
what is routing?
why a heuristic approach to micro-routing?
what is the value of micro-routing?
when should it be used?
what are the heuristic rules for micro-routing?
what routing patterns should be applied?
how are the heuristic rules applied?
what preparations are needed for routing?
what data are required for routing?
routing, how is it done?
evaluating existing policies
compiling the data
reviewing existing and alternative operations
determining the new routes
implementation considerations
effectiveness of the micro-routing program
table 1. seasonal variations in solid waste
collection—City of Huntington Woods, Michigan
table 2. residences serviced by day of week
and truck [Huntington Woods]
table 3. time required for various collection
activities [Huntington Woods]
table 4. old and new collection routes
[Huntington Woods]
-------
-------
what is the
heuristic approach
to problem solving?
The heuristic approach to problem solving con-
sists of applying human intelligence, experi-
ence, common sense and certain rules of thumb
Cor heuristics) to develop an acceptable, but
not necessarily an optimum, solution to a prob-
lem. Of course, determining what constitutes an
acceptable solution is part of the task of decid-
ing what approach to use; but broadly defined,
an acceptable solution is one that is both reason-
ably good (close to optimum) and derived with-
in reasonable effort, time, and cost constraints.
Often the effort (manpower, computer, and
other resources) required, the time limits on
when the solution is needed, and the cost to
compile, process, and analyze all the data re-
quired for deterministic or other complicated
procedures preclude their usefulness or favor
the faster, simpler heuristic approach.
Thus, the heuristic approach generally is used
when deterministic techniques or mathematical
models are not available, economical, or prac-
tical. Its use, according to Bowman and Fetter,
predominates in at least three circumstances:
1. Where problems are so complex that, though
the essence of the problem may be stated in
a mathematical framework, the computation
required is quite unfeasible, even on the
largest computer.
2. Where problems—especially policy prob-
lems with which top managers must grapple
—are so amorphous that a mathematical
model cannot capture their most important
characteristics.
3. Where, although a mathematical model may
be successfully employed, the prelude to the
model and the work subsequent to the model-
ing must be of a less formal nature. 1
Most complex problems encountered in the
real world fall into one or more of the preceding
categories and often can be solved through the
use of heuristics. Or, frequently the most eco-
nomical and practical approach is a combina-
tion of rigid models and heuristics.
what is routing?
The term routing has been applied to solid
waste management in several different ways.
As a result, several models or approaches to
solid waste routing have been developed, each
of which addresses itself to a very different
problem. The problems, or models, may be
divided into three categories: macro-routing,
districting and route balancing, and micro-rout-
ing (Figure 1).
Macro-roufing determines the assignment of
daily collection routes to existing processing
and disposal sites. The objective is to optimize
the use of processing and disposal facilities in
terms of the daily and long-range capacities and
operating costs of the facilities, while minimiz-
ing the round trip haul time (and hence the
hauling cost) from the collection routes to the
processing or disposal sites. Information essen-
tial to macro-routing includes haul times from
the routes to the various processing and dis-
posal sites, crew size and vehicle capacity,
expected arrival, queue, and service times at
the sites, and short- and long-range capacities
and costs of the sites. Macro-routing may also
be useful in determining which of several pro-
posed processing and disposal sites or garage
locations is most economical, again by consider-
ing such factors as costs, site capacities, and
1
-------
DISTRICTING:
DETERMINATION OF ROUTE
BOUNDARIES, ROUTE BALANCING.
Monday
Tuesday
Wednesday
Thursday
Truck #1
MACRO-ROUTING:
ASSIGNMENT OF COLLECTION
ROUTES TO PROCESSING &
DISPOSAL SITES.
ty *»;•;•:• I To landfill
To incinerator
MICRO-ROUTING:
PATH OF COLLECTION
VEHICLE ON THE ROUTE.
Figure 1. Types of routing: (1) macro-routing is assigning collection routes to
processing and disposal sites; (2) districting is determining route boundaries and
route balancing; (3) micro-routing is determining the path of collection vehicles
on the route. The heuristic approach described in this report applies to
micro-routing.
-------
round trip haul times.
Districting and route balancing determines a
fair day's work and divides the collection areas
into balanced routes so that all crews have
equal workloads. This is achieved through a
careful evaluation of how the collection crew
spends its time.
Micro-roufazg looks in detail at each daily
colleqtion service area to determine the path
that the collection vehicle should follow as it
collects from each service on its route. The ob-
jective is to minimize the driving time on the
collection route through minimizing the dead
distance (i.e., street segments that have no
services or that are traversed more than once),
backing of vehicles, U-turns, left turns, collec-
tion on major streets during rush hour traffic
and other delay times.
why a heuristic
approach to
micro-]
Traditionally there are three approaches to
problem solving: deterministic, heuristic-deter-
ministic, and heuristic.
The deterministic approach would seek to
solve the micro-routing problem by developing
a mathematical model. This model would al-
ways determine the optimum route based upon
the required input data. To date, no completely
deterministic models have been developed.
That is, there are no models that consider all the
factors pertinent to routing and that guarantee
the optimum solution through eliminating all
other possible alternatives. There are three
major reasons for this. First, it is too difficult to
quantify all the pertinent factors. Second, it
would be prohibitively costly and time-consum-
ing to investigate all the possible solutions, even
with a computer model. And third, the collec-
tion route itself is subject to so many dynamic
variables that the optimum solution may change
frequently.
As applied here the heuristic-deterministic
approach attempts to solve the micro-routing
problem by using a computer to examine many
possible alternatives and select the best alter-
native based on some heuristic algorithm. In
applying any of the computer models currently
being marketed, the user (typically a consul-
tant) must spend time becoming familiar with
the community, preparing information for com-
puter input, and adjusting and debugging the
computer program to perform the necessary
computations for each specific community. The
computer input includes information required
to develop an elaborate node system defining
the street network of the community (Figure 2)
and the characteristics of each street segment;
e.g., the length of the street and the number of
services between nodes; traffic patterns; and the
quantity of waste generated.
The heuristic approach deals with the micro-
routing problem by using a manual procedure
to develop acceptable collection routes without
examining many possible alternatives. It is
certainly possible to develop a good solution to
the micro-routing problem using either the heu-
ristic-deterministic computer models or the man-
ual heuristic approach.
The manual heuristic approach, however, has
some distinct advantages over the computer
models. It is faster, less costly, more flexible,
and easier for local personnel to apply. The
manual heuristic approach requires less data
preparation than the computer models by elim-
inating several such time-consuming tasks as
preparing information for computer input, dev-
eloping a node network, and modifying the
computer program.
The computer is a powerful and useful tool,
but in the case of micro-routing, a man can
often perform the task more economically. For
example, it is easy for a person to read a map,
but difficult to program a computer to do so.
Heuristic rules are relatively easy for an experi-
enced person to apply while considering a
variety of street and traffic peculiarities, com-
pared to the difficulty and cost of programming.
It is also relatively easy for a person to add or
modify a rule for a specific situation, or to
modify a route at a later date, compared to re-
writing programs, punching new data cards,
and rerunning a computer model. Municipal
personnel can readily understand the basis for
routings done manually—a real advantage in
implementing, in conducting daily operations,
and in making necessary modifications as con-
ditions change.
537-034 O - 74 - 2
-------
Dept.of Public Works
MILES
MILE ROAD
• DESIGNATES NODES TO BE PROGRAMMED
o
o
o
I
ffi
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what is the value of
micro-routing?
The value of micro-routing becomes obvious
when one considers the repetitive nature of the
collection process: any time saved by reducing
collection route distance and travel delays be-
comes cumulative. Assume, for example, that a
community has 10 trucks, each with a three-man
crew that services 450 residences daily in about
4 hours of on-the-route collection time. If 24 min-
utes of collection time per crew can be saved
by rerouting, then nine collection routes .can
service the same areas without taking more
than the original 4 hours by adding 50 services
to each route. The total savings represent one
collection vehicle and three man-years of labor
(one crew). To realize these savings, these 24
minutes per route must, of course, be utilized
through further rerouting and route expansion
or through a change in crew size, rather than
dismissing the collectors 24 minutes earlier
each day. The larger the collection system (i-e-
number of crews) the greater is the absolute
savings potential.
when should it
be used?
In many communities the existing collection,
routes have evolved as the communities have
grown, by sporadically adding a section here
and there to the various routes, or adding new
routes to the new areas. Rarely has the overall
route structure been periodically examined.
Thus many communities have fragmented, over-
lapping, or unbalanced routes that have un-
necessary dead distance, delay times, and in-
equitable workloads. If this is the case, micro-
routing should be used.
Rerouting is also needed whenever there is a
significant change in the collection system. Such
changes include: frequency of collection; point
of collection (curbside, alley, or backyard);
crew size; truck size or equipment type; location
of disposal sites; type of storage container [209-
liter (55-gal) drums, cans, sacks, etc.]; com-
bined versus separate waste collection; or num-
ber of services. In case of a change in disposal
sites, macro-routing should precede micro-rout-
ing to determine round trip haul time for each
route.
-------
The heuristic approach to routing is a relatively
simple and expedient method for obtaining an
efficient route layout that minimizes dead dis-
tances and delay times. The heuristic approach
could also be called the pattern method of rout-
ing since it relies heavily on the application of
specific routing patterns to certain block con-
figurations. Admittedly, efficient routing re-
quires both skill and aptitude. But guided by
certain heuristic rules and patterns, and through
experience, a router can readily develop the
ability to scan a map and rapidly and system-
atically plot timesaving routes.
what are the
heuristic rules
for micro-routing?
1. Routes should not be fragmented or over-
lapping. Each route should be compact, con-
sisting of street segments clustered in the same
geographical area.
2. Total collection plus haul times should be
reasonably constant for each route in the com-
munity (equalized workloads).
3. The collection route should be started as
close to the garage or motor pool as possible,
taking into account heavily traveled and one-
way streets. (See rules 4 and 5.)
4. Heavily traveled streets should not be col-
lected during rush hours.
5. In the case of one-way streets, it is best to
start the route near the upper end of the street,
working down it through the looping process
(Figure 3).
6. Services on dead end streets can be con-
sidered as services on the street segment that
they intersect, since they can only be collected
by passing down that street segment. To keep
left turns at a minimum, collect the dead end
streets when they are to the right of the truck.
They must be collected by walking down, back-
ing down, or making a U-turn.
7. When practical, steep hills should be col-
lected on both sides of the street while vehicle
is moving downhill for safety, ease, speed of
collection, and wear on vehicle, and to conserve
gas and oil.
8. Higher elevations should be at the start of
the route.
9. For collection from one side of the street
at a time, it is generally best to route with many
clockwise turns around blocks.
Heuristic rules 8 and 9 emphasize the devel-
opment of a series of clockwise loops in order
to minimize left turns, which generally are more
difficult and time-consuming than right turns
and, especially for right-hand-drive vehicles,
right turns are safer.
10. For collection from both sides of the street
at the same time, it is generally best to route
with long, straight paths across the grid before
looping clockwise.
11. For certain block configurations within
the route, specific routing patterns should be
applied.
what routing
patterns
should be applied?
As the router gains experience, he will recognize
routings that are efficient for certain block pat-
terns. Certain patterns should be considered
whenever the grid has blocks arranged as
shown in the figures (Figures 3 through 7).
Sequential application of these patterns helps
-------
START
«*•
Figures. Specific routing pattern for one-way street, one-side-of-the-street
collection. In this pattern, collection is made from both sides of the one-way
street during the pass. For wide or busy one-way streets, it is necessary to loop
back to the upper end and make a straight pass down the other side.
-------
1
STAR
FINIS
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COLLECTION
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FINISH
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BOTH SIDES OF
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DIRECTION OF ONE-WAY STREETS
Figure 4. Specific routing patterns for multiple one-way streets. Note the
one-way streets are paired with a clockwise movement.
-------
START •-
FI N PS H. •
FOUR-BLOCK CONFIGURATION APPLICABLE WHEREVER
FOUR BLOCKS ARE POSITIONED AS SHOWN
THREE-BLOCK CONFIGURATION
START*.
FINISH*
START
FINISH
VARIATION OF THREE-BLOCK CONFIGURATION
VARIATION OF THREE-BLOCK CONFIGURATION
Figure 5. Some specific routing patterns for three- and four-block configura-
tions. In all configurations, blocks may vary in size and shape.
-------
START
FINISH
4x4 BLOCKS
NO LEFT TURNS
NO DEAD DISTANCE
START
FINISH
4x6 BLOCKS
ONE LEFT TURN
NO DEAD DISTANCE
Q
n
a-a
n
•a
n
a
D a
E
a
6x8 BLOCKS
ONE LEFT TURN
NO DEAD DISTANCE
START FINISH
Figure 6. Combinations of the four-block pattern, one-side-of-the-street collec-
tion. Note that each route is started midway on an evenly divided side of the
grid, and uses the same routing pattern, with progression in a counter-clockwise
fashion. For the larger grids, once the outside is routed the inside is routed in a
clockwise progression.
10
-------
START
FINISH
PAT TERN A
FINISH •
PATTERN B
Figure 7. In specific routing patterns for both-sides-of-the-street collection,
pattern A entails no left turns, and pattern B requires nine left turns. Dash lines
represent "dead distance" or non-collection segments of the route.
11
537-034 O - 74 - 3
-------
yield efficient route layouts. After determining
which street segments have services and which
are without services, applying these patterns
and developing additional patterns for an ef-
ficient route is relatively simple.
To help simplify the problem, a grid simpli-
fication technique, described in the section
"Routing, How Is It Done?" may be applied be-
fore looking for block patterns.
*
how are the
heuristic rules
applied?
The heuristic rules are guides which, used in
conjunction with the patterns, help determine
the vehicle path or route. Because of the infinite
possibilities of street and block arrangements
and routing patterns, a rigid procedure for rout-
ing cannot be applied and thus routing does not
lend itself well to being programmed for a
computer.
In applying the heuristic rules and patterns,
the router should look ahead and behind sev-
eral street segments and ask himself these
questions:
• Do any of the heuristic rules apply here?
Are they being violated?
• Have any street segments been left behind
that will require a long dead distance to re-
turn and pick up?
• Are there already some long dead distances
that might be reduced through slight modi-
fications?
• Are there any peculiar or unique character-
istics of the area which should be considered?
• Are there any patterns that can be utilized
in the routing?
Once the initial layout has been determined,
it should be reviewed for further refinements.
The route should be retraced and alternate
routings or modifications should be attempted
wherever long dead distances are apparent.
Note, however, that to evaluate all possible
routing alternatives is a formidable task that
even computer models do not attempt.
In summary, the heuristic rules and patterns
facilitate the routing process, but must be tem-
pered with a commonsense application and ex-
amination as the route is being developed.
12
-------
what preparations
are needed for
routing?
In developing on efficient collection system,
micro-routing as defined here is actually the
last of four tasks that might precede implemen-
tation. In order, these tasks are:
• Review and evaluation of existing policies
and methodologies
• Macro-routing
• Districting and route balancing
• Micro-routing
• Implementation
A major tool that will assist in all of these
tasks is a management information system
(MIS) based on a daily collection activity re-
port. The MIS. includes route, collection, and
cost information records that help identify time
and cost centers. A report entitled Management
Information System for Residential Solid Waste
Collection provides further detail.2
Collection policies and methodologies directly
affect routing and collection efficiency and
should be reviewed, evaluated, and changed, if
necessary, before rerouting proceeds. This kind
of analysis is discussed fully in a report entitled
Policies and Methodologies for Solid Waste Col-
lection.3 Policies, which primarily relate to
levels of service, include:
• Point of collection (distance from street to
storage)
• Freguency of collection
• Type and weight limits of storage device
• Garden waste collection
• Bulky waste (furniture, white goods) collec-
tion
• Separate versus combined collection
Methodologies, or on-the-route practices, in-
clude :
• Crew size
• Type and capacity of collection vehicles
• Shuttle system
• Reservoir system
• One-side versus two-sides-of-the-street collec-
tion
• Fixed lunch site and time
• Collection by drivers
• Incentive schemes
• U-turns and vehicle backing
• Filling vehicles before going to disposal site
After policies and methodologies have been
reviewed and revised and the collection areas
have been assigned to disposal facilities (macro-
routing), districting and route balancing must
be performed. The key to districting and route
balancing is determining a fair day's work—
the reasonable number of services each day
for each collection area. Calculating a fair day's
work reguires at least a sound estimate of the
average time spent to service a residence and
the amount of waste collected at the residence.
These figures can be used to derive the average
number of residences that can be serviced for
each service area, the number of routes re-
guired, and the size of each route to egualize
workloads. The route balancing process is de-
scribed more fully in a report entitled Disfricfing
and Route Balancing for So/id Waste CoJ7ecfion.4
Once the equitable service numbers for each
route are determined, the community is first
divided into districts—one for each collection
day in the week. Districts also should conform
to manmade and natural barriers such as major
streets, railroads, expressways, parks, rivers,.
lakes, gulleys, and mountains. Each district
then is divided into routes—one for each collec-
tion crew.
Micro-routing is performed after districting
13
-------
and at the same time the balanced routes are
developed. For example, once the service area
for Monday is defined, the micro-routing pro-
cedure is applied in a clustered area until the
predetermined number of services is developed
into a route. Then the next route is developed
starting in the area which is still unrouted. This
procedure continues until the whole city is
routed. As the routing process continues, how-
ever, the originally selected districts may have
to be modified to achieve more efficient routings.
what data
are required
for routing?
All the information required for routing can be
recorded on community maps. First, indicate on
the community map(s) the number and type
(residential, apartment, commercial, institu-
tional, industrial) of services per street segment
for each side of the street. The remaining street
segments with no services on them are non-col-
lection segments. Next, identify all one-way,
dead end, and heavily traveled streets. Indicate
which corner-lot residents (if any) should be
asked to place their waste on a specific street
segment. Finally, indicate, for each street seg-
ment or service area, whether the crews are to
collect one or both sides of the street on a pass.
routing,
how is it done?
To help simplify the routing problem, it is often
helpful to reduce the grid by applying a grid
simplification technique (Figure 8). By this
method, the number of blocks in the grid are
reduced by combining blocks that have no serv-
ices on the common street segments which face
each other. The pattern and routing procedure
can then be applied to this simplified grid. Also,
by getting certain corner-lot residents to place
their wastes on specific streets, it may be pos-
sible to eliminate the need to traverse the ad-
joining street. By encouraging neighboring
residents to place their wastes together, the
collection time can be speeded, and just as im-
portant, the stop-and-go wear on the vehicle
will be reduced thus extending its life.
Using the marked map, pick a starting point
and link the street segments in each district into
a continuous route by applying the heuristic
rules and patterns to systematically minimize
the dead distance and left turns. Terminate the
route when the number of services is about that
determined to be reasonable for a fair day's
work.
Determine the starting point for the next route
and repeat the routing procedure, again apply-
ing the heuristic rules and patterns until all the
services within the district have been routed.
Continue until all districts have been routed. As
with districting, the service boundaries for each
route should be determined by considering nat-
ural and manmade boundaries.
For areas with significant seasonal fluctua-
tions in waste generation, the most common
solutions are to increase the crew sizes, extend
the work day (pay overtime), or add a crew
to the reservoir area for peak periods. Another
alternative is to shorten each route (i.e., lessen
the collection task) and add crews. This kind
of adjustment can be readily accomplished in
two ways: (1) by designing one continuous
collection route for each day of the week or area
and then assigning crews to distinct sections of
the continuous route based on the previously
determined number of services per route; or (2)
by establishing different routes for each season
of the year. The second method is generally the
better of the two.
14
-------
CD
O
CO
Dept.of Public Works
-\-
Figure 8. Grid simplification technique. Blocks with no services on common
street segments are combined before routing. All of the daily grids in the
Huntington Woods example in this report are easily simplified by this technique.
This figure shows the Friday route.
15
-------
In the pattern method of routing, the first step
is to identify the garage and disposal site loca-
tions, heavily traveled streets, one-way streets,
and street segments with services (Figures 9
and 10). The garage location is shown on each
example, and for simplification, assume no
heavily traveled or one-way streets exist and
all street segments have services on them.
The next step is to identify block patterns and
pick a starting point nearest the garage. In the
four- and three-block patterns, the solution is
obtained by connecting the patterns together as
well as possible through a trial-and-error (heu-
ristic) process (Figure 9).
In the 4X4 combination of the four-block con-
figuration, and variations of the three-block
configuration, again the solution is obtained
through a trial-and-error process of connecting
the patterns into a continuous route (Figure 10).
GARAGE
SAMPLE
PROBLEM
GRID
Figure 9. Example showing pattern method of routing. This solution has no
dead distance and two left turns.
16
-------
GARAGE
PATTERNS
IDENTIFIED
;
GARAGE
••— ^
START V...
FINISH
i
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j
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j
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'
PATTERNS
CONNECTED
INTO CONTINUOUS
ROUTE
Figure 9. Example showing pattern method of routing. This solution has no
dead distance and two left turns.
17
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GARAGE
GARAGE
GARAGE
SAMPLE PROBLEM GRID
PATTERNS IDENTIFIED
Figure 10. Example showing pattern method of routing. This solution has no
dead distance and 10 left turns.
18
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The way in which change is implemented is,
of course, as important as the evaluation and
design phases that precede it. People generally
resist change, even if it is beneficial. A good
public education program must, therefore, be
developed and tactfully applied to reduce this
natural resistance.
As with most alterations in a solid waste col-
lection system, a change in routing affects at
least three groups of people: (1) the solid
waste management team, (2) the solid waste
collectors and drivers, and (3) the public. A
public education program should properly in-
form each of these groups about what is ex-
pected of them and enlist their cooperation.
The first group involved in rerouting and other
system changes is the solid waste management
team. The heuristic approach is designed for
the solid waste managers and supervisors to
apply. Their participation in the routing serves
several purposes. First, it is apt to make them
feel that the new system is their system and
thus obtain their inherent support. Second, mem-
bers of the solid waste management team are
generally the persons, who, besides the col-
lectors themselves, are most familiar with the
service areas and are thus best qualified to
perform the routings. And third, management,
including supervisors or foremen, must be fa-
miliar with the new routings and other changes
for supervisory, planning, and control purposes.
The solid waste collectors and drivers should
be informed of all proposed changes to the col-
lection system and encouraged to comment on
the effect of the changes on their daily opera-
tions. Their criticisms or suggestions for further
improvement are essential to the final evalua-
tion by the management staff. In addition to
being a potential source of pertinent input, the
workers' participation in reviewing the decisions
may be a useful managerial tool in that it helps
them feel a part of the new system.
Several mechanisms can elicit cooperation
from the collection personnel and ameliorate
employee morale during and after implementa-
tion. Unless wages are already rather high, an
increase may be considered in light of the
increase in productivity (increased services per
hour). Or the increased productivity may be
rewarded by a new incentive system .e.g., the
task system versus the straight 8-hour day.
To orient drivers to the new routings, each
should be given a personal notebook contain-
ing a map of each daily route which he may
review and use during collection. Examples of
the maps are shown for the City of Huntington
Woods in the next section. The supervisor should
retain a file copy of the route notebook.
Increased efficiency, almost by definition,
means that fewer collectors will be required.
It also means that more services will be col-
lected per hour. These two factors, plus an
understanding of the local labor relations situa-
tion, must be considered in determining when
to notify collectors of a proposed change in
their system, in presenting the change posi-
tively, and in deciding if the collectors will
assist in rerouting. Often, however, increased
productivity can be achieved with a reduced
labor force but, at the same time, a reduced
workload for the remaining collectors.
Citizens are directly affected by changes in
the day and time of collection, the point of col-
lection, the frequency of collection, or the type
of storage device. In designing a new system,
it is usually a good idea to minimize the num-
ber of citizens who will have to change their
day of collection, as demonstrated in the Hunt-
ington Woods rerouting example. These citizens
must be notified of their new collection day and
lot residents should also be notified if they are
the date the change will take place. All affected
corner-lot residents should also be notified if
19
537-034 O - 74 - 4
-------
they ore to place their waste on certain streets.
All citizens in the community—even those
whose collection day will not change—should
be informed that the solid waste collection serv-
ice is being altered. Residents often become
accustomed to collection at a specific time of
day and may set their waste out accordingly, or
frequently they relate their own time of collec-
tion with that of their neighbors across the
street or around the corner, which may have
changed. Thus informing everyone should mini-
mize missed collections.
City officials also should be apprised of the
proposed changes. Persuaded of these changes,
they often are important allies during the transi-
tion. Too, should they be approached by citi-
zens regarding the changes, they should be
aware of what is taking place.
The most extensive education effort will be
directed toward the citizens. Several media are
available. One of the best is a: letter from the
mayor or city manager explaining the reasons
for the changes and how the changes may
affect the citizens. Such a letter uses a soft-sell
approach, implies endorsement by the city man-
agement for the new system, and may include
a telephone number to call for further informa-
tion (Figure 11).
Another good way to notify the citizens is
through flyers (Figure 12). The letter and flyers
shown here are similar to those used in Kansas
City, Missouri, during their effective implemen-
tation program for a change that took place in
March 1971. Note that the flyer is simple, yet it
gives all pertinent information. The map helps
residents conceptualize the collection area and
acts as a check to assure that the flyer was
delivered in the correct area. In Kansas City,
the actual cards were color-coded by day of
the week to assist in answering phone inquiries
from the citizens.
Other methods that can effectively inform the
public include television and radio announce-
ments and articles and notices printed in local
newspapers. Even with an initial multifaceted
information program, complete citizen under-
standing and cooperation requires time and
patience. Interpersonal contact may be bene-
ficial: e.g., (1) extra office personnel and per-
haps extra telephone extensions to receive
complaints and questions during the change-
over; or (2) personal interviews with specific
corner-lot residents. Finally, using savings as
they accrue from the new collection operations
to upgrade the cleanliness and appearance of
the trucks, replace unreliable trucks, provide
uniforms for the collectors, or improve the dis-
posal situation certainly helps sustain good
public acceptance.
The next section is .a step-by-step account of
how the heuristic routing procedure was per-
formed in one of many communities that have
recently adopted this approach.
20
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Office of the Mayor
Julius C. Jones, Mayor
City of Anytown, USA
Heart of America
30th Floor, City Hall
Anytown, USA 64106
February 12, 1973
Councilman at Large
Joseph Hall
1st District
James Smith
2nd District
William Glenn
3rd District
Thomas Rose
4th District
Mark Jones
5th District
Paul Hogan
6th District
District Council men
Robert Phillips
1st District
Charles Connolly
2nd District
Alan Michaels
3rd District
Peter Bobbins
4th District
William White
5th District
James Myers
6th District
Dear Citizen:
On Monday, March 5, 1973, we will introduce a new City-wide refuse collection system designed to
decrease the City refuse budget while still providing the same level of service to you, the citizens.
This savings is made possible through the thorough evaluation of our refuse collection system using
the latest of management tools and implementing improved collection techniques.
The collection service will continue to be once-a-week curbside collection. We have, however,
revised the City ordinance to permit the use of plastic sacks, which we encourage you to use. En-
closed is a brochure explaining the advantages to you and to the City through the use of plastic
sacks, and some helpful hints on bag usage and refuse storage.
The only change affecting the citizens directly is a change for some in their day of collection. We
have tried to minimize the number of citizens that must change their day of collection. This new
collection system means, however, that in most instances the time of day that the collectors collect
from each residence will change. The enclosed map shows the day of collection for each area. Please
note when your new day of collection will be starting March 5.
Please help our sanitation men provide service to you during this change-over by having your waste
put out by 7:00 a.m., the time they start to collect.
If you have any questions or suggestions, please call 684-4311.
Thank you for your cooperation in this effort.
Sincerely,
Julius C. Jones
Mayor
Figure 11. Sample letter from a mayor to citizens notifying them of a change in
collection system.
21
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Important Notice
Beginning March 5, 1973
Your New Refuse Collection Day will be
tuesday
There will be no collection on
the following holidays:
May 28, 1973
September 3, 1973
October 8, 1973
October 22, 1973
December 25, 7973
February 78, 7974
If a holiday is observed on Monday or
Tuesday, your collection day for that
week will be WEDNESDAY.
For information call 254-7417
39th
38th
63rd St.
Public Works Department
Refuse Division
Anytown, U.S.A.
Important Notice
Beginning March 5, 1973
Your New Refuse Collection Day will be
Wednesday
There w/H be no collection on
the following holidays:
May 28, 1973
July 4, 1973
September 3, 1973
October 8, 1973
October 22, 1973
December 25, 1973
February 18, 1974
If a holiday is observed on Monday,
Tuesday, or Wednesday, your collection
day for that week will be THURSDAY.
For information call 254-7417
63rd St.
Public Works Department
Refuse Division
Anytown, U.S.A.
Figure 12. Flyers are effective media for informing citizens of changes in
collection system.
22
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The Office of Solid Waste Management Pro-
grams assisted the City of Huntington Woods,
Michigan, in applying a heuristic approach to
rerouting its solid waste collection vehicles. This
section briefly characterizes the community's
existing collection system at the time study was
initiated and its new collection system, and
traces the development of its new collection
routes.
Huntington Woods is a middle-class subur-
ban community just outside Detroit. The popula-
tion (1970 census) is 8,536, which represents
2,497 residences. From solid waste disposal rec-
ords the average solid waste generation rate
.was estimated to be about 1.3 kg (2.9 Ib) per
capita per calendar day, or an average of about
31.5 kg (70 Ib) of solid waste each week from
each residence. Seasonal variations in the
amount of solid waste, which must be consid-
ered in designing an efficient collection route,
were also determined before the rerouting
study.
evaluating
existing policies
A thorough review and evaluation of the city's
existing solid waste collection policies provides
the basis for a "before and after" comparison
that reflects the increased efficiency of collec-
tion system operations. Under both the former
and the new systems, the city provides weekly
curbside collection service to all residents and
to the city's few commercial services. About 80
percent of the city's residents use plastic bags
for waste storage. The city's collection system
formerly used two 12.2-cu meter (16-cu-yd),
rear-loading packer trucks operated by two two-
man crews to collect one side of the street at a
time.
The Huntington Woods city management per-
sonnel considered a rerouting program neces-
sary because they had acquired new collection
equipment. The city had purchased a one-man,
side-loading collection vehicle to replace one of
the older rear-loading packer trucks. During a
trial period, the replacement was able to finish
the collection routes in approximately 5 hours.
Thus, although the city had saved the equiva-
lent of 1 man-year in labor costs, the potential
for even greater savings through rerouting ap-
peared very promising.
compiling the data
The data required for rerouting the City of Hunt-
ington Woods included a series of three maps.
The first, prepared by the superintendent of the
Department of Public Works, was a detailed
street map of the city showing the number of
residential services for each street segment
(Figure 13). Note that it is important to cor-
rectly identify the number of services on each
side of a particular street segment and the lo-
cation of the Department of Public Works ga-
rage or motor pool. A separate city map was
prepared to identify all one-way, heavily trav-
eled, and dead end streets (Figure 14).
A third map identified those street segments
where no waste would be placed for collection,
i.e., undeveloped segments with no services
and corner-lot residences that do not face the
street (Figure 15). By correctly designating
these segments, they can be eliminated from
the design of the collection route and thus help
23
-------
minimize the dead distance in the individual
routes. In Huntington Woods, many such street
segments were identified by asking residents
of corner lots to place their waste on a specific
street segment (though in most cases the cor-
ner-lot houses faced the desired street ^segment
and the waste was already being placed there).
Figure 16 shows the former collection routes
before rerouting and a breakdown of service
areas by day of the week. A comparison of
each truck's daily workload shows definite im-
balances between the two trucks and in the
general workload from day to day, even though
service density and the amount of waste per
service are similar for each route (Table 2).
On Monday, for example. Truck No. 1 serviced
281 residences and Truck No. 2 serviced 305
residences, a total of 586 services. On Friday,
however, these same trucks collected 131 and
183 residences, respectively, a total of only 314
services. The old collection routes were frag-
mented; the Wednesday and Thursday collec-
tion routes, for example, are typical of both
fragmented and unbalanced routes that most
likely evolved with the development of the com-
munity (Figure 16 ).
reviewing existing
and alternative
operations
At this point in the rerouting study the city
reviewed its existing collection system opera-
tions and identified possible alternatives. The
city management isolated four major areas of
the collection operation where possible alter-
natives existed. The areas, along with the alter-
natives, were:
1. Equipment
Side-loader, 22-cu-rneter (29-cu-yd),
(one available)
Rear-loader, 12.2-cu-meter (16-cu-yd),
(two available)
2. Crew size
One-man, side-loader only
Two-man, driver and one collector
Three-man, driver and two collectors
3. Level of service
Curbside, once a week
Carryout, once a week (requires additional
personnel)
TABLE 1
SEASONAL VARIATIONS IN SOLID WASTE COLLECTION
CITY OF HUNTINGTON WOODS, MICHIGAN
Solid waste to be collected
Season
Average wt/day
Average wt/ reiiidence/wlc
^
Winter
Spring
Summer
Fall
tonnes
10.6
15.0
18.2
19.2
tons
11.8
16.7
20.2
21.3
kg
21.2
30.1
36.4
38.3
Ib
47.2
66.8
80.8
85.2
TABLE 2
HESIDENCES SERVICED BY DAY OF WEEK AND TRUCK
Residences serviced
Vehlclo
Truck No. 1
Truck No. 2
TOTAL
Mon.
281
305
586
Tues.
289
267
556
Wed.
220
328
548
Thur.
323
170
493
Fri.
131
183
314
Daily
Average
248.8
250.6
499.4
24
-------
AVMH3IH 33011000
ir
Figure 13. Detailed community map of Huntington Woods, Mich., showing
services per street segment.
25
-------
X-X- ftXtt!:j:.-X:X:X;:;X:X;:;:;-X*^
A.VMHOIH aaa nooa
Figure 14. Detailed community map showing special streets.
26
-------
Dept.of Public Works
n>
i-"
01
3
f
I
s
No homes face these
streets (other than
corner lot residences)
SCALE OF MILES
to
SI
-------
AVMHDIH
Figure 16. Former collection routes.
28
-------
4. Collection methodology
Collection from one side of street
Collection from both sides of street
Plastic bags as mandatory storage
containers
The city management felt that the existing
level of service (curbside, once a week) and
collection policy (collecting from one side of
the street and voluntary use of plastic bags)
was the best of the alternatives considered. With
respect to equipment and crew size, the city
management wished to fully utilize the new one-
man collection vehicle and collect any remain-
ing waste using a rear-loading packer truck
with a two-man crew. Thus the collection sys-
tem was defined by the city, and all that re-
mained was the design of the collection routes.
Some additional data were required before
the actual heuristic routing could be started.
The average round trip time to the disposal site,
average time per service, average number of
services per street mile, and average weight
per service are all important parameters in the
design of any efficient collection route and can
be obtained by using a daily collection activity
report. In Huntington Woods, the average round
trip time to the disposal site is 45 minutes; the
average time per service during peak generation
periods is 0.5 minutes and the average weight
per service during the peak generation period
is 38.2 kg (85 Ib) per residence per week.
To determine the total number of collection
routes required, the total number of residences
(2,500) was divided by 5 (maximum number
of possible collection days), which resulted in
a daily workload of 500 services. Thus, using
an average 0.5 minutes per service, an average
of 250 minutes per day, or about 4.25 hours per
day, would be required to collect waste from
500 residential services during the peak season.
The low collection time of only 0.5 minutes per
service is largely due to the use of plastic bags
by 80 percent of the residents. One-way bags
reduce collection time per service.
Using the peak solid waste generation rate of
38.2 kg (85 Ib) per residential service, the total
weight collected from 500 services should be
about 19.12 tonnes (21.25 tons) per day. The
city's one-man collection vehicle has a 22-cu-
meter (29-cu-yd) capacity which can handle
payloads of up to 7.2 tonnes (8 tons) or 326
kg/cu meter (550 Ib/cu yd). Thus during the
peak season, with an average of 19.2 tonnes
(21.25 tons) of solid waste to be collected and
a collection vehicle with an average payload
of 7.2 tonnes (8 tons), three trips to the disposal
site are required. At the average 45 minutes per
trip, the total time required for three trips to the
disposal site is 2.25 hours per day.
The city policy allows two 15-minute coffee
breaks per day and a 30-minute lunch period.
The lunch break is not paid time and can be
taken at the convenience of the collector. Times
are apportioned for the various activities of the
collection operation, based on 500 services per
day and the one-man collection vehicle (Table
3). The 1-hour variance allows for day-to-day
variations in waste generation, unusual delays
at the disposal site, and adverse weather con-
ditions. From the data analysis, the solid waste
collection routes for the City of Huntington
Woods should be designed to include approxi-
mately 500 residential services per route.
determining the
new routes
Because the number of services per collection
route is the single most important parameter in
designing an efficient collection route, at this
point in the routing study the extrapolated aver-
age number of services should be verified. In
Huntington Woods, the existing Wednesday
collection routes serviced 548 residences; there-
fore the two were combined and selected as a
test route for the one-man collection vehicle. All
548 residences were adequately serviced in less
than the 8-hour work day. Thus the proposed
500 services per route appeared to be a very
reasonable workload for the new collection sys-
tem configuration.
The City of Huntington Woods was rerouted
manually using the heuristic approach (Figure
17). A comparison of past and present collec-
tion routes dramatically depicts the changes in
service areas by day of the week and route
assignment (Figures 16 and 17). A comparison
of the performance of the former collection sys-
tem and the new rerouted collection system
shows that Truck No. 2, a rear-loading packer
29
-------
truck, has been completely eliminated and that
Truck No. 1, the one-man collection vehicle, is
servicing the entire city (Table 4). The new
collection routes are continuous, balanced, and
not fragmented or overlapping.
New street-by-street collection routes were
developed for the Monday through Friday serv-
ice areas (Figures 18 through 22). The previ-
ously outlined heuristic rules and patterns, and
a systematic approach were the basis for the
design of all the collection routes. Note that
since the route is continuous, the collector may
leave the route for a trip to the 'disposal site
whenever his vehicle is fully loaded and simply
return to the point of departure to continue
collection.
implementation
considerations
Successful implementation of the proposed col-
lection routes depended upon securing the sup-
port of the collection personnel and the citizens
of the community.
The collection personnel were directly in-
volved in and contributed to the rerouting study
by providing much of the required data and by
reviewing the proposed changes. The collector
was given a complete route book graphically
describing the service area for each day of the
week and street-by-street routing of his vehicles
(Figures 18 through 22). The added respon-
sibility of operating the new one-man collection
vehicle and the increased number of services
justified a wage raise. Displaced collection per-
sonnel were reassigned to other areas of the
Department of Public Works.
To balance the service areas into egual work-
loads, only simple changes in the service area
boundaries were required, thus minimizing the
areas of the city where the day of collection was
changed because of rerouting (Figure 23).
Only 275 residences, or about 11 percent of the
total residences in the city, were affected by a
change in the day of collection. A letter from
the office of the city manager informed these
residents of the change in collection day and
requested their cooperation.
TABLE 3
TIME REQUIRED FOR VARIOUS COLLECTION ACTIVITIES
Activity
Average time required
(hr)
Collection
Disposal
Coffee break (2)
Variance
4.25
2.25
.50
1.00
TOTAL
8.00
TABLE 4
RESIDENCES SERVICED: OLD AND NEW COLLECTION ROUTES
Residences serviced
Route
Mon.
Tues.
Wed.
Thur.
Fri.
Former collection routes:
Truck No. 1
Truck No. 2
TOTAL
281
305
586
289
267
556
220
328
548
323
170
493
131
183
314
New collection routes:
Truck No. 1
Truck No. 2
TOTAL
500
0
500
492
0
492
494
0
494
517
0
517
494
0
494
30
-------
AVMH9IH 39011003
Figure 17. New collection routes.
31
-------
\
Tt
FINISH
START
Figure 18. Monday collection route: 500 residences; five left turns.
32
-------
Figure 19. Tuesday collection route: 492 residences; six left turns.
33
-------
FINISH
I 15 f \ \3~~ I
I " I I ta |
•n
GOLF COURSE
"START
Figure 20. Wednesday collection route: 494 residences; one left turn.
ELEVEN MILE ROAD
D
D
H
D
:
i
li
1
1
14
KINGSTON 17
17
LA SALLE is
15
BORGMAN 16
T6
TALBOT 15
fc 114
\ HART is
1 \
\
START
1 1
16
17
16
, 14
1 5
1 5
16
1 1 4
I * 5
5
L :"
8 I
16 1
16 -1
16 ij
1 6 :
1 6 :
1 6 \j
16 J
I 16 / j;
4 t:
/ a
' / i
FINISH |
i
4
1 1
14
1 1
17
5
l^^MBM
6
1 1
-y
*,,
0
1—
C9
z
12^
a:
14
"I
'/
/ i
7
1 rn »-
Figure 21. Thursday collection route: 517 residences; five left turns.
34
-------
Dept.of Public Works
FINISH
JSTART
:VEN MILE ROAD
LINCOLN 8\
VERNON 7
Figure 22. Friday collection route: 494 residences; 16 left turns.
35
-------
r
AVMHDIH 33011003
36
Figure 23. Area of Huntington Woods in which the day of collection was
changed because of rerouting.
-------
effectiveness of the
micro-routing
program
Because micro-routing is the last system design
step in the five-stage improvement process and
other changes usually take place at the same
time, it is difficult to isolate how much of the
resultant savings are attributable solely to
micro-routing.
In the case of Huntington Woods, for example,
three separate changes ensued. First, in 1970,
two three-man crews were reduced to two two-
man crews. Then, in August 1971, these crews
were further reduced to one two-man crew and
one one-man crew. Soon thereafter, the heu-
ristic routings were designed for the one-man
crew with the two-man crew being eliminated.
However, one of the two-man crew was retained
as a spare as explained below. The total work
force therefore was reduced from six to two
men; the number of collection vehicles was re-
duced from two to one.
Since only the last of the three changes was
achieved predominantly through the heuristic
routings, the effectiveness of the heuristic rout-
ing program is measured by the reduced costs
to the City of Huntington Woods from this third
change.
From 1971 to 1972 the average hourly labor
wage increased from $4.42 to $4.77, or 7.9 per-
cent, and the total tonnage collected increased
from 3,886 tor^ies (4,318 tons) to 4,062 tonnes
(4,513 tons), or 4.5 percent. But the total labor
charges decreased from $31,309 to $23,700, or
24.3 percent. These labor costs reflect the elim-
ination of one man on the two-man crew, since
one individual was retained to fill in for vaca-
tions, etc., and for street sweeping and a new
separate collection of newspapers. Since the ,
change occurred in the fall of 1971 to distort
the 1971 figure, the actual savings in total labor
wage reflects a 28-percent reduction, from
$32,738 to $23,700. Over the 3-year period, of
course, the total savings to Huntington Woods
have been much higher.
The effort involved in rerouting the City of
Huntington Woods was minimal in view of the
cost reductions. The public works superintendent
reported that he spent "one day off and on"
gathering the required information. The authors
of this report spent one day (two man-days)
designing the routes and preparing the route
book showing each service area and route. The
total effort was less than three man-days.
37
-------
To see modem scientific management tech-
niques applied to solid waste management sys-
tems is encouraging. Yet, in the case of micro-
routing, a less sophisticated, common-sense
approach—the heuristic approach—often is suf-
ficient. This approach has the advantage of
being a simple tool that can be readily learned
and applied by local operating personnel. In
addition, it avoids the high cost of existing com-
puter models and gives more flexibility to the
routing—a necessity, since communities and
routes are so variable. The use of computers or
computer models is not to be discredited. Com-
puters have proved useful to solid waste man-
agement for billing systems, for storing and
manipulating information ([the Management In-
formation System for Solid Waste Collection,
for example), and for models for more complex
procedures such as macro-routing.
The major problem in routing today is that
very few communities or collection agencies
have ever studied their routings and attempted
to improve them. Now that a straightforward,
heuristic approach has been developed, more
communities can pursue the lower costs and
better service that potentially exist for them.
Huntington Woods was a forerunner, but
other communities have since used the heuristic
approach to routing their solid waste collection
vehicles:
Akron, Ohio
Beverly Hills, Mich.
Birmingham, Mich.
Clawson, Mich.
Des Moines, Iowa
East Peoria, 111.
Fall River, Mass.
Flint, Mich.
Hot Springs, Ark.
Huntsville, Ala.
Lathrup Village, Mich.
Little Rock, Ark.
Portland, Maine
Royal Oak, Mich.
St. Petersburg, Fla.
Each of these cities has realized substantial
savings or increased the level of service. Again,
not all of the savings" necessarily can be at-
tributed to the heuristic routing alone.
Experience is the best teacher of routing pro-
cedures. To provide some practice for the reader,
this section contains three exercises to familiar-
ize the prospective router with the heuristic
routing techniques. See Figures 24, 25, and 26;
each figure is a map that includes all the neces-
sary information and instructions to develop
a route. Figure 24 shows a simple block con-
figuration for one route; Figure 25 shows the
same block configuration complicated by two
one-way streets. Figure 26 shows a complex
street layout covering two routes. Figures 27
through 29 present solutions to the exercises.
38
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7
3 2
8
8
3 5
8
5
16 17
6
9
3 1
8
10
2 2
11
2
18 20
3
6
4 3
5
I 7 I
12 l|
I 8 I
9
5 6
8
7
4 2
8
5
1 2
6
7
2 1
7
6
I 1 1
1 7
8
4 3
7
9
2 1
8
10
2 1
10
GARAGE
Figure 24. Exercise example: 373 residences; two-way streets.
39
-------
7
3 2
8
8
3 5
8
5
16 17
6
g
3 1
8
10
2 2
11
\
>.
2
18 20
3
6
4 3
5
7
2
8
i.
g
5 6
8
7
4. 2
8
> •*
ui
z
o
5
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6
7
2 1
7
6
1 1
7
z
0
1
8
4 3
7
g
2 1
8
10
2 1
10
GARAGE «START
Figure 25. Exercise example: 373 residences; one-way streets.
40
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Figure 26. Exercise example: 997 residences; two collection routes.
41
-------
START
10
FINISH
I GARAGE
T8
17
Figure 27. Solution to exercise example, Figure 24. Includes 6 left turns, no
dead distance.
42
-------
7
• 3 2
8
1 < >.
8
. .3- 5
8
\.
5
. 16 17
6
I ^
9
k 3 1
8
n — * — '
110
•2 2
11
*
. ^
/
S,
„ J
f
>
0)
S'
,
'
< 1
t
2
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3
6
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5
4 >_
5
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6
*
7
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7
6
1 1
7
*-. _
•r
\
r •
0
V
0
f t
r •
r '
r
7
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8
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9
,5 6 -
8
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7
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8
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8
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7
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8
c \
10
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10
• — t — -
• GARAGE
Figure 28. Solution to exercise example, Figure 25. Includes 14 left turns; dash
lines represent dead distance.
43
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ROUTE 1: 488 RESIDENCES, 17 LEFT TURNS.
ROUTE 2: 509 RESIDENCES, 17 LEFT TURNS.
CAN START AND FINISH AT
EITHER POINT A OR B.
Figure 29. Solution to exercise example, Figure 26. Route 1 serves 488
residences; route 2 serves 509 residences. Each entails 17 left turns.
44
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Shuster, Kenneth A. and Dennis A. Schur. Heuristic flouting for Solid
Wasfe Collection Vehicles, U.S. Environmental Protection Agency,
1974.
The development and successful application of a heuristic procedure
for routing solid waste collection vehicles is described. Topics include
(1) the value of routing, (2) reasons for rerouting, (3) advantages of
the heuristic approach, (4) heuristic rules, data requirements, and rout-
ing procedures, (5) factors to consider when implementing this ap-
proach. An actual example and exercises are included to show the rela-
tive ease of application and to familiarize the reader with the heuristic
approach to the routing of solid waste collection vehicles.
V0856
1. Bowman, E. H., and R. B. Fetter. Analysis for production and opera-
tions management. 3d ed. Homewood, 111., Richard D. Irwin, Inc.,
1967. p. 452.
2. Shuster, K. A. Management information system for residential solid
waste collection. (In preparation.)
3. Shuster, K. A. Policies and methodologies for solid •waste collection.
(In preparation.)
4. Shuster, K. A., and D. A. Schur. Districting and route balancing for
solid waste collection. (In preparation.)
U. S. GOVERNMENT PRINTING OFFICE : 1974 O - 537-034
45
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