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APPENDIX A
LITERATURE REVIEW
State truck weight enforcement agencies generally measure their accomplishments in teens
of actual enforcement activity, i.e., the number of trucks weighed, legalizations, etc. However, these
measures can not address actual weight violation activity, i.e. number and severity of actual on-road
overweight truck traffic. As a result, truck weight enforcement agencies currently have no way of
gauging the real problem of overweight truck activity.
The objective of this literature search is to examine documented studies addressing relevant
issues related to truck weighing effectiveness, i.e., potential in situ truck weight data sources and
appropriate data-gathering technologies, required to establish a program for monitoring truck weight
enforcement impacts.
BACKGROUND
Genera/ Truck Weigh! Enforcement Effectiveness
Ding He late seventies, the U.S. Government Accounting Office sent a questionnaire (~)
to all states asking for information on truck weight laws, enforcement programs and methods, and
background data on their State Highway System. The final report, summarizing the states'
responses, referred to enforcement program effectiveness only in terms of numbers of trucks
weighed and citations issued.
A 1981 NCHRP Synthesis (2) addressed criteria for evaluating truck weight enforcement
programs. Various findings are cited as follows:
i. One purpose of truck weighing programs is to enforce legal load limits and to prevent trucks
from damaging highways and bridges. Although all states have truck weight enforcement
1
Appendix A
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programs, none has established criteria for evaluating these programs. However, each state
periodically reviews operations, evaluates and purchases equipment, requests revisions to
laws, and adjusts its organization in an effort to improve enforcement.
2. Comparing truck population with the number of vehicles being weighed is part of
determining the effectiveness of a truck weighing program. Also needed are data on the
overloaded truck routes arid volumes, types of movements (interstate or intrastate), vehicle
classifications, types of cargo, and distances traveled.
Essential to truck weight enforcement is the effective combination and deployment of the
various types of scales (permanent, portable, and semiportable). Through the use of data
collected in truck traffic studies, permanent scales cart be located where there are many
overloaded trucks, and these scales can be supported by roving portable-scale crews. Greater
use of the sem~portable scales should be carefully considered arid may eliminate the need for
a new permanent weigh station. Improved instrumentation for weigh stations and
semiportable stations is needed.
4. In most states, overweight violations are misdemeanors arid are processed through the courts.
In several states, an overweight violation is a civil offense, and penalties are collected at the
weigh site or within 1 5 days after the citation is issued unless a hearing is requested. Most
states have unloading requirements for an overload violation. Many enforcement officers
believe that the off-loading requirement is the most effective deterrent in a truck weight
enforcement program.
Some of the problems In truck weight enforcement can be attributed to insufficient personnel,
usually the result of an insufficient number of budgeted positions for proper operation of
permanent and portable scales. The hours of operation of scales are related to the available
personnel. Most permanent stations are operated continuously only on routes with large
volumes of Duck traffic.
6. Each state needs to evaluate its truck weight enforcement program, beginning with
cooperation within and among the agencies involved. The state needs to determine the most
effective enforcement procedures possible under the law in light of the existing facilities and
Appendix A
2
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available personnel and with minimal expenditures for additional facilities and equipment.
Long-range goals for changing state laws and improving site operations also are necessary,
as are methods for measuring the effectiveness of state truck weight enforcement programs.
Some of the possible methods are simple and can be implemented with little more than an
evaluation of existing data. Other methods require a different use of existing equipment,
additional equipment, or a change in operations.
A deterrent to truck weight enforcement effectiveness is that overweighing can prove to be
economically. beneficial for truckers. Paxson (3) demonstrated benefits to truckers of overweighing
by means of an incremental approach (decrease in transport cost per unit with increase in cargo
weight) and by using specific cargo movements to calculate the incentives to overweight. The fine
and penalty structures of various states were examined and were combined with the probability of
being weighed to calculate the expected value of being weighed to the trucker. The net benefit of
overweighing to the trucker was then shown by comparing the costs with the incentives. Finally,
actual permit costs were examined in relation to the cost of additional pavement damage caused by
overweight trucks. Paxson concluded that (a) economic incentives often exceed the expected costs
of overweighing to the trucker, (b) current enforcement programs in some states are not effective,
(c) fine structures should take account of both the amount of truck overweight and the number of
miles traveled, and (d) the cost of overweight permits does not reflect the additional pavement
damage caused by overweighing.
A Canadian study published by TRB (4) also addressed the economic disincentive of weight
enforcement activity. The object of this research was to assess the effectiveness of a truck weight
enforcement program. Truck weight regulations and trucking activity in the Province of New
Brunswick, Canada, were used as a case study. The methodology compared incremental revenues
that can be earned by overloading a particular truck configuration with the expected cost of getting
caught, taking into account the fine regime and the level of enforcement. The results of the research
demonstrated that fines are not structured in New Brunswick to be an effective deterrent for would-
be violators. Alternative enforcement programs were postulated and the deterrent effect was
evaluated.
One strategy to improve the effectiveness of truck weight enforcement effectiveness was
suggested in the Wisconsin study by Stein (5). This study recommended that weigh-in-motion data
Appendix A
3
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be utilized as a tool for prioritizing weight enforcement efforts. The suggested prioritization
indicated patrolling Interstates first, followed by U.S. numbered highways, then state trunk and town
roads.
Current Weigh-/n-Mofion Programs
Our survey of state enforcement agencies indicated that -- states conduct weigh-in-motion
efforts. Most states collect truck classification and weight data in conformance with the Traffic
Monitonng Guide (6).
Two example programs documented in the literature are Florida and Wisconsin.
Hazen (7) reported that Florida has 20 years of experience In running continuous weighing-
in-motion stations. Florida currently has 1 3 continuous WIM stations in operation which provides
a "wealth" of data. Research investigated optimum number of WIM sites required to address
pavement management systems requirements. WIM data was examined for also seasonal patterns
or other patterns for allocating a continuous WIM station to a pattern group. Florida found little or
no seasonal patterns. There was some indication of patterns by geographic area of the State. Daily
ESAL values are more variable than onginally thought. The Flonda study recommended one week
of data collection at stable sites, two-one weeks at moderately stable sites at semiannual intervals,
and four-one weeks at unstable sites spread over the quarters of a year.
Beginning In 1983, We Wisconsin Department of Transportation collected truck weight data
utilizing Bridge Weigh-In-Motion equipment at 21 sites distributed among 7 highway functional
classifications. A study by Stein (5) focused on data gathered between 1983 and 1986 on the Rural
Interstate and Rural Principal Arterial highway systems for the 5 Axle Combination Truck with
Trailer, the common eighteen wheeler and test data collected at Rural Interstate and Rural Principal
Artenal sites in 1987.
4
Appendix A
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General findings and recommendations of the Wisconsin study were as follows.
1. Composite data from all highway systems indicate approximately 14% of the 5 Axle
Combination Trucks with Trailer were operating with at least 1 possible weight violation and
over 6% had gross weight violations. On the Rural Interstate, 15% had possible weight
violations with individual stations ranging from 2% to 30%. On the Rural Principal Arterial
system, 17.6% had possible violations with the individual stations ranging from 16% to 20%.
2.
Forty percent of the ESALs observed on the Rural Interstate are attributable to excess axle
loadings. The range of observations at individual stations was ~ 7% to 55% excess ESALs.
On the Rural Principal Arterial, 29% were excess with a range of 17% to 38%.
The test data indicated that ~ 0% of the trucks had a possible violation while the basic data
indicated ~ 5% were possible violators on the Rural Interstate. These figures tend to confirm
the validity of the basic data with respect to the extent of possible violators.
4. Confirmation of the magnitude of excess ESALs is less conclusive. However, the excess
ESAL comparison In Illustration ~ 0 of 29% for We basic data and 14% In the test data tends
to be supportive of the legitimacy of the basic data.
5. The basic data exaggerate the magnitude of We severity of violations (ESALs) while not
significantly impacting on the data with respect to the number of probable violators.
6. Future analysis of buck weight data for highway systems within Wisconsin comparing data
collected utilizing one weighing system and one calibration method will remove considerable
ambiguity from the results and better establish the magnitude of the severity of the
overloaded truck. In the interim, the basic data should be utilized for highway design and
enforcement planning.
s
Appendix A
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Specific finding of the Wisconsin study having implications for pavement design are as
follows:
An examination of data collected utilizing Bridge Weigh-In-Motion equipment illustrated
Mat ESAL load factors based on data collected at enforcement scales were significantly
underestimated.
Load factors should be based on flexible pavement with a Structural Number of 5 and
terminal serviceability of 2.5 and rigid pavement with a thickness of 9-inches and a terminal
serviceability of 2.5.
3. Load factors should be maintained using current ESAL values attained utilizing weigh-in
motion systems.
Beneft/Need for Truck Weighing Programs
Truck weight enforcement programs are both necessary and beneficial. Specific discussed
aspects of this issue are the current truck overweight problem, economic impact of truck weight,
pavement damage, and safety effects of increased weight.
Current Truck Overweigh! Problem The most definitive study of the overweight problem was
conducted in Wisconsin (5). Its findings are as follows:
1 . Scope of overweight truck population. Composite data Tom all highway systems
indicate approximately 14% of the 5 Axle Combination Trucks win Trailer were
operating with at least ~ possible weight violation and over 6% had gross weight
violations. On the Rural Interstate, 15% had possible weight violations with
individual stations ranging from 2% to 30%. On the Rural Principal Arterial system
17.6% had possible violations with the individual stations ranging Dom 16% to 20%.
2. Magnitude of excess ESALs. Forty percent of the ESALs observed on the Rural
Interstate are attributable to excess axle loadings. The range of observations at
6
Appendix A
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~ndividu~ stations was 1 7% to 55°/O excess ESALs. On the Rural Pnncipal Artenal,
29% were excess with a range of 17% to 38%.
Economic impact of truck weight A New Jersey study (8) to estimate the total overweight truck
population suggested that total pavement damage attributable to all overweight trucks may approach
$20 million dollars per year. It was therefore concluded that a substantial increase in the revenue
generated by overweight trucks may be appropriate.
Pavement-related costs that might be affected by changes in truck weights include costs for
(a) new and reconstructed pavements; (b) resurfacing and other forms of pavement rehabilitation;
(c) routine maintenance, such as cleaning and filling cracks and patching potholes; and (d) effects
of users caused by changes in pavement condition.
For existing pavements, increases in traffic loadings would affect pavement rehabilitation
costs in two ways. First, an increase in traffic loadings would shorten the time interval to the next
resurfacing. Moving resurfacing expenditures nearer to the present would increase the real cost for
resurfacing because of the time value of money (incurring a $1,000 cost today is worse than
incurring a $1 ,000 cost one year from today, because in the latter case, the money could be invested
productively for a year). If the funds required to resurface highways sooner were not available to
highway agencies, the condition of the road when resurfacing is carried out (referred to as the
"terminal serviceability") would be reduced and, as discussed below, highway users would be
subjected to added cost and discomfort. Second, at the time resurfacing is required, higher traffic
loadings would either increase overlay thicknesses or require more frequent resurfacing in the future.
A cost-analysis methodology applied in TRB Special Report 225 (9) to estimate Me Impacts
of altetnadve Duck weight regulatory scenarios has implications for the development of Muck weight
enforcement M.O.E.s. This methodology consisted of three steps:
I. The added costs to highway agencies for new and reconstructed pavements and for
pavement rehabilitation were estimated assuming a 10 percent increase in traffic
loadings (as measured in ESAL-miles) on the nation's highways. Separate estimates
were developed for flexible and rigid pavements and for each of the seven regions
7 Appendix A
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and four highway classes (Rural Interstate, Rural Non-Interstate, Urban Interstate,
and Urban Non-Interstate) used in the productivity analysis.
2. For each truck weight regulatory scenario, the committee used the forecast of ~ 995
truck miles by region, highway system, truck type, and operating weight that was de
veloped as part of the productivity analysis to calculate the percentage change
(relative to the base case) in ESAL-miles by region, highway system, and pavement
type.
3. The percentage changes calculated in Step 2 were used to scale the estimates of cost
impacts developed in Step I; for example, a 5 percent increase in traffic loadings
would produce half the impact estimated in Step 1 for a 10 percent increase.
Pavement Damage Wheel loads of heavy Mucks contribute to various forms of pavement distress.
Of the various types of damage, fatigue (which leads to cracking) and permanent deformation
(rutting) are of great importance and are the primary focus of this study.
A previously cited NCHRP Synthesis (2) noted that without dedicated, persistent truck
weight enforcement officers, the highway system would have deteriorated long ago.
However, an opposing perspective regarding the effect of buck weight on pavement damage
was published by the New Jersey D.O.T. (8). This study was undertaken to quantify the magnitude
of the pavement damage done by overweight trucks in New Jersey. This was accomplished using
the AASHTO 18-Kip Equivalent Axle Load parameter, established engineering-economic
procedures, and data obtained from the New Jersey State Police. Questions specifically addressed
Include:
I. How much pavement damage is attributable to overweight trucks?
2. What are the costs associated with this damage?
3. Are these costs adequately covered by the revenues collected from the overweight
violators?
4. Is mandatory off-Ioading (requiring violators to immediately lighten their loads at the
ticketed location) justifiable?
8
Appendix A
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It was found that detected overweight trucks cause a relatively small shortening of pavement
life and, had overweight trucks been successfully off-loaded, a negligible savings would have result-
ed.
However, there is serious concern expressed in the New Jersey study that the number of
overweight trucks actually detected represents a small fraction of the total number of violators.
A Pennsylvania study (10) produced analytical guidelines for the posting of load limits. The
analysis evaluated a variety of loading conditions (i.e. various load magnitudes and configurations)
for different pavement thicknesses and material properties. It was found that axle configuration (i.e.,
single-, tandem-, and triple-axle assemblies) did not significantly affect pavement response, provided
that the load per tire remained the same. A performance model based on present serviceability index
was developed that related pavement performance to calculated subgrade strain. The program
generates information concerning predicted years to failure for different load limits. Results indicate
more damage responsibility for heavy loads on thin pavements than on thick pavements, as would
be expected. However, the study concludes that cost allocation based on marginal pavement damage
can be misleading if the initial cost of construction is not considered. The load-limit analysis
procedure presented in this study can be a valuable tool in the evaluation of axle load limits and axle
damage.
The most recent and comprehensive study of pavement effects of heavy-truck effects on
pavements was conducted at UMTRI by Dr. Tom Gillespie (11). Under NCHRP Project 1-25(1),
the mechanics of truck-pavement interaction were studied to identify relationships between truck
properties and damage (fatigue and rutting). Computer models of trucks were used to generate
representative wheel load histories characteristic of the different trucks and operating conditions.
Rigid and flexible pavement structural models were used to obtain pavement "influence functions,"
which characterize the pavement response to tire loads at any location on the roadway.
Fatigue damage to rigid and flexible pavements is most directly detennined by maximum
axle loads and pavement thickness. Fatigue damage varies over a range of 20: 1 with typical varia-
tions in axle loads and over the same range with typical variations in pavement thickness. Other
9
Appendix A
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vehicle properties have a smaller, but still significant, influence on fatigue. The relationships
between damage and certain truck properties of interest are as follows:
i. Axle loads - Fatigue damage is dominated by the most heavily loaded axles. The
first-order determinant of overall fatigue damage for a vehicle combination is the
sum of the Equivalent Single-Axle Loads (ESALs) for
each axle. Assuming a fourth-power damage relationship, a 22-km axle is 23 times
as damaging as a 10-km axle.
2. Tandem suspensions - Theoretically, tandem axles have the potential to be no more
damaging to roads than single axles with equivalent load per axle (i.e., a 36-km
tandem can be no more damaging than two 18-km singles). In practice, certain
deficiencies in the performance of tandem suspensions preclude these benefits:
a. Inequalities in static load sharing cause disproportionate fatigue from the
heavily loaded axle.
b. Most tandem suspensions produce dynamic loads comparable to their single
axle equivalents.
3. Axle spacing - Aside from the suspension effects discussed above, locating axles at
a close spacing does not contribute to pavement damage. Damage on flexible
pavements is largely insensitive to axle spacing down to the limits dictated by current
tire diameters.
Pavement Cost /mp/ications of Enforcement Effectiveness
The literature review addressed the documented sensitivity of various pavement impacts
(e.g., damage, cost) to seek implications for effects of truck weight enforcement effectiveness.
The methodology applied in TRB Special Report 225 (9) examined the impact of alternative
truck weight regulation scenarios various pavement issues. Projections of heavy-truck miles by type
of truck, region of the country, highway functional class, and operating weight were developed for
Appendix A
10
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a base case and alternative truck weight regulatory scenanos, i.e., referred to herein as "truck-weight
cases". These projections were used to estimate impacts on truck costs, pavements, bridges, and
safety. The study procedure is described as follows:
"In-depth interviews with a cross section of firms selected to represent major
segments of the trucking industry were a key input to the development of forecasts for the
alternative scenarios. The analytical procedure used for the forecasting process is based on
the assumption that all carriers would shift toward use of the most economical type of
equipment, taking into account purchase price, operating costs, and He productivity improve-
ments that might be realized by each type of equipment. The procedure takes into account
all important constraints on the operation of each type of equipment, such as regional truck
size and weight limits, the mix of commodities carried and types of operations involved, the
proportion of time the equipment is weight-limited or volume-limited, and limitations of
docks or storage capacity.
Quantitative estimates of truck traffic for alternative scenarios were developed using
a base case derived from FHWA forecasts, of 1995 vehicle miles by state, vehicle configura-
tion, and highway functional class. Although the estimates are derived using forecast 1 995
traffic volumes, they actually are designed to represent the steady-state response of the
industry to any change in weight limits; that is, they represent the situation that would exist
in 1995 if the new limits had been In effect long enough for the industry to have acquired a
fleet that had been optimized for operation under the new limits. Much of the estimated
savings resulting from higher weight limits are likely to be obtained within 2 or 3 years of
any change. However, carriers operating particularly expensive equipment arid those with
operations that can benefit only marginally from the new limits could be expected to take
appreciably longer to modify their fleet to take hill advantage of the new limits."
Pavement impacts were estimated on the basis of costs for new pavements, reconstructed
pavements, and pavement rehabilitation. Pavement rehabilitation costs, accounting for the greatest
impact, were estimated using (a) projections of truck miles by vehicle type and operating weight,
(b) AASHTO load-equivalence factors (used to calculate equivalent axle loads for different vehicles
on flexible and rigid pavemerlts), (c) data on highway miles arid paved area from the FHWA
11
Appendix A
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To
: 04
o
~ log A
_ ~
log ESAL
Di stare s s f unct ion vs .
Exhibit A - 6
tr2~f ic .
Source: McGhee, 1984
Ride Qualify AASHTO (47) reports that one ofthe major accomplishments of Weir 1956
1 960 Road Test to develop a concept for evaluating the performance of a pavement. Ride quality
was used as a measure of how well pavements could serve the public. Studies made, after
completion of the Road Test, have consistently indicated that ride quality can be correlated to
pavement roughness. It has also been shown that roughness is not only a measure of user
satisfaction (or dissatisfaction), but can also be related to user costs; i.e., vehicle operating costs and
speed profiles.
The report notes that road roughness should be considered as a fundamental requirement for
a pavement management system. There are a wide range of methods of measurement to evaluate
road roughness, either subjectively (ride quality) or objectively (roughness). For state highway
administrations the use of automated measuring devices to measure and record roughness is
considered preferable to subjective ratings. Local government agencies, which do not have access
58
Appendix A
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to automated devices, have found subjective estimates of ride quality to be a useful measure of
functional performance.
Methods for measuring roughness and interpreting roughness vary and are constantly
changing as both equipment and analytical capabilities improve. Both response type roughometers,
designed to measure vertical movement between the axle and frame of a vehicle (or trailer) and
profilometers, designed to measure the longitudinal profile, have been used to evaluate roughness.
Within any particular agency, any of the response or profilometric equipment can be used.
The pros and cons of each need to be carefully considered since the reliability of the measurement
and utility of the data (correlation to ride quality) will vary.
For comparison between agencies, the conversion to the International Roughness Index (IRI)
could be considered as a useful means of summarizing roughness measurements (101.
Physica/ Distress AASHTO (47) reported that physical distress is a measure of the road
surface deterioration caused by traffic, environment and aging.
There are no national standards for procedures to be followed or equipment to be used for
identifying pavement distress. It is, however, acknowledged that the type and cost of maintenance,
rehabilitation and reconstruction will be significantly influenced by the type, extent and severity of
distress.
The types of distress Carl generally be categorized into three classes: fracture (cracking),
distortion (rutting, corrugations, faulting), or surface wear or deterioration (raveling, spelling).
Specific descriptions of distress related to asphaltic or Portland cement concrete pavements may vary
depending on the types of distress encountered in a particular area.
Methods for evaluating distress can vary widely, ranging from "windshield" surveys from
a moving vehicle to automated equipment designs to measure and record distress in a prescribed
way. The choice of method should be made as an integral part of the PMS development. The
primary factors to consider are: applicability, cost, productivity, quality and quantity of the
information obtained. The most important of these considerations are applicability, quality and
59 Appendix A
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quantity. For example, is there a sufficient amount of the right kind of information and does the
information represent field conditions?
Currenf/y Applied M.O.E.s
The survey of states, conducted as part of the NC~P 20-34 effort, revealed little application
of truck enforcement M.O.E.s.
Twenty-three surveys were returned from state enforcement agencies, and 36 were returned
from state highway planning agencies. Appendices B arid C, respectively, to this report provide
response summaries for the enforcement and planning questionnaires. Bold face appendix entries
on questionnaires display both the number of agency responses and the corresponding percentage
of the nationwide sample. Responses are indicated in the appendices as follows.
..}
Does your state conduct an on-going truck Weigh-In-Motion (WIM)
program?
Yes IS (36%)
No ~ (10%~"
The above example signifies that IS responding enforcement agencies (or 36.0 percent of all
· ~
sampled agencies) conduct on-going WIM truck weighing activity. The state survey queried M.O.E.
information both from state enforcement agencies and state highway planning agencies.
M.O.E.s Suggested by Stale Enforcemenf Agencies Exhibit A -6 lists state truck weight
enforcement agency responses to question numbers 6 and 7, stated as follows.
..~
a.
What measures (e.g., reduction in the number, proportion, and severity of overweight
trucks) are currently applied to evaluate truck weight enforcement effectiveness?
Please explain if not included in documentation.
7. What measures (e.g., reduction in the number, proportion, and severity of
overweight trucks) are DIanned for fixture application to evaluate Duck weight
enforcement effectiveness ? Please explain."
60
Appendix A
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Arkansas None.
Colorado Vehicle Compliance Ratios.
Georgia None.
Idaho
Illinois
Iowa
Kansas None.
Michigan None.
Montana None.
Nebraska None.
1. Severity of overloads
2. Proportion of enforcement action v. number weighed
Suggested Relevant Evidence helpful, but would likely not pass legislation.
Monthly activity reports are compared to proposed goals Weight Enforcement plan submitted
to FlIWA.
New Jersey Total overweight compliance; monthly comparison with previous year.
New York No current. Planned monthly statistics re: vehicles weighed, dangerously overloaded vehicles.
North
Carolina
Oklahoma None.
No current. Plans for: (1) severity of overweight
trucks, (2) reduction in violations.
Oregon 1. Truck Weighings, annual count
2. Statewide average weight violation trends, by roadway classification.
3. Legalizations, by type (cargo shift, off-load)
Pennsylvania Truck volume, amount overweight, trip distance.
Virginia Did not complete questionnaire, due to current transition in enforcement procedures.
Washing- Compliance ratio, severity of violation, WIM monitoring.
ton
Wyoming Routine weight monitoring
Exhibit A - 6. Candidate Truck Weight Enforcement M.O.E.s
M.O.E.s reported by State Enforcement Agencies
61
Appendix A
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Of the responding states, nine indicated some applied or planned measure(s) of truck weight
enforcement effectiveness. These are listed below.
I. Severity of violation. Four states.
2. Vehicle Compliance Ratios, i.e., the number of citations as a proportion of total number of
weighed vehicles. Three states.
3. Routine weight or WIM monitoring. Three states.
4. Reduction in violations.
5. Truck Weighings, annual count
6. Statewide average weight violation trends, by roadway classification.
7. Legalizations, by type (cargo shift, off-load)
8. Comparison of monthly activity to FHWA enforcement plan goals
9. Relevant Evidence findings
Despite the fact that an introductory letter explaining the nature of the project was sent to
state enforcement agencies, it is nevertheless obvious from the above list that certain of the
suggested candidate M.O.E.s miss the point of determining what is actually accomplished by the
enforcement effort rather than merely indicating a level of enforcement effort.
M.O.E.s Based on Paveme'2~/Bridge/Safe~ Management Systems In order to assist in the
development of candidate M.O.E.s the state survey asked the following question of state highway
planning agencies. Exhibit A - 7 lists responses from 36 states.
't7. What measures are gathered (or planned for fixture data collection) in your
state's Pavement/Br~dge Management System? If convenient, enclose appro-
priate documentation portions."
Responses shown in the exhibit contain measures shown in the literature review to be
considered as candidate M.O.E.s.
62
Appendix A
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Alabama AADT, Percent Commercial Vehicles, Truck Weight
Arkansas None at this time.
Arizona None reported
Colorado Pavement - Traffic, Rut depth, Cracking, Skid, GPR, Weight
Bndge - Traffic, NBI, Weight, PONTIS (System aid to optimization of budgets and programs)
Connect
icutt
Overload permit records anticipated in PMS
Florida Final decision on variables not determined, as yet
Georgia None yet
Illinois
Extensive list of geometric and locational data provided
Kentucky Traffic volume, classification, ESALs at 64 counting stations
Kansas
. · .
Loulslana
Pavement - Portable WIM data
Bridge- SHRP data
None provided
Iowa ESALs at 18 sites; volume, classification, speed at 24 sites; volume, speed at 43 sites.
Maryland None reported.
Michigan 90 TMG WIM and 30 SHRP sites.
M in n eso ta Volumes, ve hicl e classified lions, ESALs, ro adw ay a nd st ructure inf orma lion, co n dit lo n ra ti ngs,
etc.
Nebraska None reported.
Nevada None reported.
New
Hamosh~re
IRI for pavements; 15 WIM sites
Exhibit A- 8
Measures available from Pavement Management Systems
Reported by State Highway Agencies
63
Appendix A
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Application of FHWA's Truck Weight Study
As has been noted in this review, many states collect massive WIM data from relatively
unobtrusive WIM stations for the purpose of monitoring pavement performance. The Federal
Highway Administration has developed software and distributed it to states to the purpose of
reducing and analyzing the WIM data. Data from approximately one-half of the states is maintained
in files stored at the FHWA. Summary data obtained from this source can potential be applied to
monitor long-term truck weight enforcement effectiveness.
App/icat~on of Traffic Monitoring Guide (TMG) Variables
Cottrell (25) developed a sampling plan involving the systematic deployment of portable WIM
devices at TMG sites. Courell concluded that use of the TMG and WIM systems together provide
improved monitoring of truck weight sampling procedure using the TMG and WIM systems. Four
alternatives from the TMG that were based on differentschemes for multiple measurements at
permanent WIM sites were evaluated. A Suck weight sampling plan was developed for the preferred
alternative. Truck weight sampling sites, data collection procedures, cost and resources estimates,
data from permanent WIM sites, and data management information are included in the plan.
REFERENCES
I. General Accounting Office, "Excessive Truck Weight: An Expensive Burden We Can No Longer
Support--Questionnaire Summary." Washington, D.C. (1979)
2. Downs, Hugh G., "Criteria for Evaluation of Truck Weight Enforcement Programs. " NCHRP
Synthesis of Highway Practice 82. Transportation Research Board (1981)
I. Paxson, D.S., "Value of Overweighing to Intercity Truckers." Transportation Research Record 889
Transportation Research Board (1982)
Bisson, B.G. and Gould, D.~., "Methodology for Evaluation of Truck Weight Regulation
Enforcement Programs." Transportation Research Record 1249 Transportation Research Board
(1989)
5. Stein, Paul P., et al., "The Overweight Truck in Wisconsin: Its Impact on Highway Design,
Maintenance and Enforcement Planning." Wisconsin Department of Transportation (1988)
64 Appendix A
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Management Systems, July 1990
68
~ .
Appendix A
Representative terms from entire chapter:
weight enforcement
