of advanced technologies, co-funding of research and operational projects with other
agencies, Canada, and Mexico, and increased education and technical assistance
We must continue to assist States in the use of new technologies to:
• monitor carrier, driver, and vehicle compliance with safety regulations;
• automate the safety and other compliance requirements, including advanced
wei^-in-motion technologies for weight enforcement;
• use Intelligent Vehicle-Highway Systems/Commercial Vehicle Operations tech-
nologies to pre-clear vehicles with good safety performance records;
• develop tri-national electronic information systems to exchange motor carrier
• continue to improve the effectiveness of truck safety enforcement programs.
The United States, Canada, and Mexico have established a Transportation Con-
sultative Group that is concerned with (among other things) the operational aspects
of cross-border transportation. In order to assist carriers and State officials, the
three governments have begun to exchange information on Federal and State re-
quirements for the operation of motor carrier services. In addition, a system to ex-
cnange information from commercial drivers records is already being tested.
The elimination of institutional barriers is crucial to the effective implementation
of the NAFTA's provisions. Consistent with the Administration's National Program
Review initiatives and FHWA's Safety Management Systems, we must continue to
support multi-agency operational task forces in the border States in their efforts to
f)lan and coordinate activities to maximize each program, reduce costs, and stream-
ine requirements for the motor carrier industry.
With new requirements and the opening of new trade and transportation cor-
ridors, our customers need current, accurate information on requirements, travel
and amenity information, vehicle repair facilities, and road conditions. Multilingual
informational materials, information resource centers, and training programs on
how U.S. drivers and motor carrif^ -"an comply with Mexican and Canadian laws
and regulations will be required.
Question. Do you think a study might be necessary in the future to determine the
quality and quantity of Mexir»" trucks crossing the border?
Answer. Tne best estimate on the quantity of trucks crossing the border has been
provided in the FHWA's January 11, 1994, report to Congress entitled "Assessment
of Border Crossings and Transportation Corridors for North American Trade." This
report states that more than 80 percent of the growing U.S.-Mexican and U.S.-Cana-
dian trade uses highway border crossings and includes commercial truck and pas-
senger vehicle trafiic. Projections are that trucks will carry approximately 80 per-
cent of crossborder freight.
In addition, as noted in the answer to your second question, the FHWA has
awarded a grant to the lACP, through NHTSA, to study the effectiveness of com-
mercial vehicle safety enforcement along the southern border. This study will pro-
vide information about the safety of Mexican vehicles and help determine if there
is a future need for a study on the quality of the vehicles. The lACP study will be
completed in March 1995.
Question. I note that the House Appropriations Committee also included report
language calling for a second installment of the DOT's border infrastructure study.
Specifically, you will be called upon to review the distribution of funds to border
states (report due May 1995) and priority designation for infrastructure and trans-
portation needs of the border regions in the allocation of discretionary funds and
grant awards. Do you think that enforcement assistance to states should be a prior-
ity in allocation of discretionary funds or grants?
Answer. In the 1995 Department of Transportation and Related Agencies Appro-
priations Act, Pub. L. 103-331, the Congress directed the FHWA to review its dis-
tribution of funds to border regions. The enforcement assistance requirements of
border States funded by the FHWA will be included in this review.
The outcome of that review coupled with other information should provide the
Congress with a clear picture of the sufficiency of highway and motor carrier funds
allocated by the States to communities in the vicinity of border crossings and other
ports of entry. Further, the extent to which there are unmet border-related trans-
portation needs will also emerge.
Question. Enacting a new border/international trade highway funding distribution
formula will be a top priority for me in ISTEA reauthorization. Texas estimates that
over time it will need $2 billion to implement the operational improvements and
highway expansion necessary to accommodate growing NAFTA trade. We must fund
highway infrastructure in our border states and we must make our major North-
South trade arteries corridors of sophisticated transportation technology to get goods
from all over the U.S. to the growing Mexican market. What are your views on fund-
ing border/trade infrastructure?
Answer. The Department submitted a report to Congress in Januaiy 1994 enti-
tled "Assessment of Border Crossings and Transportation Corridors for North Amer-
ican Trade." It covered a wide range of border issues, including the question of fu-
ture funding and set out some fundmg options. At this time, an mteragency working
group is also studying these questions. In addition, as mentioned in the answer to
the previous question. Congress has directed the FHWA to review its distribution
of funds to border regions. We anticipate that the results of this study will be trans-
mitted to Congress in the Spring of 1995.
Question Asked by Senator Hutchison and Answer Thereto by Mr. Parker
Question. I am aware that newly developed safety products could help eliminate
separation of unit tractor-trailer accidents. This equipment would provide early
warning to a heavy vehicle driver that a trailer is not completely coupled. Does the
National Highway TrafTic Safety Administration view this technology as helpful in
enhancing highway safety, particularly where multiple trailers are involved?
Answer. The National Highway Traffic Safety Administration (NHTSA) is aware
of commercial products that ostensibly detect tractor-trailer miscouplings and signal
the driver of this event. Sellers of these devices appear to have found a market
among carriers who believe that this problem is of" sufficient concern to warrant
equipping their vehicles with these devices to protect against such occurrences.
However, our review of accident data relevant to this issue indicates that these
events are rare. In 1990, the last year for which data of this type are available,
motor carriers operating in interstate or foreign commerce reported to the Federal
Highway Administration (FHWA) that, of the 35,885 accidents involving these vehi-
cles, 79 (0.2 percent) involved tractor/trailer unit separations, resulting in 4 fatali-
ties (0.1 percent of the total reported) and 16 injuries (0.04 percent of the total re-
ported). Therefore, the agency nas deemed it neither appropriate nor justifiable to
consider requiring all truck tractors and/or trailers to be equipped with such de-
Questions Asked by Senator Hollings and Answers Thereto by GAO
Question. Has truck safety improved or deteriorated since the increase in truck
Answer. Truck lengths have increased steadily over the years. Forty-foot trailers
were gradually replaced by 45-foot trailers, and in turn by 48-foot trailers. In 1982,
the Congress required that all states permit at least 48-foot trailers and double 28-
foot conibinations. Currently, all states permit 53-foot trailers, which are replacing
many 48s, and a number of states permit even longer trailers. At the same time,
cab lengths have increased as sleeper compartments have been added. Longer com-
bination vehicles are permitted in 14 western states and on 6 turnpikes, but expan-
sion is currently frozen by the 1991 act.
Accident rates for all vehicles have improved over the years, including the rates
for trucks. There have been several reasons for this improvement, such as comple-
tion of the interstate highway system, maturing of the driver population, and high-
way safety legislation cfirected both at vehicle characteristics and driver behavior.
It is interesting to note, however, that as trucks have become larger and more
numerous, their improved safety record has been more apparent for their drivers
than for other vehicle passengers on the road. For example, fatalities among the oc-
cupants of large trucks fell from 1,287 in 1977 to 659 in 1991. During the same pe-
riod, fatalities among occupants of other vehicles involved in large truck accidents
only decreased from 3,925 to 3,705.
Question. In testimony presented to the Committee, the General Accounting Of-
fice concluded that longer combination vehicles require well-trained drivers in order
to operate with maximum safety. Are there any studies that point to other qualifica-
tions that such drivers should have?
Answer. Our November 1993 report recommended that FHWA require LCV driv-
ers to have both appropriate driving experience and good past driving records. Both
the Western Highway Institute and the Western Association of State Highway and
Transportation OfTicials recommend these requirements, but over half of the LCV
states do not requires experience or examine driver records. Four turnpikes and one
state have minimum age requirements ranging from 23 to 26. Our March 1992 hi^-
lighted operational characteristics of LCVs that can impact on safety and that re-
quire driver skill and judgment.
FHWA is in the process of establishing minimum training requirements for LCV
drivers is also soliciting comments on potential qualification requirements. Also, the
National Highway TralTic Safety Administration and FHWA are conducting a study
of drivers, which include on-the-road testing of drivers operating twin 28-foot trail-
ers. These efforts may provide useful information on needed driver qualifications for
Questions Asked by Senator Exon and Answers Thereto by GAO
Question. In the August 1994 U.S. General Accounting Ofilce (GAO) report on
longer combination vehicles (LCVs), GAO stated that the current data regarding the
operation of LCVs, including accident reports, is incomplete and scarce, thereby pre-
venting an accurate account of how LCVs affect safety on our nation's roads. What
type of data is needed and what sources of data must be used to fill the information
Answer. To determine the accident rate for any type of vehicle, the vehicle must
be clearly identified in accident reports and there must also be reliable data avail-
able on annual miles traveled by that type of vehicle. Neither of these is currently
available for LCVs. The current reporting requirements for truck accidents do not
include information on trailer lengths and require only partial information on the
number of trailers involved. State estimates of miles traveled are made for vehicles
with difierent numbers of axles, but this does not clearly distinguish LCVs from
other types of vehicles.
There are currently a number of data sources that provide vehicle accident and
usage data. FHWA's Safetynet requires states participating in the Motor Carrier
Safety Assistance Program (MCSAP) to report truck accidents. Unfortunately, many
states are not yet reporting complete and timely information. Safetynet should even-
tually improve the reporting of triples accidents, but since trailer lengths will not
be reported, double 28s that are legal nationwide will be indistinguishable from long
FHWA's Highway Performance Monitoring System provides estimates of truck
travel by vehicle classes and road types, including the number of axles on combina-
tion vehicles. FHWA has been working to improve the quality of the data, which
has been hindered by non-uniformity in state methods for selecting road sections
and counting vehicles. FHWA's mileage figures have been consistently higher than
those of other surveys, leading to a lower computed truck accident rate.
In addition to these data sources, FHWA has undertaken a study of 100 ran-
domly-selected LCV trucking companies to try to determine their safety records. Al-
though this could provide insight into LCV safety, it would not provide ongoing
Question. How could the States and Bureau of Transportation Statistics better ob-
tain and correlate relevant LCV information?
Answer. In addition to improving data weaknesses discussed above, FHWA could
use the Safetynet truck inspection data to obtain additional information on the qual-
ity of LCV maintenance. Inspection reports list the number of trailers on inspected
vehicles, so triples and doubles can be identified. If states allowing LCVs would re-
port the trailer lengths (there are optional state fields on the reporting form), the
type of double could also be identified. Once the data were available, LCV compa-
nies with a high incidence of critical defects found during inspections could be iden-
tified. To date, FHWA has done very little analysis of its inspection data — especially
by truck configuration.
Question. Please detail for the Committee the type of models and assumptions
used by GAO to help make the determinations in the GAO August 1994 report re-
garding LCV impact on safety and road repair.
Answer. One important assumption underlying the infrastructure cost and eco-
nomic benefit figures in our analysis was that LCVs would be allowed to operated
nationally on a network of highways roughly equivalent to the interstate network.
We pointed out, however, that both costs and benefits would be considerably less
if LCVs were confined to those routes that were most suitable for them in terms
of physical adequacy and traffic density.
Many of the conclusions in our report were based on studies done for the Trans-
portation Research Board, the Federal Highway Administration (FHWA), other fed-
eral agencies, or private organizations. On some issues there was consensus, such
as the view that pavement damage from LCVs would not be greater than from other
tractor trailers, providing axle load limits and bridge formula weight limits were not
increased. On other issues, such as the safety record of LCVs or their potential ef-
fect on bridges, there was less consensus and the available studies tended to reflect
the biases of sponsoring organizations. In those situations, we consulted with ex-
perts, federal, and state officials, gathered what statistical data we could find,
critiqued the studies, and tried to identify the most reasonable results. All the stud-
ies we reviewed were cited in bibliographies in our March 1992 and August 1994
Our conclusion that LCVs would not increase pavement wear should not be con-
strued to minimize the damage that heavy trucks do to pavements. Damage to pave-
ments is measured in equivalent single axle loads — the damage done by a single
pass of an 18,000 pound axle. Damage increases geometrically as axle load in-
creases, so a heavy truck accounts for much more damage than a passenger car.
FHWA has calculated that tractor trailers account for at least 91 percent of the axle
loadings on rural interstate highways, and that axle loadings increased 350 percent
between 1970 and 1990. A particular concern are trucks that exceed legal load lim-
its and avoid detection. One state has estimated that as many as 20 percent of
trucks are operating overweight.
For the most part we did not employ models ourselves. However, to obtain esti-
mates of the potential need to replace bridges for LCV use, we requested a new
analysis from FHWA using data in the National Bridge Inventory. We consulted
with FHWA in determining the gross weight and dimensions of vehicles to be used
in the analysis, in order to reflect the practical maximums that would likely be al-
lowed when bridge formula limits were applied. These vehicles are pictured on p.
21 of our August 1994 report. FHWA's program calculated the maximum stress on
bridge members that each vehicle would create, and compared that to the load rat-
ings of bridges in the inventory. When the LCV stress calculation exceeded a
bridge's load rating, that bridge was counted as needing replacement, using cost fig-
ures reported by the states. However, if a bridge also had an inadequate rating for
currently legal trucks, that bridge was not counted as an LCV cost.
States are expected to report two load ratings for each bridge: an inventory rating
which allows 55 percent of yield stress, and an operating rating which allows 75
percent of yield stress. FHWA believed that for estimating potential bridge costs,
it was reasonable to use an intermediate rating (about 65 percent of yield stress)
and its program was designed to calculate this. We asked FHWA to estimate bridge
replacement costs using all three ratings, but FHWA found that many operating
ratings had not been correctly reported by states, and hence that part of the analy-
sis was not possible to do with any degree of reliability. FHWA provided us results
using the inventory ratings, which had also been used in a study sponsored by the
Association of American Railroads, and their own intermediate ratings. After speak-
ing with other bridge experts, we decided that it was more reasonable to base our
conclusions on FHWA's intermediate rating than on the inventory rating. However,
in our report we also mentioned the much higher cost figures that resulted when
the inventory ratings were used.
We also critiqued analyses of potential rail diversion from LCVs that had been
done using a model maintained by the Association of American Railroads. Our res-
ervations about that model were detailed in appendix I of our August 1994 report.
Questions Asked by Senator Hollings and Senator Exon and Answers
Thereto by Mr. Donaldson
Senator Hollings. The Advocates for Highway and Auto Safety contend that
longer-combination vehicles are more dangerous than single trailers, yet the U.S.
General Accounting Office's study suggests that on balance the evidence does not
support such a conclusion. Please provide the Committee with an explanation for
the discrepancy in these conclusions.
longer-combination vehicle data
Senator Exon. The U.S. General Accounting Office (GAO) has stated that avail-
able accident reports and data are insufficient to accurately characterize the correla-
tion between longer-combination vehicles (LCVs) and safety. In testimony before the
Committee, Advocates for Highway and Auto Safety (Advocates) stated that these
LCVs are not only dangerous to the travelling public, but are responsible for sub-
stantially expediting the deterioration of our nation's roads. On what statistics and
sources of information are these conclusions based?
Answer. I will address these questions as a unit and append additional informa-
tion in response to the separate issue on bridge and pavement deterioration.
The GAO's claim that LCVs are no more dangerous than other combination
trucks, particularly single semi-trailer rigs, is not based on a comprehensive consid-
eration of the relevant evidence. In fact, a review of the documentation of the three
GAO studies over the past few years that review LCV safety fail to acknowledge
numerous studies, including well-known data analyses performed by the Federal
Highway Administration and the National Highway TraHic Safety Administration.
That said, I must point out that providing the Committee with a exhaustive re-
view of all of the available evidence would be equivalent to authoring a separate
study as a response. I will, however, review with the Committee the most prominent
indicators of LCV crash overinvolvement.
First of all, it is well-known and well-documented that multi-trailer combination
trucks of all varieties are over involved in the most dangerous kinds of heavy vehi-
cle crashes — jackknifes and rollovers:
Combination Vehicle Fatalities Involving Jackknifing
Source US DOT, National Highway iratlic Safety Administration. Fatal Aaident Reporting System, 1988
All multi-trailer rigs, especially all short doubles and triples, are more prone to
jackknife and rollover because:
• Drive wheels carry a lower proportion of total load than singles, thus promoting
engine braking lock-up.
• Since multi-trailer rigs have much more opportunity to be unevenly loaded,
jackknifing is much more frequent when axles do not carry balanced loads.
• Shorter cargo units and multiple articulation points -three pivot points in tri-
ples — provide less resistance to lateral forces once wheel lockup occurs or oscillatory
steering inputs occur, thereby promoting rollover.
Combination Vehicle Fatalities Involving Rollover
Soorce U S (X)T, National Highway Traffic Safety Administration, State Accident Report Forms Catalogue, 1988
Other data analysis of twin-28-foot semi-trailer/trailer combinations alone shows
a jackknife death rate of 14.5 percent and a rollover death rate of 23.5 percent.
Among the numerous studies that have demonstrated repeatedly the crash
overinvolvement of multi-trailer combinations, Oliver Carsten of the University of
Michigan Transportation Research Institute reported at the National Truck Safety
Symposium held in Washington, D.C. on June 30, 1987, that even the data base for-
merly maintained by the Federal Highway Administration which represents carrier
voluntary crash reporting shows that all doubles have a probability of rollover four
times greater than that for single trailer rigs. See p. 1 and, e.g., Tables 2 and 3.
The GAO is correct, however, that current data collection systems are fundamen-
tally deficient in that, first and foremost, either the basic configuration type of a
combination truck is not recorded on crash report forms or, in those instances where
configuration category is solicited from attending ofiicers, the configuration is mis-
reported. (For example, in the few states where configuration type is asked on the
accident form, it is well-known that enforcement authorities will sometimes code
"triple" for a western double with two trailing units — the officer simply looks at the
choices listed on the form, looks at the crasn-involved rig, counts the tractor and
two trailers=three units=triple.)
In addition, as shown by Roger Mingo et al. in 1990, the appropriate analysis of
the Fatal Accident Report System (FARS) from the National Highway Traffic Safety
Administration, the Trucks in Fatal Accidents (TEFA) data gathered and collated by
the University of Michigan Transportation Research Institute, and the Truck Inven-
tory and Use Survey (TlUS) conducted every five years by the Federal Highway Ad-
ministration generates crash involvement figures for multi-unit rigs that closely
track the FAKS data on jackknife and rollover involvements which I have shown
Mingo, et al., found that fatal crash rates for doubles of all kinds, for example,
are 22 percent to 42 percent higher than for standard "eighteen-wheelers."^ In
breaking down data by state, California, which uses western doubles extensively,
shows that the fatal crash involvement rate in the state in the 1988 FARS is 98
percent higher than for single-trailer combinations, 115 percent higher than for sin-
gle unit trucks, and 173 percent higher than for passenger vehicles.^
In further analysis of FARS, TIFA, and TIUS data in a May 17, 1991, paper,
Mingo used an extremely conservative definition of LCVs to show that LCV crash
involvement underreporting is a pervasive problem in accident data collection and
evaluation."* From 1980 to 1987 alone, at least 71 people died in LCV crashes. Under
a less conservative, but still carefully argued, definition of what constitutes an LCV
in these data bases, at least 100 people died in LCV accidents. Both of these figures
exceed by an order of magnitude the claims of the trucking industry on the safety
record of all LCVs. In general, trucking representatives have claimed that LCVs of
all types were responsible for only a handful of deaths — perhaps nine or less — dur-
ing the entire 19808.^
Mingo's analysis relies on a categorization of TIFA data by configuration and in-