REPORT ON THE SCOPE AND 

METHODOLOGY OF FMCSA’S REVIEW OF 

CANADIAN/MEXICAN COMPLIANCE WITH 

FEDERAL COMMERCIAL MOTOR VEHICLE 

SAFETY STANDARDS 

Federal Motor Carrier Safety Administration 

Report Number: MH-2008-081 

Date Issued: September 24, 2008 
U.S. Department of 

Memorandum

Transportation 

Office of the Secretary 

of Transportation 

Office of Inspector General 

Subject: ACTION: Report on the Scope and Methodology 

Used in FMCSA’s Review of Canadian/Mexican 

Compliance With Federal Commercial Motor 

Vehicle Safety Standards 

Report Number MH-2008-081 

Date: September 24, 2008 

From: Joseph W. Comé 

Assistant Inspector General 

for Highway and Transit Audits 

Reply to 

Attn. of: JA-40 

To: Federal Motor Carrier Safety Administrator 

This report presents the results of our audit of the Federal Motor Carrier Safety 

Administration’s (FMCSA) review of whether Canadian and Mexican commercial 

motor vehicles operating in the United States comply with National Highway 

Traffic Safety Administration (NHTSA) Federal Motor Vehicle Safety Standards 

(FMVSS).1

Section 4139(b) of the Safe, Accountable, Flexible, Efficient Transportation 

Equity Act: A Legacy for Users (SAFETEA-LU)2

 requires the Office of Inspector 

General (OIG) to comment on the scope and methodology FMCSA used in its 

review of Canadian and Mexican commercial vehicles’ compliance with FMVSS. 

The manufacturing standards are requirements, such as installation of antilock 

brake systems, for commercial vehicles made in the United States. The 

manufacturer demonstrates compliance with the standards by affixing a 

certification label to the vehicle. 

On April 20, 2007, FMCSA provided its report to Congress entitled, “The Review 

of Canadian/Mexican Commercial Vehicle Compliance with FMVSS.” FMCSA’s 

report was based on the April 30, 2006, review performed under a grant issued to 

the Texas Transportation Institute (TTI), Texas A&M University System. In that 

report, TTI estimated that over 90 percent of Mexican-owned commercial trucks, 

 

1

 FMVSS contain minimum U.S. manufacturing safety performance requirements for motor vehicles and equipment to 

protect the public against unreasonable risk of crashes due to design, construction, or performance, and protect 

against death or injury if a crash occurs. 2

 Pub. L. No. 109-59 (2005). 
2

trailers, and passenger buses entering into the United States at U.S.-Mexico 

commercial border crossings complied with FMVSS. This estimate was based on 

the examination of 3,294 vehicles at selected border crossings between 

February 13, 2006, and March 24, 2006; where all but 160 trucks, 233 trailers, and 

8 buses were determined to comply with FMVSS.3

 According to TTI, its sample 

and the probability formulas used to make estimates based on sample results 

provide valid statistical estimates at the 95-percent confidence level.4

Our audit objective was to provide our observations of the scope and methodology 

FMCSA used in its review. We conducted this audit from December 2007 

through June 2008 in accordance with Generally Accepted Government Auditing 

Standards as prescribed by the Comptroller General of the United States. We 

performed such tests as considered necessary to detect fraud, waste, and abuse. 

Exhibit A provides details of our audit scope and methodology. 

RESULTS IN BRIEF 

While FMCSA’s report provided evidence that most vehicles TTI sampled on 

behalf of FMCSA complied with FMVSS, the estimates it subsequently 

formulated based on the TTI sample were not statistically valid because of how 

the sample was selected and projected. For example: 

• Neither the border crossings nor the vehicles sampled were chosen at 

random; and therefore, the results are biased. In our opinion, random 

sampling was needed to ensure crossings and vehicles had a known chance 

of being selected, a prerequisite needed to use probability based formulas to 

make statistical projections. TTI agreed that the sample was potentially 

compromised, but opined that it did not impact the sample results. 

• Even if the sample results were not compromised, TTI used the wrong 

probability formulas to make statistical estimates. In our opinion, based on 

the multi-stage sample design used, a more complex statistical formula is 

required—one that appropriately weighs sample results and sampling errors 

at each sample stage. TTI did not agree and opined that the formulas it 

used were appropriate for the sample designed. 

Additionally, the quantitative impacts of TTI’s key assumptions are not clearly 

presented for report users to effectively evaluate the estimates made. For example, 

TTI disclosed that it assumed trucks sampled without a FMVSS or Canadian 

Motor Vehicle Safety Standards (CMVSS) certification label affixed were 

 

3

 TTI examined 1,573 Mexican-owned trucks and tractors (herein referred to as trucks), 1,334 trailers, and 387 buses. 4

 Confidence level is the probability that an interval estimate will include the population parameter. Higher 

probability means more confidence. 
3

compliant if manufactured in Mexico on or after calendar year (CY) 1996. This 

assumption was based on FMCSA’s analysis of Mexican manufacturing practices, 

which concluded that “most” model year 1996 and later Mexican-manufactured 

commercial motor vehicles “may” meet FMVSS. The report did not clearly show 

the degree to which this date influenced the estimates made.5

To provide report users with more meaningful results in any subsequent FMVSS 

compliance reviews, the Department should ensure that valid statistical methods 

are used and the quantitative impact of key assumptions are disclosed. To 

accomplish this, members of FMCSA’s staff with expertise in statistics should 

review the methods and data used. According to FMCSA personnel, this was not 

done for this study; consequently, they relied on TTI to design and implement the 

study. 

While expert reviews are not required, Department guidelines6

 recommend this 

practice for studies or other factual information products presented to Congress. 

This practice is also recommended in the Office of Management and Budget 

(OMB) September 2006 Standards and Guidelines for Statistical Surveys issued 

shortly before FMCSA provided the TTI report to Congress. The guidelines states 

that one best practice is to have a reviewer with appropriate expertise in the 

methodology consider whether appropriate statistical methods are used. 

Additionally, the guidelines state that an agency should ensure that data limitations 

and results are presented in a manner that makes the data useful. 

According to FMCSA, the concerns raised about sampling methods may be valid 

and the estimates derived by TTI may be biased by both sampling and nonsampling errors, but FMCSA does not expect that the reported TTI findings are 

significantly affected by them. We are making two recommendations that focus 

on actions FMCSA needs to take to ensure that any future FMVSS compliance 

reviews include appropriate FMCSA review and that results are clearly presented. 

Our full recommendations are listed on page 10. 

BACKGROUND 

In March 2002, FMCSA proposed rules that would require each commercial motor 

vehicle operating in interstate commerce in the United States to display a 

certification label asserting the vehicle complied with all applicable FMVSS when 

it was built. In August 2005, FMCSA withdrew the proposed rulemaking after 

 

5

 Based on other data provided in the report, we calculated that TTI counted approximately 15 percent of the trucks it 

sampled as either compliant or non-compliant with FMVSS using the vehicle manufacturing date. 6

 According to the Department, its Information Dissemination Quality Guidelines meet the criteria contained in OMB 

Guidelines for Ensuring and Maximizing the Quality, Objectivity, Utility, and Integrity of Information Disseminated 

by Federal Agencies. 
4

determining that it could ensure Mexican motor carriers’ compliance with these 

standards while operating in the United States by enforcing established Federal 

Motor Carrier Safety Regulations (FMCSRs) and policies since many of the 

FMCSRs are cross-referenced to FMVSS. Enforcement would occur during the 

carriers’ pre-authority safety audit and during U.S.-Mexico border crossings and 

U.S. roadside vehicle inspections. Additionally, FMCSA issued an internal policy 

instructing its staff to deny, suspend, or revoke a carrier’s operating authority or 

certificate of registration for making a false certification7

 or issue appropriate 

penalties for the falsification. For Canadian-domiciled carriers, FMCSA stated 

that the compatibility of CMVSS to FMVSS was confirmed by NHTSA. 

Section 4139(b) of SAFETEA-LU required FMCSA to review the degree to which 

Canadian and Mexican commercial motor vehicles, including motor carriers of 

passengers, operating or expected to operate in the United States, comply with 

FMVSS. In response to this requirement, FMCSA engaged TTI, through a grant, 

to estimate how many Mexican-owned vehicles currently entering the United 

States comply with FMVSS.8

 Although required by SAFETEA-LU to examine 

Canadian commercial motor vehicles, the review did not examine Canadiandomiciled commercial vehicles at border crossings. The review asserted that 

Canada has a long history of FMVSS compliance and comparable U.S. safety 

standards. 

As part of the grant agreement, TTI was to estimate (1) how many vehicles have 

an FMVSS or CMVSS certification label affixed and of those without an affixed 

label, how many comply based on date and location of manufacture and (2) the 

number of vehicles that will operate beyond commercial zones9

 and will comply 

with FMVSS if restrictions are lifted. Furthermore, TTI would provide the results 

of a study regarding U.S., Canada, and Mexico commercial motor vehicle 

standards and their enforcement. Exhibit B provides a summary of TTI’s results. 

FINDINGS 

Although Most Sampled Vehicles Complied with FMVSS, the 

Statistical Estimates Made Were Not Valid 

According to TTI, its sample design and probability formulas used to make 

estimates based on sample results provided valid statistical estimates at the 

 

7

 Mexico-domiciled carriers applying to operate in the United States must certify that they are in compliance with the 

FMCSR, the Hazardous Material Regulations, and FMVSS. 8

 When the TTI study was conducted in calendar year 2006, there were over 4 million truck and nearly 300,000 bus 

crossings at U.S.-Mexico commercial border crossings. 9

 Commercial zones generally extend from 3 miles to 25 miles north of U.S.-Mexico border municipalities and 

75 miles beyond the border in the state of Arizona. 
5

95-percent confidence level. In our view, while the evidence TTI collected shows 

that most vehicles sampled complied with FMVSS, the estimates it subsequently 

formulated based on the sample are not statistically valid because of how the 

sample was selected and projected. 

TTI stated in its report that it used a statistical approach to estimate how many 

Mexican-owned vehicles currently entering the United States comply with 

FMVSS; have an FMVSS or CMVSS certification label affixed; and if no label is 

affixed, comply with FMVSS based on date and location of manufacture. Further, 

it used this approach to estimate the number of vehicles that will operate beyond 

commercial zones and comply with FMVSS if restrictions are lifted. 

TTI examined a sample of 1,57310 Mexican-owned trucks (tractors), 1,334 trailers, 

and 387 buses at the U.S.-Mexico border heading to commercial zones to 

determine whether each vehicle had a FMVSS or CMVSS certification label 

affixed to it.11 If a label was not present, TTI used the vehicle identification 

number (VIN) to provide evidence of a vehicle’s date and location of 

manufacture,12 and counted the vehicle as FMVSS compliant if it met the predetermined country manufacturing dates presented in the table that follows. 

Table: FMVSS Compliant Country Manufacture Dates

Country of 

Manufacture 

Mexican-Owned 

Commercial 

Trucks and Trailers*

Mexican-Owned 

Commercial Buses*

United States 1981 1981 

Canada 1991 1971 

Mexico** 1996 None assumed to comply 

Source: TTI 

* Assumed to be FMVSS compliant if manufactured on or after the calendar year cited. 

** The dates were applied to Mexico manufactured and non-U.S. and non-Canada 

manufactured vehicles, which included trucks manufactured in Japan; trailers 

manufactured in the United Kingdom and Taiwan; and buses manufactured in Germany, 

Sweden, and Finland.

If TTI could not determine FMVSS compliance for any vehicle through the 

vehicle’s VIN or by other means, it categorized it as “missing data” and counted it 

as non-compliant with FMVSS. Of the 160 Mexican-owned trucks and 

 

10 TTI actually examined 1,574 trucks at the southern border, but only used the results of 1,573 trucks. According to 

FMCSA, TTI excluded one truck to prevent bias in the sample results. 11 According to TTI, Mexico does not have a certification label requirement similar to that of the United States. 

Therefore, no label would be present even if the vehicle was built in the same plant with the same design 

specifications as an FMVSS compliant vehicle for sale in the United States. 12 Standard VINs comprised of 17 alphanumeric characters with the first character representing the country of 

manufacture. 
6

233 trailers TTI counted as non-compliant with FMVSS, 149 trucks and 

231 trailers were attributed to missing data. According to TTI, most “missing 

data” vehicles were attributed to non-standard VINs. For example, TTI officials 

reported that at small border crossings some VINs consisted of from seven to nine 

characters or had characters with no readily apparent relation to standard U.S. VIN 

coding. 

TTI then computed statistical projections (estimates) by applying probability 

formulas to the data obtained in its sample and Mexican-owned vehicle data 

obtained from United States and Mexico transportation agencies and from the 

Internet. For example, TTI estimated that 89.8 percent of all Mexican-owned 

commercial trucks, 82.5 percent of trailers, and 97.9 percent of buses crossing into 

the United States comply with FMVSS. TTI believes its methods provided valid 

statistical estimates at the 95-percent confidence level. 

Sample Selection Was Not Appropriate for Statistical Projections 

In our view, neither the border crossings nor the vehicles examined in the sample 

were chosen at random to produce a valid statistical estimate. Random sampling 

was needed to ensure crossings and vehicles had a known chance of being 

selected, a prerequisite needed to use probability based formulas to make a 

statistical projection. 

Specifically: 

• At the first stage of sampling, TTI stratified the 24 border crossings into 

large, mid-size, and small groups depending on the vehicle traffic 

volume. Instead of randomly selecting crossings from each of those 

groups, it subjectively selected 5 of 7 from the large group, 3 of 7 from 

the mid-size group, and 2 of 10 from the small group based on higher 

truck volume. 

• At the next stage of sampling, TTI attempted to select every “nth” 

vehicle, but the effort was interrupted when U.S. Customs and Border 

Patrol Service (CBP) personnel selected the vehicles available to data 

collectors since the collectors were not allowed into the CBP primary 

selection area at the highest volume commercial crossing, the World 

Trade Bridge in Laredo, Texas. Further, at the Bridge of the Americas 

crossing in El Paso, Texas, TTI collectors lost control of the sample by 

allowing FMCSA personnel to select vehicles and collect data. 

Selecting every “nth” vehicle without knowing the universe size and 

without a random start does not render an appropriate random sample 

because it makes it impossible to calculate the selection interval. Not 
7

having a selection interval that covers the universe means not all 

vehicles have a known chance of being selected. 

TTI agreed that the sample was potentially compromised at two border crossings 

examined, but believed that it did not impact the results because (1) similar results 

were obtained at similar size crossings and (2) FMCSA and CBP personnel would 

most likely pick the worst vehicles to examine resulting in an under-reporting of 

FMVSS compliance. Our view remains the same. TTI’s subjective sampling 

eliminated the opportunity to include many vehicles and negated the use of 

probability formulas to make statistical projections. 

Use of Probability Formula Was Not Appropriate for the Sample Design 

Even if the sample results were not compromised, the estimates made were not 

statistically valid because of the way the sample was projected. TTI employed a 

stratified multi-stage sample design by first, grouping border crossings by volume; 

second, selecting crossings within each group; and third, selecting vehicles at 

crossings to examine. It then applied a probability formula designed for a simple 

random sample to make statistical projections for each group and for the overall 

sample. 

While this sample design can produce valid statistical estimates and is in line with 

Department Information Dissemination Quality Guidelines that recommend using 

multi-stage, stratifications, and clustering designs to enhance efficiency and 

accuracy, the probability formula TTI used was not appropriate. TTI’s formula 

presented results as if a simple random sample of vehicles was taken and did not 

weigh the results each group contributed to the overall results 

TTI has disagreed with our assessment and believes that the formula used is 

appropriate for the sample design. Department guidelines recommend that 

estimates be calculated using weights based on design. In our view, the multistage stratified design TTI used calls for a more complex probability formula to 

produce statistically valid estimates. Applying a simple random formula to a 

multi-stage stratified design results in a wrong point estimate (best estimate) and 

confidence limits since it does not appropriately weigh sample results and errors at 

each sample stage. 

FMCSA Statistical Experts Did Not Review the Work Before Issuance 

of Its Report 

According to FMCSA, the concerns we raised about sampling methods used may 

be valid and the estimates derived by TTI may be biased by both sampling and 

non-sampling errors. However, even though the estimates may be biased, FMCSA 
8

stated it did not expect that TTI reported findings are significantly affected. In our 

view, TTI’s report could provide report users with more meaningful results if 

members of FMCSA staff with an expertise in statistics had reviewed TTI’s 

methods and data used. According to FMCSA officials, there is no requirement to 

do so. FMCSA stated, however, that its personnel familiar with the subject matter 

reviewed the work, and they relied on TTI based on prior work TTI performed for 

them. While expert reviews are not required, Department guidelines recommend 

actions of this nature for studies or other factual information products presented to 

Congress. 

In the future, FMCSA should ensure that an expert review is incorporated into any 

review of Canadian and Mexican compliance with FMVSS. Revised OMB 

guidelines13 issued shortly after TTI issued its report and before the Department 

provided it to Congress, also express the need for an expert review. OMB’s 

September 2006 Standards and Guidelines for Statistical Surveys state that a good 

agency practice is to review for appropriate content, subject matter, statistics, and 

methodology by selecting “...reviewers with appropriate expertise in the subject 

matter, operation, or statistical program discussed in the document.” The reviewer 

should consider the: 

• accuracy and appropriateness of assumptions and limitations, 

• appropriateness of statistical methods used and reported, and 

• accuracy of calculations and formulas. 

The Quantitative Impact of Key Assumptions Was Not Clearly 

Presented 

TTI did not clearly present the quantitative impact key assumptions had on the 

estimates being reported. We had to determine the impact of the assumptions by 

analyzing the data presented throughout the report. Such assumptions can have a 

significant impact on a study of this nature. Consequently, the quantitative impact 

on the estimates should be clearly presented in the summary of the report for the 

report user. 

For example, to determine whether a sample vehicle without an appropriate 

FMVSS or CMVSS certification label complied with FMVSS, TTI made 

assumptions about FMVSS compliance that if found to be incorrect, may impact 

its estimates. 14 Specifically, TTI did not clearly disclose that a straight average of 

 

13 70 FR 55522 (September 22, 2006). 

14 Of the 1,573 trucks TTI analyzed, 1,196 had a valid manufacturing certification label; 217 were assumed compliant 

based on date of manufacture determined by researching the truck’s VIN or other data—151 United States, 

3 Canadian, and 63 Mexican; 11 did not comply with FMVSS; and 149 were non-compliant because of missing data. 
9

approximately 15 percent of the trucks it sampled were counted as either 

compliant or not compliant with FMVSS based on the location and date 

manufactured (Mexico on or after CY 1996). However, the CY 1996 date TTI 

used to justify Mexican truck compliance with FMVSS was based on an FMCSA 

analysis of Mexican manufacturing practices that concluded “...most model year 

1996 and later CMVs [commercial motor vehicles] manufactured in Mexico may 

meet the FMVSSs.”15 The source FMCSA used in support of this conclusion 

included examples where Mexican manufactured vehicles could not have 

complied with FMVSS until after CY 1996. For instance, Mexico did not adopt 

FMVSS antilock brake system requirements until March 1, 1997. 

Consequently, the percentage estimates of trucks compliant with FMVSS could 

change if better information were available regarding compliance dates used. 

Knowledge of the impact TTI’s assumptions had on the estimates made could be 

important to report users. The following are other examples that have the potential 

to influence the estimates TTI made, but were not clearly presented in the report. 

• TTI assumed that 149 (a straight average of over 9 percent) of the 

1,573 trucks sampled that did not have FMVSS or CMVSS certification 

labels were non-compliant if a non-standard or incomplete VIN was 

recorded on the data collection sheet or other information was not 

available that would identify date and location of manufacture. Neither 

the number nor percent of non-standard VIN or any other conditions 

were clearly presented in the report. 

• According to TTI, 8 (a straight average of 2 percent) of the 387 buses 

observed were categorized as Mexican-manufactured and assumed noncompliant. TTI assumed that any bus it examined that did not have a 

manufacture FMVSS or CMVSS certification label affixed were 

Mexican-manufactured buses and therefore, were non-compliant 

because little information was available to determine compliance. The 

percent of buses assumed not to be compliant was not clearly presented. 

In response to our observations regarding its assumptions, TTI stated that its 

assumptions were disclosed in the report and were based on the best information 

available. It also stated that the assumptions had a minor affect on the estimates 

and additional work would be required outside the scope established for its review 

to provide additional verification. As for missing data, TTI stated that the missing 

data assumption was attributed to the fact that a large number of sampled vehicles 

did not have a standard VIN. 

 

15 70 FR 50273 (August 26, 2005). 
10

We agree with TTI that it did disclose these assumptions in its report and that 

additional testing may have been warranted to verify key assumptions in the 

report, such as manufacturing dates or the implication of non-standard VINs. 

However, in the examples above, such assumptions have an impact on the 

compliance results as well as their usefulness of drawing meaningful conclusions. 

In our opinion, in the future, FMCSA should clearly present the quantitative 

impact of key assumptions in the report to ensure maximum usefulness of the 

statistics produced for the report user. This is consistent with revised OMB 

guidelines, which state that an agency needs to ensure that results are presented in 

a manner that makes the data as accessible and useful as possible and that 

information is presented clearly and logically. 

RECOMMENDATIONS 

We recommend that the FMCSA Administrator: 

1. Ensure that any future reviews of Canadian and Mexican compliance with 

FMVSS use valid statistical methods by having staff with statistics expertise 

review the work throughout the process and before reports are issued. 

2. Ensure that any future reviews of Canadian and Mexican compliance with 

FMVSS clearly present in the report the quantitative impact of key 

assumptions made. 

AGENCY COMMENTS AND OFFICE OF INSPECTOR GENERAL 

RESPONSE 

We provided FMCSA a draft copy of this report on June 23, 2008. On July 28, 

2008, FMCSA provided us with suggested changes to and comments on the report. 

We incorporated FMCSA’s suggested changes and comments, as appropriate. On 

September 9, 2008, FMCSA provided its written comments on the report. In its 

comments, included as an appendix to the report, FMCSA concurred with our 

recommendations and agreed to take the following actions when it conducts any 

future reviews of Canadian and Mexican compliance with FMVSS. 

• Recommendation 1. FMCSA stated that it will ensure that staff with 

statistics expertise reviews any future study methodologies and reports. 

• Recommendation 2. FMCSA stated that it will require key assumptions to 

reflect quantitative impacts in any future reports. 
11

ACTIONS REQUIRED 

We consider FMCSA’s actions to be reasonable. We consider the 

recommendations closed as FMCSA has stated that OIG’s findings will be used to 

guide FMCSA when it conducts future border activities where the level of 

compliance with vehicle safety standards is being monitored or evaluated. 

We appreciate the courtesies and cooperation of FMCSA representatives during 

this audit. If you have any questions concerning this report, please call me at 

(202) 366-5630 or Kerry R. Barras, the Program Director, at (817) 978-3318. 

# 
12

EXHIBIT A. SCOPE AND METHODOLOGY 

On April 20, 2007, the Federal Motor Carrier Safety Administration (FMCSA) 

provided its report to Congress on “The Review of Canadian/Mexican 

Commercial Vehicle Compliance with [Federal Motor Vehicle Safety Standards] 

FMVSS.” FMCSA based its report to Congress on the April 30, 2006, review by 

the Texas Transportation Institute (TTI), Texas A&M University System. Our 

audit objective was to provide our observations on the scope and methodology 

contained in FMCSA’s review. 

We conducted this audit from December 2007 through June 2008 in accordance 

with Generally Accepted Government Auditing Standards as prescribed by the 

Comptroller General of the United States. We performed such tests as we 

considered necessary to detect fraud, waste, and abuse. 

To assess the scope and methodology of the TTI review, we determined whether 

TTI met the requirements in Section 4139 of the Safe, Accountable, Flexible, 

Efficient Transportation Equity Act: A Legacy for Users. We also assessed 

whether the report met the scope and methodologies as defined in the grant 

agreement by comparing the descriptive reported results to the grant agreement. 

Additionally, we compared the sampling design and probability formulas used to 

answer the five study questions to those designs and formulas widely accepted in 

the statistical and research profession. We followed up with FMCSA and TTI on 

areas we noted with potential impact on the validity of the statistical estimates, 

such as the subjective selection of crossings noted in our report. We assessed their 

response based on widely accepted methods and Department and Office of 

Management and Budget guidelines. Furthermore, we reviewed the impact that 

disclosed or identified limitations had on the estimates made. For example, we 

researched and reviewed the support of the key assumption made in the report that 

Mexican trucks complied with FMVSS on or after CY 1996, as contained in 

FMCSA’s August 2005 Federal Register Notice. 

Finally, we reviewed FMCSA’s oversight of the grant and whether FMCSA had 

staff members with an expertise in statistics review TTI’s work during the process 

and before the final report was issued. 

Exhibit A. Scope and Methodology 
13

EXHIBIT B. SUMMARY OF TEXAS TRANSPORTATION 

INSTITUTE REPORTED RESULTS 

On April 20, 2007, FMCSA provided to Congress its report on “The Review of 

Canadian/Mexican Commercial Vehicle Compliance with [Federal Motor Vehicle 

Safety Standards] FMVSS.” FMCSA based its report to Congress on the April 30, 

2006, review by TTI, Texas A&M University System. TTI’s responses to the 

specific FMCSA questions follow. 

1) How many Mexican-owned vehicles currently entering the United States 

from Mexico comply with FMVSS? 

• At the southern border, the report estimated that 89.8 percent of 

trucks, 82.5 percent of trailers, and 97.9 percent of buses comply 

with FMVSS at a 95-percent confidence level. 

• Excluding vehicles in the sample that were counted more than once 

as a result of multiple border crossings,16 the report estimated that 

88.9 percent of trucks, 82.7 percent of trailers, and 97.1 percent of 

buses comply with FMVSS at a 95-percent confidence level. 

• Large and mid-size border crossings combined had more truck and 

tractor compliance with FMVSS than smaller border crossings—that 

is, 95.8 percent to 74.3 percent, respectively. Similar findings were 

found for trailers, but no significant differences were found for buses 

at a 95-percent confidence level. 

2) How many of these vehicles bear a FMVSS or CMVSS certification label? 

• The report stated that 76 percent of trucks bear the label 

(75.7 percent for unique crossings), 60.8 percent of trailers 

(64.5 percent for unique crossings), and 97 percent of buses 

(96.4 percent for unique crossings) at a 95-percent confidence level. 

3) How many vehicles do not bear a FMVSS certification label, but are 

assumed to comply with FMVSS because of the vehicle’s date [of 

manufacture] and location of manufacture? 

 

16 The sample included some vehicles more than once due to vehicles making multiple border crossings. The report 

also provided estimates that excluded these multiple crossings, referred to in the report as unique crossings. 

Exhibit B. Summary of Texas Transportation Institute Reported 

Results 
14

Exhibit B. Summary of Texas Transportation Institute Reported 

Results 

 

• Of the vehicles not bearing FMVSS or CMVSS certification labels, 

the report stated that 57.6 percent of trucks and tractors (54.4 percent 

for unique crossings) and 55.4 percent of trailers (51.3 percent for 

unique crossings) were assumed to be compliant at a 95-percent 

confidence level.17 The report made no estimates for Mexicanmanufactured buses, assuming none were compliant due to a lack of 

information regarding Mexican standards. 

4) How many vehicles may enter the United States from Mexico and operate 

beyond the commercial zones (when access restrictions are lifted); and of 

those vehicles, how many will comply with FMVSS? 

• TTI estimated that 2,340 of 2,442 trucks, 1,820 of 1,905 trailers, and 

76 of 78 buses would operate beyond the commercial zone. 

• Of the total annual crossings of trucks, trailers, and buses, the report 

stated that approximately 95.6 percent of trucks and tractors, 

94.2 percent of trailers, and 97.9 percent of buses are estimated to 

comply with FMVSS at a 95-percent confidence level. 

• Based on the number of carriers that applied for operating authority 

beyond the U.S. commercial zones, the report estimated that 

95.8 percent of trucks, 95.5 percent of trailers, and 97.4 percent of 

buses are expected to comply with FMVSS at a 95-percent 

confidence level.18

5) How does the United States differ from Canada and Mexico in its 

regulation and enforcement of commercial motor vehicle standards? 

• In general, CMVSS largely are similar to and patterned after 

FMVSS. 

• A direct comparison of vehicle manufacturing standards in the 

United States and Mexico is not readily made, because Mexico has 

no certification label requirement. 

17 FMCSA’s April 20, 2007, letter to Congress inaccurately reported that 48.6 percent of truck crossings, 53.3 percent 

of trailer crossings, and 49.1 percent of unique trailer crossings were assumed compliant. 18 The percentages represent a straight average calculated by FMCSA. 
15

EXHIBIT C. MAJOR CONTRIBUTORS TO THIS REPORT 

Name Title 

Kerry R. Barras Program Director 

David Pouliott Project Manager 

Petra Swartzlander Statistician 

Gerry Sheeran Senior Auditor 

Constance Hardy Analyst 

Calvin Moore Analyst 

Anette Soto Analyst 

Harriet E. Lambert Writer-Editor 

Exhibit C. Major Contributors to This Report 
16

APPENDIX. MANAGEMENT COMMENTS 

 Memorandum 

U.S. Department 

Of Transportation 

Federal Motor Carrier 

Safety Administration 

Subject:

From: 

INFORMATION: Response to Office of 

Inspector General Audit Report

John H. Hill 

Administrator 

 Date:

Reply to 

Attn: of Jeffrey K. Miller 

MC-PRS 

 

To: Joseph W. Come 

Assistant Inspector General for 

 Highway and Transit Audits 

The Federal Motor Carrier Safety Administration (FMCSA) appreciates the opportunity to review the 

Office of Inspector General (OIG) draft report titled, “Comments on the Scope and Methodology of 

FMCSA’s Review of Canadian/Mexican Compliance with Federal Commercial Motor Vehicle 

Safety Standards.” The report reviewed by your office is intended to satisfy Section 4139(b) of 

the Safe, Accountable, Flexible, Efficient, Transportation Equity Act: A Legacy for Users 

(SAFETEA-LU), which required FMCSA to review the degree to which Canadian and Mexican 

commercial motor vehicles comply with the Federal Motor Vehicle Safety Standards (FMVSS). 

Section 4139 also required the OIG to comment on the scope and methodology of FMCSA’s 

review. The findings and recommendations in the report are constructive and beneficial to the 

Agency. 

As referenced in your draft report, on April 20, 2007, FMCSA submitted its report to Congress 

entitled, “The Review of Canadian/Mexican Commercial Vehicle Compliance with FMVSS.” 

The FMCSA report was based on the April 30, 2006, review performed under a grant issued to 

the Texas Transportation Institute (TTI). In the report, TTI estimated that over 90 percent of 

Mexican-owned commercial trucks, trailers and passenger buses entering into the United States 

(U.S.) at U.S.-Mexico commercial border crossings complied with the applicable manufacturing 

standards. 

The OIG questioned the assumptions under which the review and its corresponding analyses 

were conducted, indicating that the use of random inspections rather than TTI’s sampling 

methodology would have changed the outcome. While FMCSA appreciates the OIG’s 

perspective on the methodology used, we do not believe that the impact was statistically 

significant. However, the findings in your report will guide FMCSA when it conducts future 

border activities where the level of compliance with vehicle safety standards is being monitored 

or evaluated. 

Appendix. Management Comments 
17

Appendix. Management Comments 

2 

Responses to Specific Recommendations

Recommendation 1: Ensure that SAFETEA-LU required reviews of Canadian and Mexican 

compliance with FMVSS use valid statistical methods by having staff with statistics expertise 

review the work through out the process and before the reports are issued. 

Response: The FMCSA concurs with the OIG’s recommendation and will ensure that staff with 

statistics expertise reviews any future study methodologies and reports. 

Recommendation 2: Ensure that any future reviews of Canadian and Mexican compliance with 

the FMVSS clearly present in the report the quantitative impact of key assumptions made. 

Response: The FMCSA concurs with the OIG’s recommendation and will require key 

assumptions to reflect quantitative impacts in any future reports. 

We appreciate the work conducted by the OIG and the professionalism demonstrated by the audit 

team. If you have any questions or need additional information, please contact 

Mr. William Quade, Associate Administrator for Enforcement and Program Delivery, at 

202-366-4553. 
The following page contains the textual version of the table found in this 

document. The page was not in the original document but has been added to assist 

screen readers. 
Report on the Scope and Methodology Used in 

FMCSA’s Review of Canadian/Mexican Compliance 

With Federal Commercial Motor Vehicle Safety Standards 

Section 508 Compliant Presentation 

Table. FMVSS Compliant Country Manufacture Dates 

Mexican-Owned Commercial Trucks and Trailers assumed to be FMVSS 

compliant if manufactured in the United States on or after calendar year 1981. 

Mexican-Owned Commercial Buses assumed to be FMVSS compliant if 

manufactured in the United States on or after calendar year 1981. 

Mexican-Owned Commercial Trucks and Trailers assumed to be FMVSS 

compliant if manufactured in Canada on or after calendar year 1991. 

Mexican-Owned Commercial Buses assumed to be FMVSS compliant if 

manufactured in Canada on or after calendar year 1971. 

Mexican-Owned Commercial Trucks and Trailers assumed to be FMVSS 

compliant if manufactured in Mexico on or after calendar year 1996.* 

No Mexican-owned commercial buses were assumed to be FMVSS compliant if 

manufactured in Mexico.* 

Source: TTI 

* The dates were applied to Mexico manufactured and non-U.S. and non-Canada 

manufactured vehicles, which included trucks manufactured in Japan; trailers 

manufactured in the United Kingdom and Taiwan; and buses manufactured in 

Germany, Sweden, and Finland.