FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION

FMCSA Contact: Richard Gruberg, MC-RIA-20, (202) 366-2959

Motor Carrier Drug and Alcohol

Violations: Comparison of

Compliance Review Data from

SafeStat Selected Carriers and a

Random Sample of Carriers

Introduction

As of January 1, 1996, all domestic motor carriers with active commercial driver’s

license (CDL) operators must have a controlled substance and alcohol testing 

program. Foreign-based carriers with operations in the United States are also

required to have similar programs (see Part 382.115 of the Federal Motor Carrier

Safety Regulations [FMCSRs]). Noncompliance with specific requirements of Part 382

of the FMCSRs (Controlled Substances and Alcohol Use Testing) may affect a carrier’s

compliance review (CR) safety rating. 

There has been interest, both within and outside the Federal Motor Carrier Safety

Administration (FMCSA, formerly the Office of Motor Carriers of the Federal

Highway Administration), in the extent to which motor carriers are in compliance

with Part 382, as well as the extent to which the agency’s CR selection software,

known as SafeStat (Safety Status), captures noncompliant carriers. To address this

issue, a random sample of motor carriers was selected in 1997 for special “drug and

alcohol” compliance reviews (focusing solely on compliance with Part 382). These

reviews were conducted during the latter half of 1997 and in 1998. The results from

this random sample were then compared to data collected from motor carriers

recently targeted for review by SafeStat. The methodology and results of this 

analysis are presented below.

Methodology

Eight hundred motor carriers were randomly selected from FMCSA’s Motor Carrier

Management Information System (MCMIS) Census File for “drug and alcohol”

reviews by means of a stratified random sample. With this approach, carriers in the

MCMIS sampling frame were first grouped into size classes, based on their total CDL

driver count. A systematic sample of carriers (selecting every kth unit) was then

selected in each size class stratum. The size-class definitions, as well as the number of

motor carriers selected and reviewed in each size class, are given in Table 1. The size

class labeled “Unknown No. CDL Drivers” represents carriers whose total CDL driver

count was equal to zero in the MCMIS Census File—indicating that the total is either

zero or unknown. If it was later determined that such a carrier had no CDL drivers,

the review was not conducted since Part 382 would not apply.

The discrepancy shown in the table between the number of carriers selected into 

the sample in each stratum and the number of selected carriers actually reviewed

resulted from several factors. First, a selected carrier may have had a recent review,

making it inappropriate to conduct another one during this time period. Second, in

The goal of the Federal Motor

Carrier Safety Administration

(FMCSA) is to reduce the 

number and severity of large

truck-involved crashes through

more commercial motor vehicle and operator inspections

and compliance reviews,

stronger enforcement 

measures against violators,

expedited completion of 

rulemaking proceedings, 

scientifically sound research,

and effective commercial 

driver’s license testing, recordkeeping, and sanctions. 

The Office of Data Analysis

and Information Systems

develops and maintains 

systems for collecting and 

analyzing motor carrier data,

and disseminates information

on the motor carrier industry. 

This Analysis Brief has been

produced by the Analysis

Division within the FMCSA’s

Office of Data Analysis and

Information Systems. The

Division analyzes motor carrier

data pertaining to crashes,

inspections, compliance

reviews, and drug and alcohol

testing; and supports research

on the effectiveness of FMCSA

inspections and compliance

review programs. 

Office of Research and

Technology

400 Seventh Street, SW

MC-RT; Room 3107

Washington, DC 20590

Analysis Brief
the case of carriers in the “Unknown” size class, a

selected carrier may have been found to have no CDL

drivers, making it exempt from Part 382. Finally, the

total number of carriers actually reviewed depended

on the resources available in each FMCSA Service

Center for conducting such reviews.

Data on motor carrier compliance with Part 382 from

the 345 carriers in the random sample were compared

with similar data collected from motor carriers 

selected for compliance reviews by SafeStat. For the

SafeStat comparison group, only carriers reviewed in

1998 and having known CDL counts in MCMIS were

considered. (Had the carriers with “Unknown” CDL

counts been included in this group, it would have

been impossible to distinguish between those carriers

with no Part 382 violations because they have no 

CDL drivers, and those carriers with no Part 382 

violations because they are in full compliance, since

CDL driver counts are not currently a data element 

in MCMIS’s compliance review data base; for the 

random sample, such carriers did not have to be

excluded since reviews were performed only when

carriers had CDL drivers.) 

Findings

The percentage of carriers reviewed in

the random sample with at least one

acute violation, at least one critical 

violation, and any violation of Part 382

is given below in Table 2, broken down

by carrier size. The table indicates 

that those carriers whose CDL driver

information was missing in MCMIS 

(size class unknown) had the highest

rates of noncompliance with Part 382

(62 percent), followed by the “1–19 

CDL Driver” size class (45 percent).

Based on the information presented in

the table, these high violation rates

may stem from the fact that many of

these carriers do not have testing 

programs in place. Not having a testing

program in place is an acute violation

of Part 382, and may also explain why

a large percentage of the carriers in

these two class sizes have at least one

acute violation (48 percent and 40 

percent respectively).

The percentages given in Table 2 for

each size-class stratum can be used to

produce population estimates for the

percentage of carriers in the industry,

as a whole, that are in noncompliance

with Part 382. Population estimates 

for the four violation categories shown

in the table were generated using the

standard statistical formula for estimating a population percentage P from a stratified random sample:

(1) P = (1/N) * ∑Nh * ph,

where ph is the estimate of the percentage of carriers

in stratum h having the characteristic in question, Nh

is the total number of carriers in stratum h, N is the

total number of carriers in the population, and the

summation is across all strata. Formula #1 represents

a weighted average of the size-class percentage 

estimates, where each size-class estimate is weighted

according to its population size (see Table 1).

The statistical precision of P is measured by its 

variance, V:

(2) V = [1 / N2] * ∑Nh

2 * (Nh - nh) * 

{ph * (1 - ph) /nh} / (Nh - 1) ,

where nh is the number of units sampled in stratum

h. Based on the variance, V, a 95 percent confidence

interval can be developed for each population 

estimate. Based on statistical theory, one would

Table 1. 

Number of Carriers Selected into CR Random Sample 

By Size-Class Stratum

Size Class of Number in Number Number of Selected

CDL Drivers Population Selected Receiving CR 

Unknown 290,406 310 81

1–19 78,798 210 86 

20–49 4,165 70 46 

50–99 1,496 70 45 

100–999 1,399 70 45 

1000+ 102 70 42

Total 376,366 800 345 

Table 2. 

Percentage of Carriers in Random Sample in Noncompliance

with Part 382 by Size Class and Violation Type

Size Class of At Least At Least No At Least

CDL Drivers One Acute One Critical Program One

(from MCMIS) Violation Violation in Place Violation

Unknown 48% 16% 35% 62% 

1–19 40% 10% 24% 45% 

20–49 9% 33% 2% 39% 

50–99 4% 18% 0% 18% 

100–999 9% 13% 2% 16% 

1000+ 5% 17% 0% 19%
expect the population estimate to fall

within the confidence interval 95 

percent of the time, if the survey were

to be replicated multiple times. 

Population estimates and their 

associated confidence intervals are 

presented below in Table 3 for the

four violation categories.

Because the motor carriers in the

“unknown CDL” size class constitute

such a large fraction of the total motor

carrier population (77 percent), it is

not surprising that the estimates given

above are primarily driven by the data

collected from this size class (this can

be seen directly by comparing Table 3

with the results obtained for the

“unknown CDL” size class in Table 2).

If the “Unknown Number of CDL Drivers” size-class

stratum is excluded from the analysis, similar noncompliance rates can be made for the segment of 

the motor carrier population whose CDL driver 

information is known in MCMIS. This information is

given in Table 4. In this case, the estimates are primarily driven by the data collected from the “1 to 19”

size class, which constitutes 92 percent of this subpopulation. Limiting the scope of the estimates to

this subpopulation allows for a direct comparison

between the overall random sample estimates and

the overall estimates from the SafeStat comparison

group.

SafeStat Comparison Group

The percentage of motor carriers from the SafeStat

comparison group in noncompliance with Part 382 is

given in Table 5.

Comparing Table 5 with Table 2, one notes that the

random sample found a slightly higher percentage 

of noncompliant carriers in the smaller size classes,

whereas the SafeStat comparison group has a 

considerably higher percentage of such carriers in the

larger size classes. The largest discrepancy occurs in

the “1–19” size class, where the random sample

found considerably more carriers with no drug testing 

program in place (24 percent vs. 13 percent). This

result, however, may be due to the fact that the 

companies reviewed in this size class tended to be

somewhat smaller in the case of the random sample:

the average number of drivers for these carriers was

3.9 for the random sample, compared to 8.1 for the

SafeStat comparison group. Smaller companies with

minimal management structure (particularly owner

operators) may be more likely than larger companies

to have no drug testing program in place. 

Overall, 37 percent of the carriers reviewed in the

SafeStat comparison group had at least one Part 382

violation. This compares to a population estimate of

58 percent for all motor carriers, based on the 

Table 3. 

Population Estimates of the Percentage of Carriers in 

Noncompliance with Part 382, by Type of Violation, Based

on the Random Sample

At Least One At Least One No Program At Least One

Acute Violation Critical Violation in Place Violation 

46% ± 9% 15% ± 6% 32% ± 8% 58% ± 8%

Table 4. 

Population Estimates of the Percentage of Carriers in

Noncompliance with Part 382, for Carriers with Known 

CDL Counts in MCMIS, by Type of Violation, Based on

Random Sample

At Least One At Least One No Program At Least One

Acute Violation Critical Violation in Place Violation 

37% ± 9% 12% ± 6% 23% ± 8% 44% ± 10%

Table 5. 

Percentage of Carriers in in SafeStat Comparison Group in Noncompliance with Part 382 by 

Size Class and Violation Type

Size Class of No. At Least One At Least One No Program At Least One

CDL Drivers Reviews Acute Violation Critical Violation in Place Violation

1–19 2,600 24% 22% 13% 40% 

20–49 594 7% 26% 2% 29% 

50–99 218 9% 24% 1% 28% 

100–999 189 5% 22% 0% 24% 

1000+ 5 0% 20% 0% 20% 

All Carriers 3,606 20% 22% 10% 37%
Researcher

This analysis was performed

internally by FMCSA’s Office of

Data Analysis and Information

Systems, Analysis Division, 

MC-RIA, Contact: Richard

Gruberg, (202) 366-2959.

Distribution

This Analysis Brief is being 

distributed according to a 

standard distribution. Direct 

distribution is being made to

the Resource Centers and

Divisions.

Availability

This Analysis Brief is available

from the Office of Data Analysis

and Information Systems,

Telephone: (202) 366-1861.

Key Words

motor carriers, CDL drivers, 

controlled substance and 

alcohol testing programs, 

random sample survey, 

compliance review, acute 

violations, critical violations.

Notice

This Analysis Brief is disseminated under the sponsorship of the

Department of Transportation

in the interest of information

exchange. The Analysis Brief

does not establish policies or

regulations, nor does it imply

USDOT endorsement of the

conclusions or recommendations. The U.S. Government

assumes no liability for its 

contents or their use.

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random sample (Table 3), and a population estimate of 44 percent for all motor 

carriers with nonzero CDL counts in the MCMIS file (Table 4). Since the 37 percent 

noncompliance rate for the SafeStat comparison group falls within the 34 to 54 percent

confidence interval obtained from the random sample for the nonzero CDL population,

this 7 percent difference between the results from the random survey and SafeStat 

cannot be shown to be statistically significant (i.e., from the limited data, the 

difference cannot be shown to be real, even if it is). 

Since small carriers constitute a large fraction of the motor carrier population (and

hence are weighted heavily by formula #1, above) and also have the highest 

noncompliance rates for Part 382, one would expect the population estimates of 

noncompliance based on the random sample to be higher than similar rates obtained

from SafeStat. In fact, it is quite likely that in order to achieve anything close to a 44

percent noncompliance rate with carriers targeted by SafeStat, at least 90 percent of

them would have to be conducted in the “1–19” size class.

Summary

Data on motor carrier compliance with Part 382 were collected from a stratified random sample of 345 carriers and compared with data collected from carriers targeted

for review by SafeStat. Based on the stratified random sample, an estimated 32 percent

of all motor carriers do not have a drug and alcohol testing program in place and 58

percent of all motor carriers are in violation of some aspect of Part 382. If the target

population is limited to only those carriers with known CDL counts in MCMIS, the 

estimates become 23 and 44 percent, respectively. These estimates are “driven” by data

from small carriers (19 or fewer CDL drivers), which dominate the industry. Owing to

the limited sample size (345 carriers) used in this study, the confidence intervals around

these estimates are rather wide, ranging between plus or minus 8 percent to plus or

minus 10 percent. 

In the SafeStat comparison group, 10 percent of all carriers had no drug and alcohol

testing program in place and 37 percent of all carriers were in violation of at least

some aspect of Part 382. The difference between this latter noncompliance rate of 37

percent and the 44 percent noncompliance rate from the random sample (for carriers

with known CDL counts) cannot be shown to be statistically significant, given the 

limited size of the random sample.

Comparing results at the size-class level, one notes that the random sample has higher

noncompliance rates in the smaller size classes, but that the SafeStat comparison has

higher noncompliance rates in the larger size classes (50 or more drivers). The higher

rates of noncompliance in the smaller size classes for the random sample may stem in

part from the fact that motor carriers in the “1 to 19” size class tended to be smaller 

in the random sample than those selected by SafeStat.

October 2000

Publication No. FMCSA-MCRT-01-001 

Federal Motor Carrier Safety

Administration