Contact: Richard Gruberg, MC-RIA, (202) 366-2959
In 1999 it is estimated that 1.3 percent of drivers with commercial driver's licenses (CDL) used
controlled substances and 0.2 percent used alcohol. On the basis of these findings, the Federal
Motor Carrier Safety Administration's (FMCSA) required testing rate for CDL drivers remained
at 50 percent for controlled substances and 10 percent for alcohol for calendar year 2000.
The FMCSA requires all motor carriers operating vehicles that must be driven by someone
holding a CDL to have drug and alcohol testing programs. Such vehicles include trucks with
gross combination ratings of more than 26,000 pounds, trucks carrying specific hazardous
materials that require the vehicle to be placarded in accordance with FMCSA regulations, and
buses designed to carry 16 or more passengers, including the driver. Carriers must randomly test
a fixed percentage of their CDL drivers for both alcohol (for which 10 percent of all drivers must
be tested annually) and for a specified set of controlled substances (for which 50 percent of all
drivers must be tested annually).
In the case of alcohol, a driver is in violation of FMCSA regulations when the alcohol breath
content is 0.02 grams per 210 liters of breath -- equivalent to a blood alcohol content (BAC) of
0.02 grams per deciliter. Drivers testing at this level are not permitted to perform safety sensitive
functions for at least 24 hours. In addition, drivers who test at the 0.04 g/dl level or higher must
be evaluated by a substance abuse professional and undergo additional testing before being
allowed to return to duty. For controlled substances, drivers are tested for marijuana, cocaine,
opiates, amphetamines, and PCP. The cutoff levels for identifying the use of these drugs are
based on guidelines set by the Department of Health and Human Services.
Cutoff Levels for Identifying Drug Use Among CDL Drivers
The cutoff level for alcohol is 0.02 g/210 liters breath. (FMCSA's estimated violation rate is
based on a cutoff of 0.04 g/210 liters.) The cutoff level for marijuana is 15 nanograms per
milliliter. (One nanogram equals one billionth of a gram.) The cutoff level for cocaine is 150
ng/ml. The cutoff level for opiates (morphine, codeine) is 2000 ng/ml. The cutoff level for 6-
Acetylmorphine is 10 ng/ml. (Test for 6-AM when morphine concentration exceeds 2,000
ng/ml.) The cutoff level for Amphetamine is 500 ng/ml. The cutoff level for methamphetamine
is 500 ng/ml. (Specimen must also contain amphetamine at 200 ng/ml or higher.) The cutoff
level for phencyclidine (PCP) is 25 ng/ml.
In addition to random testing, the FMCSA's drug and alcohol testing regulations require motor
carriers to perform the following types of nonrandom testing: pre-employment testing (for
controlled substances only, and only if the driver has not recently been in a drug and alcohol
testing program); post-accident testing (if the crash involved a fatality, or if the truck driver
received a citation in a crash involving a towaway or hospital-related injury); and testing of any
driver who is suspected by a supervisor of using drugs or alcohol while at work.
Motor carriers must test 50% of all company CDL drivers per year in random controlled
substance testing. (If random testing is conducted through a consortium, the number of drivers to
be tested may be based on the total number of drivers covered by the consortium, rather than the
total number of drivers in the company.) Motor carriers must test 10% of all company CDL
drivers per year in random alcohol testing. (If random testing is conducted through a consortium,
the number of drivers to be tested may be based on the total number of drivers covered by the
consortium, rather than the total number of drivers in the company.)
Motor carriers must test all CDL drivers involved in fatal crashes in post accident testing. Motor
carriers must test CDL drivers receiving citations if the crash involves towaway or
hospital-related injury. In reasonable suspicion testing, motor carriers must test any CDL driver
suspected by his/her supervisor of using alcohol or controlled substances on the job.
Motor carriers must make their annual drug and alcohol summary data available to the FMCSA
upon request. This summary information includes the number of drivers tested and the number
who tested positive for each category. Each year the FMCSA estimates drug and alcohol usage
rates for CDL drivers, based upon a statistical sample of such summary information collected
from motor carriers (in the case of alcohol FMCSA defines the positive usage rate in terms of
testing at or above the 0.04 BAC level). Estimates from the annual survey are used to evaluate
the Agency's random testing requirements for both alcohol and controlled substances. Currently,
the FMCSA requires motor carriers to test 50 percent of their CDL drivers annually for controlled
substances and 10 percent of their CDL drivers annually for alcohol. In accordance with Federal
regulations (49 CFR part 382), these requirements are subject to change, based on the results of
the annual survey.
The FMCSA drug testing requirements for motor carriers began in 1989, when interstate motor
carriers domiciled in the United States with 50 or more CDL drivers were required to implement
controlled substance testing programs (49 CFR part 391 subpart H). Interstate carriers with fewer
than 50 CDL drivers became subject to these requirements one year later. Beginning in 1995, a
new set of requirements (49 CFR part 382) took effect in response to the passage of the Omnibus
Transportation Employee Testing Act of 1991. Part 382 expanded the scope of motor carriers
covered by federal drug testing regulations to include large intrastate carriers (50 or more CDL
drivers) by 1995 and all interstate and intrastate carriers with CDL drivers by 1996. In addition to
controlled substance testing, part 382 required the implementation of alcohol testing programs.
Beginning in 1996, all motor carriers operating in the United States (both domiciled and foreign-
based) became subject to these new regulations.
Methodology - Data Collection
Each year eligible motor carriers are selected into the survey by means of a stratified random
sample. In this approach, all eligible motor carriers are classified before sample selection into
size-class groupings (or strata), based on their number of CDL drivers. A random sample of
carriers is then selected in each size-class stratum. Stratification helps to ensure that the sample is
representative and also increases the precision of the estimates. Both random and nonrandom
summary data are collected from the motor carrier.
For this survey, six size-class strata are used: 1-19 CDL drivers, 20-49 CDL drivers, 50-99 CDL
drivers, 100-999 CDL drivers, 1,000 or more CDL drivers, and size unknown. To maximize the
precision of the survey estimates, all eligible motor carriers from the largest size-class stratum
(1,000 or more CDL drivers) are selected into the sample with certainty.
In the case of random testing, the sample can be viewed as a two-stage design in which the motor
carrier is selected in the first stage and a subsample of its CDL drivers is selected in the second.
In the case of nonrandom testing, the sample represents a single-stage design in which each
sampled motor carrier reports the results for all drivers subject to pre-employment, post-accident,
and reasonable suspicion testing.
For the 1999 survey 4,027 motor carriers were solicited. Of these carriers 1,366 provided
summary data for controlled substance random testing and 1,172 provided data for random
The positive rate for controlled substance use in 1999 is estimated to be 1.3 percent with a
standard error estimate of 0.2 percent. Based on these results, a 95 percent confidence interval on
this estimate ranges from 1.0 to 1.6 percent (0.013 1.96 0.0017). Thus, if the survey were
replicated, one would expect the estimate to fall within this range in 95 out of 100 replications.
The positive rate for alcohol use in 1999 is estimated to be 0.2 percent with a standard error
estimate of approximately 0.1 percent. These results suggest that a 95 percent confidence interval
for the positive rate for alcohol ranges roughly from 0.02 percent to 0.3 percent.
The positive rate for controlled substances in 1996 was 2.2 percent with a standard error estimate
of 0.4 percent. The positive rate for controlled substances in 1997 was 1.3 percent with a
standard error estimate of 0.2 percent. The positive rate for controlled substances in 1998 was 1.5
percent with a standard error estimate of 0.2 percent.
The positive rate for alcohol (BAC greater than or equal to 0.04 percent) in 1996 was 0.2 percent
with a standard error estimate of 0.3 percent. The positive rate for alcohol (BAC greater than or
equal to 0.04 percent) in 1997 was 0.2 percent with a standard error estimate of 0.1 percent. The
positive rate for alcohol (BAC greater than or equal to 0.04 percent) in 1998 was 0.2 percent with
a standard error estimate of 0.1 percent.
The survey results suggest that the positive rates for controlled substance use and alcohol use
have been approximately the same since 1997. (The differences in the year-to-year estimates are
not statistically significant and cannot be shown to be a product of real differences in the
population over time, rather than a product of statistical sampling error.) Furthermore, the 1999
survey estimates do not suggest that the required random testing rate for controlled substances or
alcohol should be changed. For the controlled substance random testing rate to be lowered (now
at 50 percent of CDL drivers), the controlled substance usage rate estimated from the survey must
be less than 1 percent for 2 consecutive years, in accordance with FMCSA regulations. For
random alcohol testing, the testing rate is currently at the minimum allowable by FMCSA (10
percent). In order for this rate to be raised, the alcohol usage rate from the survey must be
estimated to be more than 0.5 percent in a given survey year.
The number of tested drivers evaluated by the survey each year has been too small to produce
reliable estimates of a usage rate for many of the nonrandom testing categories, particularly for
alcohol testing. In 1999 the largest number of nonrandom tests captured by the survey was in
pre-employment controlled substance testing, for which 330,686 cases were reported. On the
basis of those cases, it is estimated that in 1999, 2.3 percent of CDL drivers undergoing
pre-employment testing tested positive for controlled substances. In 1998 and 1997 the results
- Drug and Alcohol Testing Survey (Analysis Brief), FMCSA, FMCSA No. FMCSA-MCRT-
00-013, Washington, D.C., Aug. 2000.
- Drug and Alcohol Testing Survey (Analysis Brief), Federal Highway Administration, Office
of Motor Carrier Research and Standards, FHWA No. FHWA-MCRT-98-003, Washington, D.C.,
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 CDL 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
This Analysis Brief was produced by the Analysis Division in 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.
FMCSA's Office of Data Analysis and Information Systems, Analysis Division, conducted this
analysis. Contact Richard Gruberg, (202) 366-2959.
This Analysis Brief is distributed according to a standard distribution. Direct distribution is made
to the Resource Centers and Divisions.
This Analysis Brief is available at http://ai.fmcsa.dot.gov and from the Office of Data Analysis and Information Systems, (202) 366-1861.
alcohol, CDL, controlled substance, driver, motor carrier, nonrandom testing, positive rate,
random testing, sample survey, testing rate
This Analysis Brief is disseminated under the sponsorship of the U.S. Department of
Transportation (USDOT) 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.
All FMCSA Tech and Analysis Briefs are available at http://www.fmcsa.dot.gov. Please send us your comments and suggestions about the Tech and Analysis Briefs.
U.S. Department of Transportation
Federal Motor Carrier Safety Administration
Office of Research and Technology
400 Virginia Ave SW
MC-RT, Suite 600
Washington, DC 20024
Publication No. FMCSA-MCRT-01-008