FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION

Contact: Ron Knipling, (202) 366-2981

Driver Alertness and Fatigue:

Summary of Completed Research

Projects, 1995–98

Introduction

This document describes projects in the Federal Motor Carrier Safety Administration’s

(FMCSA) Driver Alertness and Fatigue Research and Technology (R&T) focus area that

were completed during the years 1995 to 1998 under the former Office of Motor

Carriers (OMC) in the Federal Highway Administration (FHWA). Information on more

recently completed, current, and planned projects on driver fatigue is contained in the

Driver Alertness and Fatigue R&T Focus Area Summary, which is available on the

FMCSA Web site: http://www.fmcsa.dot.gov.

Driver Fatigue and Alertness Study (DFAS)

FMCSA Project Manager: Deborah Freund, (202) 366-5541

The DFAS, performed by the Essex Corporation, was the most comprehensive overthe-road study of commercial driver alertness ever conducted. It was a collaborative

effort involving FHWA OMC, Transport Canada, the Trucking Research Institute (TRI) of

the American Trucking Associations (ATA) Foundation, three motor carriers, and other

research and industry organizations.

The study involved real revenue runs, 4 different driving schedules, 80 drivers, and

more than 200,000 miles of highway driving. Numerous measures were taken of the

drivers’ alertness and performance during driving and of their physiology during 

off-duty sleep periods. The DFAS results are major scientific inputs to the current 

re-examination of FMCSA’s 60-year-old driver hours-of-service (HOS) regulations. Major

findings included: 

• Driver alertness and performance were more consistently related to time-of-day than

to time-on-task. Drowsiness episodes were eight times more likely between midnight

and 6 a.m. than during other times.

• During their daily main sleep period, drivers slept for only about 5 hours, which was

2 hours less sleep than their “ideal” requirement of slightly over 7 hours.

• Drivers’ stated self-assessments of their levels of alertness did not correlate well with

objective measures of performance. Drivers were not very good at assessing their

own levels of alertness.

• There were significant individual differences among drivers in levels of alertness and

performance. 

The DFAS Executive Summary is available on the FMCSA Web site.

Final Report: available from NTIS (PB 98-102346)

Technical Summary: available from NTIS (PB 97-129688)

Tech Brief

The mission of the Federal

Motor Carrier Safety

Administration is to develop

and promote, in coordination

with other Departmental

modes, data-driven, analysisbased, and innovative programs to achieve continuous

safety improvements in the

Nation’s highway system,

intermodal connections, and

motor carrier operations. 

The Office of Motor Carrier

Research and Standards 

manages the safety regulatory

program and the central

research management 

function for the FMCSA.

There are eight major research

and technology focus areas:

crash causation and profiling;

regulatory evaluation and

reform; compliance and

enforcement; HAZMAT safety

and cargo tank integrity; 

driver training and performance management; driver

alertness and fatigue; driver

physical qualifications; and

car-truck proximity.

Driver alertness and fatigue

primarily supports current 

and future hours-of-service

rulemaking activities, along

with fatigue outreach and

fatigue management 

technology development.

Office of Motor Carrier Research

and Standards

400 Seventh Street, SW

Room 3107

Washington, DC 20590
Fitness-for-Duty Testing

Project Manager: Kate Hartman, (202) 366-2742

This fatigue management technology involves the

administration of psychomotor tests to drivers at the

beginning of the job shift and/or during short breaks

periodically during the shift. Through the TRI,

Evaluation Systems, Inc. developed and evaluated a

fitness-for-duty testing device for commercial motor

vehicle (CMV) drivers. Thirty drivers were tested on

cognitive/psychomotor tasks on two different types of

testing platforms: in-terminal desk top computers and

truck cab mounted miniaturized computers. Data on

the drivers’ test results, acceptance of the tasks, the

effects of terminal and cab environments on the 

computer hardware, and system reliability and 

maintainability all supported the feasibility of using

short (5-10 minute) tests to identify fatigued drivers.

This study documented the concept and feasibility 

of employing in-terminal and in-vehicle testing

devices for determining the fitness of CMV drivers 

to safely operate their vehicles. Results were 

reported in a November 1994 FHWA publication,

Feasibility of Carrier-Based Fitness-for-Duty Testing 

of Commercial Drivers.

Final Report: FHWA-MC-95-011, available from NTIS 

(PB 95-226908)

CMV Rest Areas I: Making Space 

for Safety

Project Manager: Bob Davis, (202) 366-2997

This TRI study determined what public rest area and

privately owned rest stop services are needed by CMV

drivers and how well the needs were being met. The

study documented a significant shortage of rest area

parking for commercial vehicles and drivers. It also

revealed private sector efforts to expand spaces at

truck stops to meet this need. Partly in response to

the study, about half of U.S. States now permit their

CMV weigh stations to remain open as rest areas

when they are not being used as weigh stations.

The U.S. Congress added in the 1995 National

Highway System Designation Act a provision for 

100 percent Federal funding of safety rest area 

construction and modification, a measure expected to

stimulate expanded rest areas for trucks. The final

study report is Commercial Driver Rest & Parking

Requirements: Making Space for Safety. A conference

work session on CMV parking “best practices” was

held in June 1999. A TEA21-directed follow-up study

is currently underway and is being managed by Ray

Krammes of the FHWA Office of Safety Research and

Development, (202) 493-3312.

Final Report: FHWA-MC-96-0010, available from NTIS 

(PB 97-124705)

Tech Brief: FHWA-MCRT-98-002, August 1998

Multi-Trailer Combination Vehicle Stress

and Fatigue

FMCSA Project Manager: Deborah Freund, 

(202) 366-5541

FHWA and the National Highway Traffic Safety

Administration (NHTSA) co-sponsored this study, 

performed by Battelle, of the effect of multiple-trailer

combination vehicle (MTCV) operation on driver stress

and fatigue. Its goal was to determine whether there

are differences in driver alertness and performance

arising from driving single-trailer versus two different

types of triple-trailer combinations: those employing

A-dollies and those employing C-dollies. Twenty-four

experienced MTCV drivers each drove six round trips

(two with each configuration). Total mileage per 

driver was about 2,700 miles. Trailer configuration

was found to affect driver stress/fatigue as measured

by lanekeeping, driver subjective workload, and 

physiological state. Task demands were greatest with

triple/A-dollies, followed by triple/C-dollies and, last,

single-trailers. However, stress/fatigue differences

relating to trailer configuration were small compared

to the individual differences among drivers. 

Alertness correlated much more highly with driver

individual differences than with vehicle configuration.

A summary report was submitted to Congress in

March 1996.

Validation of Eye and Other

Psychophysiological Monitors

NHTSA Project Manager, Dr. Paul Rau, 

(202) 366-0418 

This Intelligent Transportation Systems/ Commercial

Vehicle Operations (ITS/CVO)-funded effort was 

managed by the NHTSA Office of Vehicle Safety

Research. Under the program, the University of

Pennsylvania (UPENN) conducted laboratory experiments to evaluate the validity, sensitivity, and 

reliability of selected personal (psychophysiological)

fatigue detection devices and measures, including 

eye closure measures such as PERCLOS, a measure of

eyelid droop identified in earlier NHTSA research 

as being a promising index of fatigue. Other 

psychophysiological measures assessed included two

eye blink measures, two electroencephalograph 

(EEG) measures, and a head movement detector. 

All measures had some validity, but the results 

corroborated most strongly the validity of PERCLOS.

FHWA and NHTSA believe that PERCLOS is the most

promising real-time measure of driver alertness for 

in-vehicle systems. For assured validity, in-vehicle

alertness monitors should measure PERCLOS, 

PERCLOS correlates (psychophysiological or 

behavioral), or should otherwise be validated in a

manner similar to this study. The final report is

Evaluation of Techniques for Ocular Measurement as

an Index of Fatigue and the Basis for Alertness

Management. Follow-up laboratory human factors
studies of the driver-vehicle interface

for PERCLOS-based in-vehicle alertness monitoring are underway.

Final Report: NHTSA DOT HS 808 762,

April 1998, available from NTIS 

(PB 99-150237)

Tech Brief: FHWA-MCRT-98-006, 

October 1998

Local/Short Haul Driver

Fatigue Crash Data Analysis

FMCSA Project Manager: Ron

Knipling, (202)366-2981

This small analytical study, 

performed by the University of

Michigan Transportation Research

Institute (UMTRI), developed several

definitions of local/short haul (LSH)

versus over-the-road trucks and

examined the prevalence of driver

fatigue as a principal factor in truck

crashes. Data sources included the

1992 Truck Inventory and Use Survey

and 1991–93 Trucks Involved in Fatal

Accidents files. LSH trucks in these

crash data files were defined based

on vehicle size (i.e., Class 3-6 singleunit straight trucks) and/or by 

operational nature (i.e., trip length).

Not surprisingly, trip distance was

found to have the most pronounced effect on the

percentage of fatal crashes that were fatigue-related;

shorter trips are associated with a much lower 

incidence. The risk of LSH truck involvement in

fatigue-related fatal crashes is a fraction of that of

over-the-road trucks. The FMCSA Project Manager for

a current, larger human factors study of LSH driver

fatigue (which has included both focus groups and

instrumented vehicle studies) is Bob Carroll, (202) 

366-9109. 

Final Report: FHWA-MC-98-016, available from NTIS 

(PB 98-127129)

Tech Brief: FHWA-MCRT-99-002, November 1998

Shipper Involvement in HOS Violations

FMCSA Project Manager: Elaine Riccio, 

(202) 366-2981

Congress directed FHWA “to determine the scope,

nature, and extent of shipper involvement in driver

noncompliance with the safety regulations.” This

study, conducted by Global Exchange, Inc., employed

focus groups to generate qualitative data about 

shipper demands on motor carriers and drivers. The

study found that pick-up and delivery demands by

shippers do lead to HOS violations, but that all

involved parties — receivers, shippers, brokers, 

schedulers, dispatchers, and drivers themselves —

contribute to the problem of HOS noncompliance.

Moreover, all of these parties have a role to play in

resolving the problem. In particular, the fleet 

dispatcher plays a crucial role in setting schedules to

balance HOS requirements and driver rest needs

against delivery requirements. The final report, A

Qualitative Assessment of the Role of Shippers and

Others in Driver Compliance with Federal Safety

Regulations has been published. The FMCSA Project

Manager for a current follow-on study on

shipper/receiver-encouraged HOS violations is Albert

Alvarez, (202) 366-4706. 

Final Report: FHWA-MC-98-049, available from NTIS 

(PB 98-172448)

Tech Brief: FHWA-MCRT-99-004, December 1998

Assessment of Electronic On-Board

Recorders for HOS Compliance

FMCSA Project Manager: Ron Knipling, 

(202) 366-2981

This project, performed by UMTRI through a contract

with the Private Fleet Management Institute of the

National Private Truck Council, assessed the costs and

benefits of the use of electronic on-board recorders

(EOBRs) for compliance with the HOS regulations.

Driver fatigue is a significant risk factor in commercial transportation,

since drivers may be on the road up to 10 hours without taking a

break, often drive at night, and have irregular and unpredictable work

schedules. Over the past decade, driver drowsiness has been the subject of intensified Department of Transportation interest and activity.

Photo courtesy of Volvo Trucks
Distribution

This Tech Brief is being distributed according to a standard

distribution. Direct distribution

is being made to the Resource

Centers and Divisions.

Availability

Several study final reports are

available from the National

Technical Information Service,

Telephone: (703) 605-6000.

More information about each

completed fatigue research 

project can be obtained from

the FMCSA project manager.

Key Words

motor carrier safety, driver

fatigue, fitness-for-duty, 

highway rest parking, multitrailer combination vehicles,

shippers, PERCLOS, vigilance

monitoring, electronic 

on-board recorders.

Notice

This Tech Brief is disseminated

under the sponsorship of the

Department of Transportation 

in the interest of information

exchange. The Tech 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.

Average EOBR acquisition and installation costs averaged approximately $2,000 per

vehicle; annual operating and maintenance costs were about $200 per vehicle. The use

and benefits of EOBRs vary widely for different segments of the motor carrier industry;

almost all current use is by private fleets. The benefits associated with electronic HOS

recording lie largely in the time savings for drivers in maintaining HOS logs. These 

savings averaged about 20 minutes per driver per day. Also, managers of fleets using

EOBRs saved an additional 20 minutes per driver per month in management review

and administration time. A planned FY’00-02 program, Technology Deployment for

Improved HOS Compliance, will address EOBRs and related technologies for improving

HOS compliance and driver fatigue management.

Final Report: FHWA-MC-99-059, available from NTIS (PB 99-111866)

Tech Brief: FHWA-MCRT-99-007, February 1999

Conference on Driver Vigilance Monitoring

In December 1996, OMC and TRI jointly sponsored a conference on technological

approaches to counteracting fatigue, with emphasis on in-vehicle monitoring of driver

alertness and actigraphic monitoring of driver sleep. Topics addressed included 

research findings on driver alertness, updates on technology, and strategies for future

deployment. 

Conference on Managing Fatigue In Transportation

In April 1997, this international, multi-modal conference, jointly sponsored by FHWA,

ATA, NHTSA, the Association of American Railroads, the Federal Railroad

Administration, and the National Transportation Safety Board, addressed ways to

improve transportation operator alertness and lower crash risk. Expert speakers

addressed a variety of topics related to the improvement of operator fatigue management, including improving sleep, monitoring operator alertness, alternative approaches

to hours-of-service (HOS) regulation, and new methods and technologies in fatigue

management. Conference proceedings are available from Government Institutes, Inc.:

(301) 921-2355.

Conference on Rest Area Parking

In June 1999, FHWA conducted a forum to address CMV rest area availability and 

safety needs; participants included state enforcement and highway officials, safety

advocates and research organizations, and industry associations. The conference 

identified, considered, and promoted best practices developed by public and private

sector organizations and jurisdictions to expand the number of available parking

spaces for CMV drivers needing rest. Conference proceedings are available from Ray

Krammes, (202) 493-3312.

Further Information

Internet users may access further information on the FMCSA driver fatigue R&T 

programs through their Web site: http://www.fmcsa.dot.gov. The FMCSA is interested 

in receiving information about new driver fatigue research. E-mail Ron Knipling at

ron.knipling@fhwa.dot.gov or fax (202) 366-8842. 

DOT-wide activities related to transportation operator fatigue are described in the

DOT’s Fatigue Resource Directory at: http://www.hf.faa.gov/dot/fatigue/.

January 2000

Publication No. FMCSA-MCRT-00-006