FEDERAL HIGHWAY ADMINISTRATION • OFFICE OF MOTOR CARRIER AND HIGHWAY SAFETY

FHWA Contact: Sandy Zywokarte, HMCS-20, (202) 366-2987

Qualifications of Drivers — Vision

and Diabetes

Introduction 

The Federal Highway Administration (FHWA) began the Federal Waiver Study Program

in 1992. The program was initiated as a response to ongoing assessments of existing

medical standards in the Federal Motor Carrier Safety Regulations (FMCSRs) and a

directive by several Congressional committees to the FHWA to undertake a thorough

review of its physical qualification regulations. The FHWA is authorized by statute to

establish minimum driver qualifications for those who operate commercial motor 

vehicles (CMVs) in interstate commerce. The waiver program allowed CMV operators

who did not meet current Federal standards for specified medical conditions to drive 

in interstate commerce.

The conditions originally chosen for the study were vision and hearing impairments,

diabetes, and epilepsy. Because of the decision in Advocates for Highway and Auto

Safety v. Federal Highway Administration (28 F. 3d 1288, D.C. Circuit 1994), which 

vacated the rule authorizing the waivers, the FHWA did not initiate the hearing and

epilepsy waiver study programs. Although this decision directly affected the vision

waiver program, it also had an indirect effect on the other waiver study programs

because of the similar approach used to pre-qualify drivers.

This tech brief summarizes the study final report, “Qualifications of Drivers — Vision,

Diabetes, Hearing and Epilepsy,” which is now available from the National Technical

Information Service. 

Purpose

The goal of the Federal Waiver Study Program was to determine the associated risk,

based on accident involvement, of allowing CMV operators who do not meet Federal

standards for specified medical conditions to drive interstate. The assessment was

accomplished by comparing the accident involvement rates of waivered drivers to 

drivers who did meet the current standards.

The objective of the study was to use the assessment to aid in determining if current

standards could be amended without imposing additional safety risks on the public.

Methodology

Original Study Design

The Vision Waiver Program began in July 1992, when 2,686 drivers were accepted into

the program. The Diabetes Waiver Program began in mid-1993 when 139 waivers were

issued. To be accepted into the program, drivers must have operated a CMV with a

vision deficiency or diabetic condition for the three-year period preceding the waiver

program with no suspensions or revocations of their driver’s license during this period.

Drivers were also required to see a doctor who certified that the driver was able to

operate a CMV safely, despite his medical condition.

Tech Brief

The mission of the Office of

Motor Carrier and Highway

Safety is to develop and 

promote, in coordination with

other Departmental modes,

data-driven, analysis-based,

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 Motor Carrier and

Highway Safety.

There are eight major research

and technology focus areas:

regulatory evaluation and

reform; compliance and

enforcement; driver training

and performance management; driver alertness and

fatigue; driver physical 

qualifications; car-truck 

proximity; HAZMAT safety 

and cargo tank integrity; and

crash causation and profiling.

Driver physical qualifications

concentrates on the research

of specific medical conditions

in relation to CMV driving

safety, with emphasis on 

medical standards guidelines.

Office of Motor Carrier Research

and Standards

400 Seventh Street, SW

HMCS-30; Room 3107

Washington, DC 20590
To retain their waivers, drivers had to submit 

information about driving experience, including

mileage driven and accident and citation information,

plus show evidence of continued good health. 

The original design of the study was an observational,

nonrandomized model with a prospective cohort

structure. A lawsuit, however, prevented the 

execution of the study and the program was 

converted to a monitoring program. Because

researchers encountered difficulties recruiting 

volunteers for a “control” group, the accident 

experience of the waivered drivers was compared 

to the data in the General Estimates System (GES),

which represents a national safety norm for large

trucks in the U.S.

The GES is based on a probability sample of about

45,000 police accident reports selected on an annual

basis. Since 1988, GES has oversampled accidents

involving large trucks; trucks are included in this 

sample if the vehicle is over 10,000 lbs. and at least

one passenger vehicle was towed or an involved 

person was injured.

Safety Monitoring 

Safety monitoring was designed to notify the FHWA

if a threat to public safety was occurring. The 

monitoring involved comparing the accident rates 

of the waivered drivers to the national rates derived

from the GES. The overall accident rates of the

waivered group represent the cumulative number 

of accidents for drivers still in the program at the

time of the report.

To determine if the waivered drivers in the vision 

program posed an excessive threat to public safety,

the monitoring process used the 90 percent confidence intervals associated with each cumulative 

accident rate. If the lower limit of that confidence

interval did not exceed the national accident rate,

which was treated as a constant, the drivers in that

program were not considered a threat to public 

safety. 

In determining if the waivered drivers in the 

diabetes program posed an excessive threat to public

safety, researchers decided that sampling error and

confidence intervals would play no role in the 

decision process. This was done because the small

sample of drivers who received diabetes waivers

would lead to wide confidence intervals. If the 

accident rate of the waivered group was larger than

the national rate, the FHWA was notified that there

could be a threat to public safety. Again, the national

accident rate is treated as a constant since it is 

frequently expressed as an official rate without a 

confidence interval.

AHAS Lawsuit

A lawsuit was filed by the Advocates for Highway and

Auto Safety (AHAS) challenging the Vision Waiver

Program. AHAS argued that the FHWA had not given

adequate opportunity for public comment on the

waiver program. The case was argued on November

13, 1993 and the Court’s decision was announced in

August 1994. The United States Court of Appeals for

the District of Columbia Circuit found that the FHWA

had given ample opportunity for comment and that

the comments were given due consideration. 

However, the Court did find that the adoption of the

Vision Waiver Program by the FHWA was contrary to

law. To satisfy the Motor Carrier Safety Act of 1984,

waivers must uphold the requirement that there will

“not be any diminution of safety resulting from the

waiver.” The Court found no empirical support that

the Vision Waiver Program upheld this requirement,

and vacated and remanded the rule that set up the

program.

Additional criteria were developed that the currently

waivered drivers would have to meet in order to

retain their waivers, and the FHWA promised to

improve its monitoring systems to promptly identify

substandard performers within the waivered groups.

Modified Study Design

In February and March 1995, the FHWA reissued all

waivers for both the Vision Waiver Program and the

Diabetes Waiver Program with a single expiration

date of March 31, 1996. Drivers were informed in an

accompanying letter of the new expiration date and

of changes in the monitoring system and criteria for

retaining waivers.

The most important difference resulting from the

change in the waiver program came in the area of

tracking accidents and citations. The monitoring

changes meant that all incidents not only had to be

scrutinized for timely reporting, but also evaluated

for the severity of the incident and resultant charges

against the waivered driver. A check of every driver’s

motor vehicle history was completed monthly, rather

than every 6 months, as was originally planned. 

Results

There were 2,234 drivers still participating in the

Vision Waiver Program in November 1995. From

August 1992 to November 1995, 510 accidents were

reported for these drivers. Also for this period,

waivered drivers self-reported a total of 299 million

vehicle miles traveled (VMT). This shows an accident

rate of 1.076 accidents per million VMT.
The data from the GES stated that there were an 

estimated 444,000 large truck accidents in 1994 in the

United States, and the FHWA has calculated that

large trucks had 170,415 million VMT in 1994. These

data give an accident rate of 2.605 accidents per 

million VMT. A comparison of the waiver group 

accident rate and the national accident rate is shown

in Table 1. Since the waiver rate was lower than the

national rate, it appears that the waiver group does

not present a threat to public safety. 

As of November 1995, there were 118 drivers still 

participating in the Diabetes Waiver Program. From

September 1993 to November 1995, there were 

13 accidents reported for this group. For the same

period, waivered drivers self-reported 5.63 million

miles traveled. These data give an accident rate for

waivered drivers. Table 2 compares the accident rates

for Diabetes Waiver Program drivers with the national accident rate in 1994. Again, the accident rate for

waivered drivers was less than the national accident

rate, suggesting that the waivered drivers are not a

highway safety threat.

On March 26, 1996, the FHWA published a decision 

to allow remaining participants in the Vision and

Diabetes Waiver Programs to continue to operate

CMVs in interstate commerce after the expiration of

the waiver program. All drivers in good standing in

the program were exempted from the relevant 

medical regulation (vision or diabetes) through an

amendment to the FMCSRs. The FHWA indicated its

intention to monitor driver performance through

periodic checks of driving records.

Limitations

The planned prospective study was never completed.

The only quantitative results available from this 

program were embodied in the series of monitoring

reports and a final risk analysis. The risk analysis was

performed to support the grandfathering of drivers

to permanent waiver status after the program was

closed. The generalizability of the quantitative results

is, therefore, quite limited. In the first place, it was

expected that those drivers receiving waivers would

perform well because they were screened prior to

receiving a waiver. One of the screening criteria was a

three-year safe driving record prior to entering the

program. This type of record is one of the better 

predictors of subsequent driving behavior so there

was an expectation that they would perform better

than the national rate. Moreover, interim risk analyses

Table 1. 

Comparison of accident rates of CMV drivers with vision waivers to national accident rates.

Waiver Group 90% Confidence National Accident Rate

Accident Rate Interval (No. of accidents)

(No. of accidents)

Total Accidents 1.706 (510) 1.582, 1.830 2.605 (444,000)

Accident Severity

Property Damage Only 1.284 (384) 1.177, 1.392 2.048 (349,000)

Injury Involved .408 (122) .347, .469 .534 (95,000)

Fatality Involved .013 (4) .002, .024 .026 (4,615)

* Accident rates calculated per million vehicle miles traveled.

Table 2. 

Comparison of accident rates of CMV drivers with diabetes waivers to national accident rates.

Waiver Group Accident Rate National Accident Rate 

(No. of accidents) (No. of accidents)

Total Accidents 2.309 (13) 2.605 (444,000)

Accident Severity

Property Damage Only 1.776 (10) 2.048 (349,000)

Injury Involved .533 (3) .534 (91,000)

Fatality Involved .000 (0) .026 (4,615)

* Accident rates calculated per million vehicle miles traveled.
Researcher

This study was performed by

Conwal Incorporated, 6858 Old

Dominion Drive, McLean, VA

22201. Contract No. DTFH61-92-

Z-00158.

Distribution

This Tech Brief is being distributed according to a standard

distribution. Direct distribution

is being made to the Resource

Centers and Divisions.

Availability

The study final report is 

available from the National

Technical Information Service,

Telephone: (703) 605-6000.

Order No. PB-98-142649.

Key Words

driver qualification, vision, 

diabetes, risk assessment, 

commercial motor vehicle,

interstate commerce, 

commercial drivers, monitoring

protocol, screening protocol,

Federal Motor Carrier Safety

Regulations. 

Notice

This Tech Brief is disseminated

under the sponsorship of the

Department of Transportation

in the interest of information

exchange. The Tech Brief 

provides a synopsis of the

study’s final publication. The

Tech Brief does not establish

policies or regulations, nor does

it imply FHWA endorsement of

the conclusions or recommendations. The U.S. Government

assumes no liability for its 

contents or their use.

indicated that monitoring is a powerful process for producing safe driving behavior. 

As a result, safe driving was not only expected, but was reinforced by a form of social

control. In this sense, the project was not so much a study of the behavior of the

waivered driver in general as it was a test of the feasibility of a waiver program.

Further Research 

Vision Research

Based on limitations in the study design, the FHWA determined that the safety 

performance data collected under the vision waiver study program would not be 

used as the basis for any future adjustments to the vision standard. In November 1994,

the FHWA announced its intention to initiate a separate research effort to explore 

performance-based alternatives to the current vision standard. Based on comments

received from the publication of a Federal Register Notice and a public hearing, the

FHWA decided not to proceed with its proposed plan to develop a performance-based

vision standard.

In 1997, the FHWA contracted with the Beth Israel Deaconess Medical Center in Boston,

Massachusetts, to establish a small panel of medical experts to review the current vision

requirements and make recommendations for possible amendments to the present

vision standard. The medical panel report is complete and its recommendations are

under review. 

Diabetes Research

The FHWA is conducting research to: 1) assess the level of risk associated with the 

operation of CMVs by insulin-using drivers, and 2) determine if it is practical and costeffective to have a program that allows individuals with insulin-treated diabetes 

mellitus to operate a CMV. A final report on this study will be completed by January

2000.

The agency has also convened a panel of medical experts to review the diabetes 

regulations and guidelines under Part 391 of the FMCSRs and make recommendations

for amending the current Federal diabetes standard. 

September 1999

Publication No. FHWA-MCRT-99-017