U.S. Department of Transportation printed on recycled paper

National Highway Traffic Safety Administration

Percentage of Severe ADHD Young Adults

Convicted of Moving Violations

Technology Transfer Series

Number 131 July 1996

STUDY SHOWS THAT YOUNG ADULTS DIAGNOSED WITH

SEVERE ATTENTION DEFICIT HYPERACTIVY DISORDER AS

CHILDREN HAVE MORE DRIVING RISKS

Children who show symptoms of Attention Deficit purposes of this study. Comparing severe ADHDs to all

Hyperactivity Disorder (ADHD) experience difficulties others was deemed the most stringent test of the impact

at home and at school. They typically have problems of ADHD on driving history.

with inattention, hyperactivity, and impulsivity and

these translate into behavioral and academic problems. Over the course of the ongoing study, information for

The National Highway Traffic Safety Administration each child included measures of behavior and

(NHTSA) sponsored a study to assess whether ADHD temperament; problem solving styles; achievement in

diagnosed during childhood would be a risk factor for school; perceptual, social, and intellectual

poorer driving performance during early adulthood. development; and details about what was happening at

Dr. Nadine Lambert at the University of California in records obtained from the California Division of Motor

Berkeley conducted the study using a longitudinal Vehicles were added to the database for most of the

database she started in 1974 to explore the now young adults.

identification, treatment, and life histories of hyperactive

children. The database contains extensive information Complete, updated, driving records were available for

on 492 ADHD and comparably aged children selected 113 severe ADHD young adults from the time they

in 1974 from over 5,000 children in the school age obtained their first license through age 25. These

population of Alameda and Contra Costa counties in records were compared with the driving records for 335

California. comparison young adults.

The study continues to follow these 492 children into

young adulthood. In the database, 175 were diagnosed

in childhood as hyperactive, 107 showed behavioral

characteristics comparable to diagnosed ADHD subjects

but had different medical interventions and treatment

histories, and 51 had behavior problems in childhood

but without showing the symptoms of ADHD. The

remaining 159 formed a comparison group who attended

the same schools and classrooms as the ADHD subjects.

As with other disorders, ADHD symptoms span a

continuum of severity. Those who were classified for

these analyses as having severe ADHD met scoring

criteria on either the Inattention or the HyperactivityImpulsivity scales, or on both. They also demonstrated

pervasive symptoms based on both parent and teacher

ratings. Those who had more moderate and situational

symptoms as children, along with those not classified as

ADHD, composed the comparison group for the

both home and school. In the early 1990s, driving
Young adults who had been diagnosed as severe ADHD differences were not statistically significant. Among

as children were more likely than the comparison group both groups, there were only two recorded crashes that

to have been convicted of certain moving violations. involved fatalities. Both of these crashes occurred

The chart shows the percentages of both groups for the among the severe ADHDs.

violations that were statistically significant. 

While not statistically significant, as a group, the severe different between the two groups. Severe ADHD

ADHD young adults had more convictions for violations young adults, however, were more likely to have had

on every other category of moving violation than the their license suspended (45 vs 27 percent) and were

comparison group. These included reckless driving, more likely to have been fined (54 vs. 40 percent).

drunk driving, and lane placement, among other Both of these differences were statistically significant.

violations.

For non-moving violations, the severe ADHDs also had driving experience, sanctions received, and stimulant

more convictions in almost all categories. The nature of treatment histories. The study shows that attention

some of these offenses suggest that ADHD youth deficit hyperactivity disorder (ADHD) is a risk factor

compound problems when they are charged with for poorer driving performance during early adulthood.

moving violations because they are less likely to follow Youth who displayed severe symptoms of ADHD as

through the required process. Statistically significant children were more likely than a comparison group to

differences were found between the groups for 5 of the have been convicted of assorted moving and non6 non-moving violations -- equipment, licensing, failure moving violations.

to appear in court, failure to pay fines, and ignoring

police authority. There were no examples of not Limited copies of the report, prepared by Dr. Lambert,

obeying restrictions for the ADHD group.

The severe ADHDs also had slightly higher percentages

of crash involvement, but these

Punishments and sanctions were not particularly

The report summarizes additional analyses on years of

are available. To obtain a copy of Analysis of Driving

Histories of ADHD Subjects, (11 pages plus

appendices), write to the Office of Program

Development and Evaluation, NHTSA, NTS-30, 400

Seventh Street, S.W., Washington, DC 20590, or send

a fax to (202) 366-7096. Alan Block was the technical

manager of this project

.

U.S. Department 

of Transportation

National Highway 

Traffic Safety 

Administration

400 Seventh Street, S.W. NTS-33

Washington, DC 20590

TRAFFIC TECH is a publication to disseminate 

information about traffic safety programs, 

including evaluations, innovative programs, 

and new publications. Feel free to copy it as you wish. 

If you would like to receive a copy contact:

Linda Cosgrove, Ph.D., Editor, Evaluation Staff

Traffic Safety Programs

(202) 366-2759, fax (202) 366-7096

E-MAIL: lcosgrove@nhtsa.dot.gov