A roadside survey of long-distance truck drivers in New York State determined the prevalence of sleepiness-related driving and associated job and sleep/rest factors. 25.4% of drivers fell asleep while driving a truck in the past year; 65.7% at least occasionally drove drowsy in the past month. Job and sleep/rest factors associated with these risky behaviors included type of carrier, violating hours-of-service regulations, tight delivery schedules, irregular work/rest schedules, and driving at night. Drivers believed that requiring realistic shipping schedules, education about "dangerous" drowsiness, and advance scheduling information for drivers would be most useful in reducing drowsiness.