State officials regulate intrastate trucks. National licenses have been required since 1992 for commercial vehicle operations. This requirement is intended to reduce the number of truckers using multiple state licenses to conceal the overall total of their traffic violations. Both interstate and intrastate commercial drivers must obtain such licenses if they operate trucks with gross vehicle weight ratings of 26,001 or more pounds, if they transport 16 or more passengers, or if they transport hazardous materials requiring placarding. Driver fatigue is associated with truck crashes.
Research shows truck crash risk increases with driver hours behind the wheel.
Crash risk is also higher between midnight and 6 a.m. The long hours truck drivers work cause sleep deprivation, circadian desynchronization, and fatigue. More than 25 percent reported working 100 hours or more per week, and 19 percent admitted to falling asleep at the wheel one or more times during the preceding month. The long hours driven by many truckers can lead to the use and abuse of stimulants. Onboard computers reduce the opportunities for violating the rules because they automatically record when a truck is driven and its speed.