Some commercial truck drivers choose to violate commercial trucking regulations by speeding, keeping illegal duplicate log books to conceal their real hours, using drugs to overcome fatigue, and driving without proper certification - these violations put the driver and everyone else at risk. In other cases truck drivers may drive legally, but make bad decisions that result in injury or death to other drivers on the highway.
Safety studies conducted by the National Transportation Safety Board (NTSB) have documented the role of alcohol and drug use in truck accidents throughout the United States. One study in particular investigated of truck accidents in which the driver of a heavy truck was fatally injured and determined that one-third of fatally injured large truck drivers tested positive for alcohol or other drugs. ( http://www.ntsb.gov/publictn/1990/ss9001.htm )
Fatigue and fatigue-drug interactions were noted as the most common factor in these catastrophic accidents. Truck driver fatigue is a common cause of large truck accidents, but often truck drivers will resort to the use of amphetamines, methamphetamines or other stimulants to try to overcome fatigue. NTSB studies uncovered a strong link between violations of the maximum driving time regulation and drug usage by truck drivers. (http://www.ntsb.gov/publictn/1990/ss9001.htm)