The accidents resulted in 207 fatalities. The accident investigations were conducted in California, Colorado, Georgia, Maryland, New Jersey, North Carolina, Tennessee, and Wisconsin. These accidents represented approximately 25 percent of this type of accident nationwide. Results revealed that fatigue and fatigue-drug interactions were involved in more fatalities than alcohol and other drugs alone. Of the 57 drivers who were fatigued, 19 were also impaired by alcohol, other drugs, or both. Violation of the Federal hours of service regulations was strongly associated with drug usage. Drivers with at least one suspended or revoked license were ore likely than other fatally injured drivers to have used drugs of abuse. Findings formed the basis for recommendations to Federal and State agencies, trucking industry trade associations, the truckers' union, law enforcement, and training programs. Details of recommendations, figures, photographs, tables, appended methodological and background information and additional results, and 87 references