A series of 150 fatal crashes involving tractor trailers was studied retrospectively. Twenty-five tractor trailer drivers and 63 drivers of other vehicles died and were tested for alcohol. About one-third in each group had blood alcohol concentrations of 0.10% by weight or more. Of 17 tractor trailer drivers apparently responsible for crashes, 8 had illegal alcohol concentrations (0.10% or more). Only 2% of the surviving drivers were charged with driving while intoxicated or impaired. Recommendations include implementation of the federal standard calling for quantitative tests for alcohol, where practicable, on all drivers (including surviving drivers) in crashes fatal to other persons.