Abstract
Using data from the 1997 survey of drivers conducted by the University of Michigan Trucking Industry Program, factors were identified which substantially affect three safety measures: accidents, moving violations, and hours of service violations. The variables used include both operational characteristics (firm size, trailer type) and personal characteristics (age, race, union status). Using both basic descriptive statistics and probit estimation, it was found that the variables that have the most impact on the three safety measures are operational in nature, not individual characteristics. (A)