The Federal Motor Carrier Safety Administration (FMCSA) has given high priority to research regarding collisions between large trucks (gross vehicle weight > 4,540 kilograms (10,000 pounds)) and other vehicles on the roadway. This research aims to improve knowledge about the high-risk behaviors of truck and passenger vehicle (car) drivers. In 1998, large trucks accounted for 7 percent of the total vehicle miles traveled but were involved in 13 percent of all traffic fatalities (5,374 of 41,471). In these truck crashes, the car’s occupants were much more likely than the truck driver to be killed (78 percent of the fatalities were car occupants) or injured (76 percent of the injuries were sustained by car occupants).(1) Two-thirds of all police-reported truck crashes involved a truck and another vehicle, and 60 percent of all truck crashes involving a fatality were two-vehicle car-truck crashes.(2) To address this critical issue, FMCSA has set a goal to reduce truck involved fatal crashes by 41 percent by 2008. Meeting this goal will require improving truck safety and enhancing truck and car drivers’ behavior and performance.