Pursuant to a congressional request, GAO reviewed the Army's M939 series 5-ton tactical cargo truck, focusing on the: (1) extent to which accidents involving the truck have occurred; and (2) results of Army studies on the truck's design and its plans to address any identified deficiencies.

GAO noted that: (1) GAO's analyses and an Army analysis indicate a higher rate of accidents involving the M939 series 5-ton tactical cargo truck than other comparison vehicles; (2) GAO's analysis of January 1987 through June 1998 accident data showed that, while M939s made up an average of about 9 percent of the Army motor vehicle fleet during that time, about 34 percent of the fleet's accidents resulting in fatalities of vehicle occupants involved these trucks; (3) 44 percent of accidents that involved a rollover and resulted in fatalities of vehicle occupants involved the M939; (4) GAO's comparison of Department of Transportation accident statistics and M939 accident statistics showed that over a 10-year period, the fatality rate for occupants of the M939 averaged about 30 times higher than the fatality rate for occupants of comparably sized commercial trucks; (5) an Army Safety Center analysis found that the chance of a fatality in a M939 was 3 to 21 times higher than in other similar military trucks in the Army motor vehicle fleet--the M34/M35 series 2 1/2 ton trucks; (6) the Army plans to spend an estimated $234 million on various modifications to improve the M939's safety and operational performance; (7) based on the results of studies into the root causes of M939 accidents, the Army concluded that the overall truck design was sound, but some modifications were necessary; (8) the Army plans to use the $234 million to add anti-lock brake kits, alter brake proportioning specifications, upgrade the truck's tires, install cab rollover crush protection, and modify the accelerator linkage; (9) most modifications will be completed by 2005; and (10) the M939s will remain in service as these modifications are made.