Heavy Truck Cab Safety Study

Nearly 1000 occupants of large trucks die each year in traffic accidents. Examination of yearly trends shows about a 25% decline in tractor-driver fatalities from 674 in 1984 to 508 in 1987. Over that same period of time, reported restraint use by tractor drivers involved in fatal accidents increased from 9.6% to 37.3%. The primary factors associated with tractor driver fatalities remain the same as identified in earlier studies. About 80% are single vehicle accidents. Rollover is identified as the most harmful event in 41.4% and frontal impact is the most harmful event in 40.3%. Thirty-four percent of the fatally injured tractor drivers were ejected and 21.5% required extrication. Fire on the truck was associated with 16.2% of the tractor driver fatalities.

The recent TIFA data on restrained truck drivers indicates that restraint use reduces the probability of fatality by about 77%. However, this estimate must be tempered by the evidence of over-reporting of restraint use on police accident reports. Information obtained through a review of 186 National Transportation Safety Board (NTSB) reports on truck driver fatalities in eight states indicated that there was not sufficient occupant survival space in about 65% of the collisions examined. Forty-two percent were judged to be not survivable because of the severity of the impact. Restraint use alone appears sufficient to alter the outcome of only about 27%. Cab structural modifications sufficient to maintain adequate survival space, particularly in rollover, will be required in order to address an additional 23% that appeared survivable.