There is a need to quantitatively and qualitatively associate crash occurrence with a range of commercial truck driver characteristics, including hours of driving and hours worked over multiple days. The need arises because of the desire to continue to refine Federal hours-of-service (HOS) regulations for truck drivers. An additional factor is the inconsistent and sometimes contradictory findings of truck driver safety research. This research used the probability of a crash after a certain amount of time driving given no crashes until that time. Carrier-supplied driver logs for periods of 1—2 weeks prior to each crash were used and compared to a random sample (two drivers) of non-crash-involved drivers selected from the same company, terminal, and month using a case-control logistic regression formulation. Data were separated into truckload (TL) and less-than-truckload (LTL) analyses because previous research indicated differences in crash contributing factors for these two segments of the trucking industry. Considering all the data, there is a consistent increase in crash odds as driving time increases. LTL drivers experienced increased crash odds after the 6th hour of driving. Breaks from driving reduced crash odds. In particular, a second break reduced crash odds by 32 percent for TL drivers and 51 percent for LTL drivers. There was, however, an increase in crash odds associated with the return to work after a recovery period of 34 hours or more. (Author/publisher)
Abstract