In January 2004, the Federal Motor Carrier Safety Administration raised the limit of consecutive hours of driving to 11 hours and reaffirmed the change in October of this year. This had a direct impact on crash rates, increasing the risk for truck drivers at the last hours of their shifts. For 60 years, federal rules set the limit to 10 hours, and even then crash rates were 2.5% more likely to happen in the last hour of driving.
Moreover, according to a recent study named: "On the Relationship of Crash Risk and Driver Hours of Service" (conducted by Penn State University Professor Paul Jovanis) the crash risk is very similar in the first six hours of driving but it increases dramatically thereafter, reaching almost 3.5% in the 11th hour. Researchers compared crash and operations records of three large carriers from the third quarter of 2004 with both LTL and truckload operations. The results pointed to an increased risk linked with the new regulation.
Jovanis stated that, considered as a whole, these results reveal important differences in crash risk associated with the two different types of trucking operations: sleeper and non-sleeper. One tentative conclusion is that the rigors of sleeper operations appear to result in a greater decline in performance at extended driving hours than for comparable non-sleeper operations, which raises the chances for an accident.
However, non-sleeper operations are also at a similar risk when the driver is in the road over 7 days with a multi-day schedule, but Jovanis considered that sleeper and non-sleeper should be modeled separately. Whatever the case, multi-day or extended driving periods proved to be important elements in the crash rates and the risk to which truck drivers are exposed every day.