||The objective of this research project was to examine the efficacy of the new restart rule promulgated as partof the Hours of Service of Drivers Final Rule, published on December 27, 2011, with a compliance date of July 1, 2013. Under the new restart rule, if commercial motor vehicle (CMV) drivers choose to use a provision allowing “restart” of the 60- or 70-hour duty-cycle limit, they are required to include at least two ighttime periods (from 1 a.m. until 5 a.m.) in their restart breaks in order to have sufficient time for sleep recuperation before beginning another duty cycle. To investigate the efficacy of the new rule, a naturalistic field study was conducted (prior to the compliance date) to assess fatigue in drivers working their normal schedules and performing their normal duties. During this study, researchers performed a comparison of driver fatigue during duty cycles preceded by a restart break with only one nighttime period versus duty cycles preceded by a restart break with two or more nighttime periods. Findings included the following
results, which constitute evidence in support of the efficacy of the new restart rule:
1. Drivers affected by the new rule were primarily nighttime drivers. The new rule thus targets those drivers who are at the greatest risk of fatigue.
2. Drivers affected by the new rule reverted to a predominantly nighttime sleep schedule during the restart break. Extending the restart break for drivers affected by the new rule to include an additional nighttime period thus provides them with greater opportunity for sleep recuperation.
3. Drivers who would have already been compliant with the new rule showed less fatigue than those affected by the new rule. This implies that having at least two nighttime periods (from 1 a.m. until 5 a.m.) in the restart break helps to mitigate fatigue.