This report reviews the problem of heavy vehicle speeding (in particular, speeding at greater than 65 mph) and speeding-related crash involvements. The report describes and assesses devices available to control truck speed, and addresses the question of whether the use of speed control devices by heavy trucks should be mandated. The report finds that, by all measures of crash involvement, speeding is not a significant factor in the crash picture of single-unit trucks. Thus, most of the report addresses combination-unit trucks, which present a more complex picture. Non-detectable radar studies show that highway speed limit compliance by combination-unit trucks is poor, but better than that of passenger vehicles. Most trucks that speed travel at just over the posted speed limit. Crash statistics indicate that speeding is generally less involved in combination-unit truck crashes than it is in passenger vehicle crashes. The report describes devices available to control truck speed, and ways that they are applied in commercial fleet settings. The report is supportive of fleet applications of speed-monitoring and speed-limiting devices, but concludes that there is not sufficient justification to consider requiring all heavy trucks to be so equipped. Problem size statistics suggest that the number of target crashes is low, e.g., approximately 30 fatal crash involvements per year for combination-unit trucks. This small crash problem size, together with uncertainties regarding the potential for crash reduction, suggest that the benefits of mandatory speed limitation are questionable. (A)
Samenvatting