This synthesis examines and summarizes literature and industry information relating to speed limiters; exploring questions concerning measurable safety impacts, metrics, and degree of benefit, if any. Speed limiters, also described as speed governors, are devices that interact with a truck engine to only permit the attainment of a pre-programmed speed. The purpose is to synthesize data, research, and analyses performed to date in terms of both methodologies employed to assess speed limiters and the actual results, which may be used to guide policy development in North America. The scope of the project encompassed an assessment of the safety efficacy of speed limiters, for commercial motor vehicles in Australia and Europe, as well as in North America and, in addition, for commercial vehicle operations, surveyed truck and intercity and charter bus carriers, that have experience in using speed limiters regarding perceived benefits and/or drawbacks. It is noted that, although this synthesis provides a general understanding of speed limiter use in commercial motor vehicle operations, it does not provide a methodological comparison of before-and-after results applied uniformly across predefined truck and bus fleet operations. An approach to an in-depth empirical study that would gather data from the commercial truck and bus industry with regard to the safety effectiveness of speed limiters is suggested. (Author/publisher)
Abstract