Research on the Safety Impacts of Speed Limiter Device Installations on Commercial Motor Vehicles: Phase II Draft Final Report

摘要

The purpose of this project was to identify the impacts of implementing speed limiters (SL) in commercial vehicle fleet operations. These impacts may be related to safety through a reduction in the number and/or severity of crashes, and/or address operational issues. This report is the second report of a two-phase approach. Phase I centered on a detailed literature review that updated and expanded on the recent Transportation Research Boards Synthesis Report on the Safety Impacts of Speed Limiter Device Limitations on Commercial Trucks and Buses. The current study involved a series of additional tasks focused on a detailed research design and analysis, a peer review process, evaluation of speed limiter implementation, best practices applications, and identification of carrier, insurer, and enforcement official perspectives related to SL implementation. The primary safety analysis was a focus on the reduction in truck crashes that could have been avoided and/or mitigated with an active SL installed. This was the first study to use actual truck crash data collected directly from truck fleets, representing a wide array of crashes. More specifically, the study included data from 20 truck fleets, approximately 138,000 trucks, and analyzed more than 15,000 crashes. The findings showed strong positive benefits for SLs. First, in terms of safety benefits, results indicated that trucks equipped with SLs had a significantly lower SL-relevant crash rate (approximately 50 percent) compared to trucks without SLs. Second, the cost of the technology is negligible and would not be expected to be cost-prohibitive for fleets/owners. The current study went further than any other research previously conducted in this domain and provides important data on the efficacy of SLs in reducing SL-relevant crashes.