TRB’s Commercial Truck and Bus Safety Synthesis Program (CTBSSP) Synthesis 16: Safety Impacts of Speed Limiter Device Installations on Commercial Trucks and Buses explores issues associated with speed limiters including measurable safety impacts, metrics, and degree of benefit.  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.  A link to this report can be found at https://www.trb.org/news/blurb_detail.asp?id=9951