A Fleet Operator's Comments on FMVSS 121 Braking System Compatibility

Federal Motor Vehicle Safety Standard (FMVSS) 121 has introduced many new and varied problems for vehicle manufacturers, component manufacturers, and vehicle operators. An area of great concern to vehicle operators, particularly fleets, is the question of compatibility associated with antilock system intermix, old and new vehicle intermix, and control standardization.

This paper discusses the compatibility related problems observed during limited fleet tests and evaluation of FMVSS 121 braking systems. Test data, observations, and possible solutions are presented with emphasis on the need for more extensive investigation in this area to ensure that the goal of FMVSS 121-increased truck safety-is achieved.