Federal Motor Vehicle Safety Standards; Stability and Control of Medium and Heavy Vehicles During Braking

摘要

This document responds to petitions for reconsideration of final rules that amended FMVSS No. 105, Hydraulic Brake Systems, and FMVSS No. 121, Air Brake Systems, to require medium and heavy vehicles to be equipped with an antilock brake system (ABS). In response to the petitions, this document requires continuous power for trailer ABS systems, in place of the dedicated power and separate ground previously required, and delays the implementation date for the in-cab trailer malfunction indicator by four years. It also extends by three years the period in which exterior ABS failure indicators are required on trailers.