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

This document responds to petitions for reconsideration of final rules that amended Standard No. 105, Hydraulic Brake Systems, to require medium and heavy vehicles to be equipped with an antilock brake system (ABS). In response to the petitions, this document permits hydraulically-braked vehicles with a gross vehicle weight rating (GVWR) greater than 10,000 pounds but less than 19,501 pounds to be equipped with a single wheel speed sensor in the driveline to control wheel slip at the drive axle and permits rear tag axles to lock up. Additionally, this document allows motor homes with a GVWR of 22,500 pounds or less to use a single rear drive axle wheel speed sensor if they are manufactured before March 1, 2001, after which date new motor homes must meet the same ABS requirements as other hydraulically-braked trucks and buses.