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Rulemaking » U.S. DOT/NHTSA - Federal Motor Vehicle Safety Standards; FMVSS No. 105, Hydraulic and Electric Brake System; FMVSS No. 121, Air Brakes - Notice of Proposed Rulemaking
U.S. DOT/NHTSA - Federal Motor Vehicle Safety Standards; FMVSS No. 105, Hydraulic and Electric Brake System; FMVSS No. 121, Air Brakes - Notice of Proposed Rulemaking
Document ID: NHTSA-1999-6550-0001
Document Type: Notice
Agency: National Highway Traffic Safety Administration
On March 10, 1995, NHTSA published a final rule amending the hydraulic and air brake standards to require medium and heavy vehicles to be equipped with antilock brake systems (ABS) to improve the directional stability and control of these vehicles during braking. We supplemented the ABS requirements for truck tractors with a braking-in-
a-curve performance test on a low-coefficient of friction surface, using a full brake application, in both the unloaded (bobtail) condition and with the tractor loaded to its gross vehicle weight rating (GVWR) using an unbraked control trailer.The braking-in-a-curve test was not applied to single-unit trucks or buses or to air-braked trailers because we had performed only limited testing of ABS-equipped
single-unit vehicles. We stated that we would continue research on dynamic performance tests for single-unit trucks, buses, and trailers, and would consider applying performance test requirements to these
vehicles in the future.
The agency is now proposing to apply the braking-in-a-curve dynamic performance test requirement to single-unit trucks and buses that are
required to be equipped with antilock braking systems. After issuing the March 1995 final rule, we tested several ABS-equipped single-unit trucks and buses equipped with both hydraulic and air brakes. We tentatively conclude that the test results confirm that the braking-in-a-curve performance test requirement is practicable for those vehicles. Adopting this requirement would complement the ABS
equipment requirements and stopping distance requirements. Taken together, these requirements would improve the ability of the affected vehicles to stop in a stable and controllable manner. You should submit your comments early enough to ensure that Docket Management receives them not later than
February 22, 2000.
Document Subtype:
Notice of Proposed Rulemaking (NPRM)
Received Date:
December 21 1999, at 12:00 AM Eastern Standard Time
Page Count:
12
Comment Due Date:
December 21 1999, at 11:59 PM Eastern Standard Time
U.S. DOT/NHTSA - Federal Motor Vehicle Safety Standards; FMVSS No. 105, Hydraulic and Electric Brake System; FMVSS No. 121, Air Brakes - Notice of Proposed Rulemaking
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