# Federal Motor Vehicle Safety Standards: Air Brake Systems
> **National Highway Traffic Safety Administration** · Final rule. · Published 2001-12-12 · Effective 2002-01-11 · 66 FR 64154
## Document
- **Document number:** 01-30636
- **Category:** fmvss
- **Sub-agency:** National Highway Traffic Safety Administration
- **Federal Register citation:** 66 FR 64154
- **CFR reference:** 49 CFR 571
- **Publication date:** 2001-12-12
- **Effective date:** 2002-01-11
- **DOT docket:** Docket No. NHTSA 99-5045
## Abstract

NHTSA is amending its air brake standard to correct an inconsistency between two provisions concerning emergency brake stops, provide that single-unit truck axles should not be overloaded, clarify the wheel-lock provisions by adding a definition of Atandem axle," and to permit the use of roll bars on vehicles undergoing brake testing. This rulemaking was initiated in response to a petition for rulemaking from the Truck Manufacturers Association.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2001/12/12/01-30636/federal-motor-vehicle-safety-standards-air-brake-systems)
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