# Federal Motor Vehicle Safety Standards; Hydraulic and Electric Brake Systems
> **National Highway Traffic Safety Administration** · Final rule. · Published 2004-12-17 · Effective 2005-01-18 · 69 FR 75486
## Document
- **Document number:** 04-27595
- **Category:** fmvss
- **Sub-agency:** National Highway Traffic Safety Administration
- **Federal Register citation:** 69 FR 75486
- **CFR reference:** 49 CFR 571
- **Publication date:** 2004-12-17
- **Effective date:** 2005-01-18
- **DOT docket:** Docket No. NHTSA-04-19892
## Abstract

In this document, NHTSA is establishing an option in the Federal motor vehicle safety standard on hydraulic and electric brake systems to permit the use of a roll bar structure during specified testing of brake systems in single unit trucks and buses. This option is already available for similar testing of air braked trucks and buses. Permitting the use of a roll bar structure will help protect drivers and technicians in the event of a rollover during testing of hydraulically-braked trucks and buses. The safety of drivers and technicians is a primary concern during vehicle testing. The use of a roll bar structure offers protection to the drivers and technicians performing brake tests conducted at lightly loaded vehicle weight.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2004/12/17/04-27595/federal-motor-vehicle-safety-standards-hydraulic-and-electric-brake-systems)
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