NHTSA has opened rulemaking to amend FMVSS No. 135, the federal Light Vehicle Brake Systems standard, removing the requirement for hand- or foot-operated brake controls in vehicles designed to run exclusively on automated driving systems. The proposal is the fifth Federal Motor Vehicle Safety Standard the agency has moved to revise under its Automated Vehicle Framework, and it leaves every existing braking performance requirement — including stopping distance standards — untouched. Affected ADS-only vehicles would still have to meet the same stopping distance criteria through alternative test procedures, according to the proposed rule; vehicles that keep manual driving controls remain subject to all current FMVSS 135 requirements.
Highlights
- The rulemaking amends FMVSS No. 135, “Light Vehicle Brake Systems” — the fifth FMVSS the agency has moved to update under its Automated Vehicle Framework.
- It removes the hand- and foot-operated brake control requirement only for vehicles with no provision for a human driver.
- Stopping distance performance criteria are retained in full, with compliance demonstrated through alternative test procedures.
- Vehicles that keep manual driving controls remain subject to every existing FMVSS 135 requirement.
What the Rule Removes
FMVSS No. 135 currently requires hand- or foot-operated brake controls. The rulemaking would lift that requirement for vehicles designed never to be operated by a person, while keeping it in force for ADS-equipped vehicles that retain manual controls. NHTSA grouped the brake pedal with other human-driver equipment — windshield wipers and rearview mirrors among them — that a vehicle does not need when no one will ever drive it.
What Stays: Stopping Distance Performance
The performance core of the standard is unchanged. The proposal preserves the existing braking performance requirements, including stopping distance criteria, which affected vehicles must still meet through alternative test procedures. NHTSA said it is separately developing safety performance requirements for AVs in real-world driving scenarios. The agency added that it will continue to use its defect enforcement authority to investigate unsafe ADS behavior and oversee recalls.
NHTSA Administrator Jonathan Morrison tied the proposal to a wider regulatory overhaul. “We are at the cusp of the greatest technological revolution in vehicle technology since the innovation of the Model T,” Morrison said. “If we want America to lead the way, we have to reimagine our regulatory framework. That’s why under Secretary Sean Duffy’s AV Framework, NHTSA is tearing down pointless barriers to innovative designs while strengthening the fundamental safety requirements that matter and holding AV developers accountable for safe performance. This approach will ultimately reduce roadway crashes, prevent fatalities, and increase mobility.”
Where the Update Sits in NHTSA’s AV Rulemaking
The FMVSS 135 proposal, opened this week, is the latest in a series of standard revisions under the Department of Transportation’s Automated Vehicle Framework. NHTSA listed the following progress:
- Safety standards: Proposed updates to transmission shifting (FMVSS 102), windshield defrosting and wiping (103/104), tire placards (110), and now braking (135). The agency said that once these are complete, individual vehicle exemptions may no longer be necessary.
- Exemptions: Streamlined the Automated Vehicle Exemption Program (AVEP) and Part 555 exemption programs for demonstration and commercial fleets, and expanded AVEP to include domestic vehicles.
- Competency standards: Began developing performance standards for AVs intended to meet the Vehicle Safety Act’s objectivity requirements.
- Safety guidance: Began drafting the first major federal safety guidance for AV developers since 2017, working with industry and safety experts.
- Industry engagement: Convened a National AV Safety Forum with automotive and technology safety stakeholders.
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