NHTSA published their final rule on AEB in the U.S. Federal Register this past 26 November, enacting new Federal Motor Vehicle Safety Standard № 127, with effect from 27 January 2025. New vehicles built from 1 September 2029 (the 2030 models) will have to be equipped with AEB systems. The only exception is vehicles “produced by small-volume manufacturers, final-stage manufacturers, and alterers”; those will have an additional year, and will have to be equipped with compliant systems starting on 1 September 2030 (the ’31 models).
The deadline to file a petition for reconsideration was 10 January—which has already passed, and NHTSA’s response to them is visible at the linked Federal Register publication. The Alliance for Automotive Innovation; Toyota; VW, and Scuderia Cameron Glickenhaus (who describe themselves as “a boutique manufacturer of exotic high-performance racing and road cars”) filed petitions for reconsideration. Hyundai sent NHTSA a letter commenting on the proposed rule, which the agency treated as though it were a petition for reconsideration. A further petition was sent in by Autotalks, who say they make chipsets for “advanced, secure V2X communication”. However, it was submitted after the deadline, so NHTSA are treating it as its own start-from-scratch petition for rulemaking.
Some contested points of the proposed regulation were granted. In summary:
- petitioners wanted explicit definitions for terms “operate” and “imminent” as used in the standard. NHTSA declined to do so, on grounds that “imminent” is used in its ordinary plain meaning, and the language of the regulation already defines how the system must “operate”. The agency did decide to adjust the language of the standard with regard to “imminent”, in recognition that the specified performance test doesn’t look at AEB activation timing.
- The agency found, after reviewing the petitions, that one of their test scenarios inadvertently made parts of the standard more stringent than intended; the relevant language has been adjusted.
- NHTSA also adjusted the language of the standard to clarify the specifications for the forward collision warning visual and audible signals.
Other contested points were denied. Petitioners wanted NHTSA to ease up on the requirement that an AEB-equipped vehicle make no contact with the lead vehicle or pedestrian. Specifically, they wanted contact to be allowed at or below 10 km/h. NHTSA said no, on grounds that the no-contact requirement is feasible and meets the need for safety. Petitioners asked that multiple test runs be permitted to achieve the no-contact performance—for example, no contact on five out of seven runs could be considered a pass. NHTSA said no to this, too, on the same grounds: the standard as put forth is feasible and meets the need for safety.
Petitioners also wanted more specificity on fault-indicator warning lights; NHTSA declined to provide it, saying the rule as written meets the legal requirements for Federal Motor Vehicle Safety Standards. Another rejection: petitioner requests to be permitted to provide a control by which the driver could disable the system. One petitioner—it was the “boutique manufacturer of exotic high-performance racing and road cars”—asked that AEB not be required on cars with manual transmissions; NHTSA said there’s no need for any such an exemption, because manual-transmission vehicles with AEB are already a thing. The same petitioner wanted the rule relaxed for small-volume makers like themselves; NHTSA said no and referred to existing provisions by which very low-volume car makers can petition on a case-by-case basis for relief from specific requirements. And at least one petitioner said NHTSA failed to fully consider the costs involved with equipping vehicles with AEB; NHTSA’s response: “Yes, we did”.
The final rule is thorough and detailed. It includes stringent system performance requirements, system configuration and self-check requirements, and two different false-activation tests. Have a close look at the Federal Register publication linked at the start of this article; give it a good read-through. We’re all going to have to be conversant with it in a few short years!
