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May 13, 2024

Pushing the (Automatic) Brakes: NHTSA Adopts Final AEB Rule for Light Vehicles

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On May 9, 2024, the U.S. Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) announced the adoption of a Final Rule (new FMVSS 127) requiring forward collision warning (FCW) and automatic emergency braking (AEB), including pedestrian AEB (PAEB), systems on light vehicles.1 NHTSA explains, “[t]his final rule specifies that an AEB system must detect and react to an imminent crash with both a lead vehicle or a pedestrian.” This is the first substantive Federal Motor Vehicle Safety Standard (FMVSS) standard for advanced driver assistance systems (ADAS) and sets forth very aggressive performance standards for AEB systems on new light passenger vehicles sold on or after September 1, 2029. 

While nearly 100% of new light passenger vehicles sold in model year 2023 had AEB systems that met the standards of the 2016 Memorandum of Understanding for AEB systems tested to NCAP protocols, FMVSS 127 sets forth significantly enhanced performance specifications for AEB systems for light passenger vehicles sold on or after September 1, 2029.

Currently, the NCAP test protocol for FCW conducts tests under scenarios at vehicle speeds up to 72.4 km/h (45 mph) and AEB at vehicle speeds up to 72.4 km/h. There is no requirement that FCW warnings occur at all vehicle speeds, no requirement that AEB braking occur at vehicle speeds above 72.4 km/h, and no requirement for pedestrian AEB (PAEB). 

The Final Rule expands these requirements to require FCW warnings at nearly all vehicle speeds, crash avoidance through AEB support at vehicle speeds up to 100 km/h (62 mph) when manual braking also occurs, crash avoidance through AEB commanded braking at speeds up to 80 km/h (50 mph) when no manual braking occurs and requires PAEB on new vehicles. 

NHTSA summarized the Final Rule with four enumerated requirements: (1) provide FCW at any forward speed greater than 10 km/h (6.2 mph), presented via auditory and visual modalities, with permissible additional warning modes, such as haptic; (2) apply the brakes automatically at any forward speed greater than 10 km/h (6.2 mph) when a collision with a lead vehicle or a pedestrian is imminent, including at speeds above those tested by NHTSA; (3) prevent the vehicle from colliding with the lead vehicle or pedestrian test mannequin when tested according to the proposed test procedures, which would include pedestrian tests in both daylight and darkness and two false positive tests; and (4) provide visual notification to the driver of any malfunction that causes the AEB system not to meet the minimum proposed performance requirements.

NHTSA concludes that the Final Rule is estimated to save at least 362 lives and mitigate 24,321 non-fatal injuries a year. NHTSA additionally concludes in the promulgation of this Final Rule that PAEB is both achievable and necessary. In NHTSA’s words, “[p]edestrian fatalities are increasing, and NHTSA’s testing reveals that PAEB systems will be able to significantly reduce these deaths.” NHTSA does acknowledge that this Final Rule is ambitious based on manufacturers’ responses to adding lead vehicle AEB and other technologies to NCAP. 

Regardless of NHTSA’s acknowledgement, we expect plaintiff’s counsel will argue that FMVSS 127 mean that all rear-impact crashes (in vehicles meeting FMVSS 127) are caused by a defect in the vehicle’s AEB system, that new vehicles sold between today and September 1, 2029, should meet FMVSS 127, and that most (if not all) pedestrian fatalities are the result of defects in the vehicle’s AEB system. 

Separately, because the Final Rule requires FCW, AEB, and PAEB to operate at a much wider range of vehicle speeds, we expect to see an increase in consumer/warranty claims related to allegedly defective AEB systems. We are already seeing many warranty claims related to alleged unexpected/unnecessary AEB warnings and braking activation. We expect to see even more once FMVSS 127 comes into effect. 

Bowman and Brooke’s automotive practice attorneys currently defend many OEMs in ADAS performance cases and know how to explain what ADAS systems (including FCW, AEB, and PAEB) are and what they do not do before courts and juries around the country. We are ready to address the new FMVSS No. 127 standards and put the minimum requirements into context during litigation. We know how to explain that AEB does not replace the responsibility of a driver to safely operate the vehicle, that AEB systems are not automated/self-driving systems, and that there are many good reasons why AEB might not operate in a given crash scenario. We understand the engineering considerations OEMs must consider when introducing ADAS systems. We stand ready to address plaintiff’s claims about what AEB and PAEB systems could do in any given collision and to explain the benefits and design limitations of these systems. 

Catch up on the 2023 proposal here, "Stopping on a Dime: NHTSA proposal requires Automatic Emergency Braking and Pedestrian Automatic Emergency Braking for Light Vehicles."



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