The National Highway Traffic Safety Administration (NHTSA) published a Notice of Proposed Rulemaking (NPRM) in the June 13, 2023 Federal Register (F.R. Vol. 88 No. 113) (NHTSA-2023-0021). This NPRM would adopt a new Federal Motor Vehicle Safety Standard -127 Automatic Emergency Braking Systems for Light Vehicles (FMVSS - 127) and PART 596 -Automatic Emergency Braking Test Devices to require Automatic Emergency Braking (AEB), including pedestrian (PAEB) systems on passenger cars and light trucks. AEB systems use various sensor technologies and subsystems working together to detect when the vehicle is in a crash imminent situation, to automatically apply the vehicle brakes if the driver has not done so, or to apply more braking force to supplement the driver’s braking to prevent/lessen an imminent crash with a lead vehicle or pedestrian.
The NPRM actions promote NHTSA’s goal to equip vehicles with AEB and PAEB, advance DOT’s January 2022 National Roadway Safety Strategy that identified requiring AEB on new passenger vehicles as a key Departmental action, and respond to a mandate under the Bipartisan Infrastructure Law directing the Department to promulgate a rule to require that all passenger vehicles be equipped with an AEB system. This NPRM proposes to address the significant safety problem by frequency and severity of both rear-end and pedestrian crashes. NHTSA’s decision to mandate AEB is based on decades of research and development beginning in the 1990s. Methods by which AEB system performance could be assessed and tested were part of the 2010 New Car Assessment Program (NCAP). NHTSA incorporated AEB into NCAP beginning in model year 2018. This has achieved success, with approximately 65% of new vehicles meeting the lead vehicle test procedures included in NCAP. Separate from NCAP, in March 2016, NHTSA and Insurance Institute for Highway Safety (IIHS) announced a commitment by 20 manufacturers representing more than 99 percent of the U.S. light vehicle market to equip low-speed AEB as a standard feature on nearly all new light vehicles not later than September 1, 2022. This voluntary commitment has resulted in approximately 90 percent of new light vehicles having an AEB system.
NHTSA believes that gaps in market penetration will exist for the most highly effective AEB systems. NHTSA has also observed that, in the case of both electronic stability control and rear visibility, only approximately 70 percent of vehicles had these technologies during the time they were part of NCAP. While NCAP serves a vital safety purpose, NHTSA also recognizes its limitations and concludes that only regulation can ensure that all vehicles are equipped with AEB that meet the proposed performance requirements. These considerations are of even greater weight when considering whether to require a system that can reduce pedestrian crashes. Addressing earlier petitions, NHTSA stated that the non-regulatory activities being undertaken at the time would make AEB standard on new light vehicles faster than could be achieved through a regulatory process. NHTSA stated that it would monitor vehicle performance in NCAP and the industry’s voluntary commitment, and initiate rulemaking if the need arose.
NHTSA used the Fatality Analysis Reporting System (FARS) and Crash Report Sampling System (CRSS) databases to derive a target population and to determine the portion of the rear-end and pedestrian fatality population that could be affected. They have tentatively concluded that AEB technology could potentially address up to 3,036 fatalities (394 lead vehicle and 2,642 pedestrian), 160,309 injuries (142,611 lead vehicle and 17,698 pedestrian), and 1,119,470 property damage only crashes (only lead vehicle). This represents 15 percent and 14 percent of fatalities and injuries resulting from rear end crashes, respectively and 43 percent and 28 percent of fatalities and injuries from pedestrian crashes. These crashes also represent 8.4 percent of total roadway fatalities, 5.9 percent of total roadway injuries, and 23 percent of property damage only crashes. A final factor weighing in favor of requiring AEB is that the technology is at a significantly more mature level than what it was at the time of the voluntary commitment or when it was introduced into NCAP. NHTSA's most recent testing has shown that higher performance levels than those in the voluntary commitment or the existing NCAP requirements are now practicable.
The proposed standard includes four requirements for AEB systems for both lead vehicles and pedestrians. First, vehicles would be required to have an AEB system that provides the driver with a Forward Collison Warning (FCW) at any forward speed greater than 10km/h (6.2mph). NHTSA is proposing that the FCW be presented via auditory and visual modalities when a collision with a lead vehicle or a pedestrian is imminent. Second, vehicles would be required to have an AEB system that applies the brakes automatically at any forward speed greater than 10km/h (6.2mph) when a collision with a lead vehicle or a pedestrian is imminent. Third, the AEB system would be required to prevent the vehicle from colliding with the lead vehicle or pedestrian test mannequin when tested according to the proposed standard's test procedures. These track test procedures have defined parameters that will ensure that AEB systems prevent crashes in a controlled testing environment. There are three general test scenarios each for testing vehicles with a lead vehicle and four scenarios for testing vehicles with a pedestrian test mannequin. The final proposed requirement is that a vehicle must detect AEB system malfunctions and notify the driver of any malfunction that causes the AEB system not to meet the minimum proposed performance requirements. Malfunctions would include those attributable to sensor obstruction or saturation, such as accumulated snow or debris, dense fog, or sunlight glare. The proposal only includes a specification that the notification be visual.
The NPRM requirements fall into these categories:
- Lead Vehicle AEB System Requirements
- Forward Collision Warning Requirements - FCW Modalities, FCW Auditory Signal Characteristics, FCW Visual Signal Characteristics, and FCW Haptic Signal
- Lead Vehicle AEB - Performance Test Requirements for Stopped Lead Vehicle Scenario Test Speeds, Slower-Moving Lead Vehicle Scenario Test Speeds, Decelerating Lead Vehicle Scenario Test Speeds, and Subject Vehicle Brake Application
- PAEB System Requirements
- PAEB FCW Requirements
- PAEB Performance Test Requirements - PAEB Scenario Descriptions, Overlap, Vehicle and Pedestrian Surrogate Travel Speeds, Crossing Path Scenario Testing Speeds, Stationary Scenario Testing Speeds, Along Path Scenario Testing Speeds, and PAEB Darkness Testing
- Alternatives to No-Contact Performance Test Requirements
- False Activation Requirements - Steel Trench Plate False Activation Scenario, Pass-Through False Activation Scenario, and Potential Alternatives to False Activation Requirements
- Malfunction Detection Requirements
- AEB System Disablement
- AEB System Performance Information
The NPRM proposes vehicles manufactured on or after September 1, four years after the publication date of a Final Rule, would be required to meet all requirements. Vehicles manufactured on or after September 1, three years after the publication date of a Final Rule, but before September 1, four years after the publication date of a Final Rule, would be required to meet all requirements except that lower speed PAEB performance test requirements specified in S5(b) would apply. Small-volume manufacturers, final-stage manufacturers, and alterers would be provided an additional year (added to those above) to meet the requirements of the Final Rule. Early compliance is permitted but optional.
In addition to specific requests for comment on items in this NPRM, NHTSA seeks comments and suggestions on all aspects of this proposal and any alternative requirements that would address this safety problem. NHTSA also requests comments on the proposed lead time for meeting these requirements, and how the lead time can be structured to maximize the benefits that can be realized most quickly while ensuring that the standard is practicable.
Comments for this NHTSA NPRM are required by August 14, 2023.
The NHTSA NPRM for Parts 571 and 596 are available on InterRegs.NET for our US Federal subscribers and are also available at www.selectregs.com.