AEB systems, as defined in the proposal, automatically apply the vehicle brakes if the driver fails to brake, or apply greater force to supplement the driver's braking if a collision with a vehicle or pedestrian is imminent. The rule would apply to passenger cars, trucks, and buses with a GVWR of 10,000 pounds or less. 

The proposal includes a phase-in schedule for new vehicles.  Beginning on September 1 three years after publication of the final rule, all new vehicles will be required to meet all requirements except lower speed PAEB test requirements.  Beginning on September 1 four years after the publication date of the final rule, all new vehicles will be required to meet all aspects of the proposed requirements.  NHTSA also gives manufacturers the option to comply early with the new requirements.

Specifically NHTSA proposes the following performance requirements, for both AEB and PAEB systems:

• Lead Vehicle AEB System Requirement: Vehicles must have FCW and AEB braking systems that are able to continuously function and apply service brakes when a collision with a vehicle or object is imminent at any forward traveling speed greater than 6.2 miles per hour (mph).

• FCW Requirement: AEB-equipped vehicles must have a warning functionality that provides a warning to the vehicle operator if a forward collision with a lead vehicle is imminent and must function at forward traveling speeds greater than 6.2 mph.

• Lead Vehicle AEB Performance Test Requirement: The proposal would establish required tests for three specific scenarios: stopped lead vehicle, slower-moving lead vehicle, and decelerating lead vehicle, with a proposed full collision avoidance performance test criterion. The AEB system must automatically brake or supplement insufficient manual braking to avoid contact with the lead vehicle in each scenario.

• PAEB System Requirements: PAEB systems must warn a vehicle operator and intervene when a pedestrian is in the vehicle’s forward path at any forward traveling speed greater than 6.2 mph.

• PAEB FCW Requirement: NHTSA proposed the same FCW requirements for lead vehicle AEB and PAEB, including auditory and visual warning modalities and functionality at any forward traveling speed greater than 6.2 mph.

• PAEB Performance Test Requirement: The vehicle must completely avoid a collision with a pedestrian test mannequin during three test track scenarios: (1) crossing the path of the vehicle; (2) stationary within the path of the vehicle; and (3) moving along the travel path of the vehicle. Some proposed test scenarios in darker lighting conditions and at lower speeds have a longer phase-in time (four years rather than three).

AEB test procedures will build on existing FCW, crash imminent braking (“CIB”), and dynamic brake support (“DBS”) procedures used in the New Car Assessment Program (“NCAP”), with higher speed performance requirements.  Testing is required under daylight and darkness lighting conditions, which is especially important for PAEB testing. Notably, the proposed rule expands on current NCAP recommendations and testing procedures, and requires AEB systems as a standard feature.  Twenty manufacturers (more than 99% of the U.S. light vehicle market) already committed to installation of AEB systems in a 2016 voluntary commitment. However, the proposed rule goes beyond the voluntary commitment by requiring a PAEB system as well as an AEB system.

In addition to the performance requirements, NHTSA also proposed “false-positive” tests to establish minimum performance in two scenarios when braking is not warranted: (1) steel trench plate and (2) vehicle pass-through test scenarios.  These tests are intended to establish a system baseline and differentiate between a real threat and non-threat to avoid false activation.

Finally, NHTSA proposed requirements for the AEB system including data recording and storage as well as detection requirements.  For example, significant AEB activations (e.g., an AEB event resulting in a speed reduction greater than 12 mph would activate the recording and store information such as date, time, engine hours, activation speed, exit speed, location, and camera image data.  NHTSA specifically seeks comment on the data collection approach and the type of information collected.  The NPRM also would require that AEB systems detect malfunctions and provide a warning to the vehicle operator in the event of any system malfunction.  However, NHTSA is not proposing a specific AEB malfunction indicator telltale. 

NHTSA requests comments on the following additional topics:

• Proposed three- and four-year lead times

• Alternatives to the no-contact criterion for lead vehicle and pedestrian performance tests and the permissible collision speed to prevent serious injuries and fatalities

• Whether and how NHTSA could finalize a rule without AEB and PAEB false activation test requirements

• Modes of driver warnings, malfunction indicator for the AEB system, and display options, including warnings in the instrument panel versus a head-up display

• Sufficiency of proposed test track and performance test constants (including test mannequins and vehicles) to address the risks for real-world pedestrian crash scenarios

Comments on the NPRM are due by August 14, 2023.

Authored by Allisa Newman, Hannah Graae, Sue McAuliffe, and Marissa Shaw.

References

1 88 Fed. Reg. 38632 (June 13, 2023).