New NHTSA high-speed/pedesterian AEB Rule
NHTSA has a new rule out requiring high-capability Automatic Emergency Braking (AEB) in new vehicles from 2029. Some key points from an initial read-through of the new NHTSA AEB Rule document are below.
NHTSA points out that the “vast majority of fatalities, injuries, and
property damage crashes occur at speeds above 40 km/h (25 mph), which
are above those
covered by the voluntary commitment [to install current AEB systems].”
And they point out that only regulation via FMVSS rather than using the
NCAP star rating approach can ensure that all vehicles are equipped with
effective AEB. They motivate inclusion of Pedestrian AEB (PAEB) in darkness by pointing out that more than 3/4 of pedestrian fatalities occur in other than daylight conditions. They also obliquely point out that vehicle buyers are
not incentivized to pay for a pedestrian protection feature unless it is
required.
The car company push-back to the earlier proposed rule is summarized as: “a no-contact
performance requirement is not practicable and increases the potential for unintended
consequences such as inducing unstable vehicle dynamics, removing the driver’s authority,
increasing false activations, and creating conditions that limit bringing new products to market.” (see page 30) A thorough discussion of industry comments runs pages 49-232. An interesting NHTSA comment is: “The agency conducted PAEB research with six model year 2023 vehicles (from six different manufacturers) using the proposed performance requirements and test procedures. The results demonstrated that at least one vehicle was able to meet all performance requirements of this final rule.”
The new rule covers:
Vehicles up to 10,000 poundsMitigate crashes into both lead vehicles and pedestriansUltimately this only requires passing a specified set of testsNHTSA might do recalls later for behaviors that present “unreasonable risk” beyond the specified tests
Key requirements:
AEB applies brakes automatically at forward speeds above 6 mph (10 kph)No contact with pedestrians up to to 45 mph (PAEB)No contact with lead vehicle up to 62 mph / operation with contact up to 90 mph (AEB)Darkness included for PAEB testing; only daylight for lead vehicle AEBTwo tests for false activation (steel trench plate, between two parked vehicles), limit of 0.25g to any phantom braking that occurs in those testsLead vehicle testing limited to 50 mph speed differential (AEB)Visual notification of malfunction (malfunction indicator light)Dedicated manual disable switch for driver use is prohibited, but it might be disabled automatically for towing, snow plowing, low-range 4WD, ESC turned off, etc.
Notes and things to ponder:
Less capable AEB is already on new cars and providing benefits. Will these new requirements bring unforeseen risks or compromise those benefits somehow?This is a follow-up to a proposed rule that received almost 1000 comments (see the partial commenter list on pages 28-29), so the industry had their chance to register complaints and point out flaws in the plan. This new rule is an incremental change on that proposal in response to comments.”cost per equivalent life saved of
between $550,000 and $680,000, which is far below the Department’s recommended value of a
statistical life saved, of as $11.6 million in 2020 dollars”Cyclists are not included as either “vehicles” or “pedestrians”Phantom braking will be a concern and I’ll bet we see recalls if it becomes excessive for some models”NHTSA estimates that systems can achieve the requirements of this final rule primarily
through upgraded software, with a limited number of vehicles needing additional hardware.” This notes that most cars have radars, and assumes adding radar to all cars+new software will suffice for complianceI’m sure this NHTSA statement will generate controversy: “NHTSA does not expect that false activation would occur for well-designed systems.” However, in practice this is not an absolute requirement, but rather ammunition for NHTSA to use in a recall if false activations get out of hand.This rule is required by the Bipartisan Infrastructure Law, showing that getting big safety changes is helped when Congress acts to give NHTSA the impetus (and political air cover) to act.An additional thought: Perhaps car makers should create a UL 4600-style safety argument that their AEB/PAEB system is acceptably safe. That could easily head off risks from deploying an unsafe system as well as give them ammunition if an unlucky set of mishaps stimulates a NHTSA recall process.
