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Automotive & MechanicsAutomatic Emergency Braking: The New Federal Rule
Twenty flashcards on FMVSS No. 127, the NHTSA rule that makes cars brake on their own for vehicles and pedestrians.
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20 cards
- What does FMVSS No. 127 require?
- Automatic emergency braking (AEB), including pedestrian AEB, on light vehicles.
- Which vehicles does FMVSS No. 127 cover?
- Passenger cars, and multipurpose vehicles, trucks and buses of 4,536 kg (10,000 pounds) GVWR or less.
- From when must new light vehicles comply?
- Vehicles manufactured on or after September 1, 2029.
- When must small-volume and final-stage manufacturers comply?
- By September 1, 2030.
- How does the rule define an AEB system?
- It detects an imminent collision with vehicles, objects or road users and automatically controls the brakes to avoid or mitigate it.
- What crashes is FMVSS No. 127 meant to reduce?
- Crashes where drivers do not brake, or do not brake hard enough, to avoid or mitigate the crash.
- How many lives does NHTSA estimate the rule will save?
- At least 362 lives a year, and 24,321 non-fatal injuries mitigated.
- Which law ordered NHTSA to require AEB?
- The Bipartisan Infrastructure Law, section 24208(a).
- At what speeds must AEB work for a vehicle ahead?
- Above 10 km/h (6.2 mph) and below 145 km/h (90.1 mph).
- At what speeds must AEB work for pedestrians?
- Above 10 km/h (6.2 mph) and below 73 km/h (45.3 mph).
- What comes before automatic braking?
- A forward collision warning: an auditory and visual signal of the impending collision.
- What does the warning symbol look like?
- Red and steady burning, using the SAE J2400 crash pictorial symbol.
- How high must the warning sound's frequency be?
- A high fundamental frequency of at least 800 Hz.
- What happens to the radio during the warning?
- In-vehicle audio not related to the warning must be muted or turned down.
- Is AEB tested at night?
- Yes: dark tests at 0.2 lux or less, run with lower beams and separately with upper beams.
- How does NHTSA check that AEB does not brake for nothing?
- A false activation test driving over a steel trench plate of 2.4 m x 3.7 m x 25 mm.
- What if a sensor is blocked or the system fails?
- The system must keep detecting malfunctions, including sensor obstructions, and show a telltale to the driver.
- Does AEB stay off if the driver switches it off?
- No: it must return to its default mode at each new ignition cycle (except in low-range four-wheel drive).
- Who may get a secure control to deactivate AEB?
- Only vehicles owned by a law enforcement agency.
- Since when has NHTSA tested AEB in its New Car Assessment Program?
- Since 2010.
Official sources
NHTSA, via GovInfo (Federal Register)
Final rule: FMVSS No. 127, Automatic Emergency Braking Systems for Light Vehicles (89 FR 39686, May 9, 2024)
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