Automotive Safety Systems Flashcards

What is the function of 'brake assist' (BA) systems in modern vehicles?

Answer: Detect emergency braking intent and automatically apply maximum brake pressure

Brake assist detects a panic stop by sensing rapid pedal application speed, then automatically amplifies hydraulic pressure to achieve maximum braking even if the driver doesn't press the pedal fully.

In a rear-end collision, which occupant injury mechanism is most specifically addressed by active head restraint (AHR) systems?

Answer: Whiplash injury from hyperextension of the cervical spine

AHR systems move the head restraint forward and upward when the seatback is loaded during a rear impact, supporting the head sooner and reducing the differential motion between head and torso that causes whiplash.

Which vehicle dynamics parameter does Electronic Brake-force Distribution (EBD) continuously adjust to optimize braking?

Answer: Front-to-rear brake force ratio based on vehicle load and deceleration

EBD dynamically adjusts the proportion of braking force applied to the front and rear axles based on measured vehicle load and deceleration, preventing premature rear wheel lockup and optimizing stopping distance.

What is the minimum performance requirement under FMVSS 126 for Electronic Stability Control systems in light vehicles?

Answer: All light vehicles under 10,000 lbs GVWR must be equipped with ESC meeting specified performance criteria

FMVSS 126 mandated that all passenger cars and light trucks with a GVWR of 10,000 lbs or less manufactured after September 1, 2011 must be equipped with ESC meeting the standard's performance and malfunction indicator requirements.

In pedestrian protection testing, what is the primary injury criterion used to assess the risk of lower leg fractures from bumper contact?

Answer: Bending moment and shear force at the mid-shaft of the tibia

Lower leg pedestrian protection tests use a legform impactor measuring bending moment and shear force at the knee, along with tibia acceleration, to assess risk of tibia fracture and knee ligament injury.

What failure mode does 'redundancy' in automotive safety-critical systems primarily address?

Answer: Single-point hardware failures that would otherwise cause complete loss of a safety function

Redundancy ensures that a single-point hardware failure in a safety-critical component (e.g., a brake control module) does not result in total loss of the safety function by providing backup channels or systems.

Which test protocol specifically evaluates a vehicle's structural performance and occupant protection in a narrow, high-speed frontal crash into a rigid object such as a pole?

Answer: IIHS small overlap rigid barrier (SORB) test at 64 km/h

The IIHS small overlap rigid barrier test at 64 km/h engages only 25% of the front structure on the driver's side, replicating crashes into poles or trees and exposing weaknesses not captured by full-width tests.