Day and night performance differences in detection and deceleration by pedestrian automatic emergency braking systems

Area of Science:

• Road Safety Engineering
• Automotive Technology
• Human Factors in Transportation

Background:

• Increasing pedestrian fatalities necessitate advanced vehicle safety systems.
• Pedestrian Automatic Emergency Braking (P-AEB) systems offer potential crash mitigation.
• P-AEB effectiveness varies, particularly under challenging nighttime visibility conditions.

Purpose of the Study:

• To evaluate the real-world effectiveness of P-AEB systems across diverse visibility conditions.
• To quantify P-AEB performance differences between daytime and nighttime scenarios.
• To identify factors influencing P-AEB system performance, including lighting and vehicle characteristics.

Main Methods:

• Analysis of 2,494 P-AEB tests (1,654 nighttime, 840 daytime) from the Insurance Institute for Highway Safety.
• Utilized a random-effects Heckman sample selection model to estimate detection and deceleration.
• Incorporated variables for pedestrian movement, vehicle type, fuel, and size.

Main Results:

• Daytime P-AEB detection rates reached approximately 98%, compared to 87% (low beam) and 93% (high beam) at night.
• Nighttime crashes occurred more frequently (23% on low beam vs. 10% daytime) and at higher speeds.
• Halogen low beams reduced P-AEB detection capability by up to 43% compared to daytime.

Conclusions:

• Current P-AEB systems demonstrate reduced effectiveness during nighttime driving.
• Significant improvements are needed for P-AEB systems to perform reliably in low-light conditions.
• Vehicle and pedestrian factors influence P-AEB performance, requiring further investigation for optimized pedestrian safety.