Vehicle Safety Systems Struggle To ‘See’ In Bad Weather: US AAA

New research from US motoring organisation AAA has found moderate to heavy rain affects a vehicle safety system’s ability to ‘see’, which may result in performance issues.

During closed course testing, the AAA simulated rainfall and found test vehicles equipped with automatic emergency braking and travelling at 35 mph (56 km/h) collided with a stopped vehicle 33 per cent of the time, while lane keeping assistance test vehicles departed their lane 69 per cent of the time.

The AAA said ADAS is typically evaluated in ideal operating conditions but testing standards must incorporate real-world conditions that drivers would normally encounter.

“Vehicle safety systems rely on sensors and cameras to see road markings, other cars, pedestrians and roadway obstacles so naturally, they are more vulnerable to environmental factors like rain,” said Greg Brannon, Director of Automotive Engineering and Industry Relations at the AAA.

“The reality is, people aren’t always driving around in perfect, sunny weather so we must expand testing and take into consideration things people actually contend with in their day-to-day driving.”

The AAA, in collaboration with the Automobile Club of Southern California’s Automotive Research Centre, simulated rain and other environmental conditions (bugs and dirt) to measure impact on the performance of ADAS systems like automatic emergency braking and lane keeping assistance. Generally, both systems struggled with simulated moderate to heavy rain.

During testing with a simulated dirty windshield (stamped with a concentration of bugs, dirt and water), minor differences were noted but performance was not negatively impacted. While the AAA’s testing found overall system performance was not affected, ADAS cameras can still be influenced by a dirty windshield.

Previous AAA testing of vehicle safety systems, in closed-course and real-world settings, also showed performance is greatly impacted by driving scenarios, road conditions and vehicle design, finding issues such as:

  • Struggling to stay within a marked lane in moderate traffic, on curved roadways and on streets with busy intersections
  • Failing to stop for pedestrians in common scenarios like crossing in front of a vehicle, a child darting out between two parked vehicles, or walking at night
  • Colliding with a simulated disabled vehicle and instances of coming too close to other vehicles or guardrails

The AAA said its research shows the technology is not a replacement for a fully engaged driver.

“AAA recognises these systems have the ability to lessen the chance of a crash and improve the overall safety of driving,” Brannon said. “Fine-tuning their performance and providing drivers with a more consistent experience will go a long way in unlocking their true potential.”