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Tuesday, July 16, 2024 | Back issues
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Autonomous cars are slightly safer than human drivers, study says

Records on thousands of accidents on California’s public roads show when and where autonomous vehicles are safer than human-driven vehicles, but researchers stress the importance of driver participation.

(CN) — University of Central Florida researchers tested autonomous and human-driven cars with California accident data.

Because California’s Department of Motor Vehicles allows autonomous vehicle (AV) testing on its public roads, Mohamed Abdel-Aty and Shengxuan Ding had access to 2,100 AV accident records and 35,133 human-driven vehicle (HDV) accident records. According to their study published Wednesday in Nature, these records had information on accident types, road and environmental conditions, pre-accident vehicle movements and accident outcomes.

The researchers found a general year-over-year rise in both annual miles traveled by AVs and the number of AV accidents on California’s public roads, with the exception of the decline seen in 2020, likely attributable to the Covid-19 pandemic.

Beyond the number of accidents, Abdel-Aty and Ding found disparities on when AV and HDV accidents happened.

Whether autonomous or human-driven, car accidents mostly happened while driving straight ahead, accounting for 56% of AV accidents and 58% of HDV accidents. Meanwhile, the researchers said that previous traffic events such as work zones, disabled vehicles and spilled cargo led to 5% of AV accidents, but only 1.3% of human-driven accidents, a leg up over autonomous vehicles.

Regarding concentration, however, the researchers found that inattention and poor driving behavior caused 1.8% of AV accidents, but 19.8% of HDV accidents.

As for the environmental factor, most accidents involving both AVs and HDVs occurred under clear weather conditions, though HDV accidents happened slightly more frequently at 83% compared to AVs’ 73%. The researchers wrote that there is a 5.25 “higher probability of [AV] accident than HDV accident” at dawn or dusk, though, likely because “the sun’s shadows and reflects may confuse sensors” on cars.

Rainy conditions also troubled AVs, where their accidents happened under rain 11% of the time while HDV accidents only happened during rain 5% of the time.

Although they are generally safer than HDVs now, Abdel-Aty and Ding believe that AVs’ safety can improve even greater with technological advancements.

The researchers said that advanced driving systems are generally safer than HDVs in most accident scenarios, because the systems have better track records with object detection and avoidance, precision control and decisionmaking.

With a holistic approach involving advanced sensors, robust algorithms and smart design conditions, the researchers believe that advanced driving systems can improve safety under dawn, dusk or turning conditions. Also, Abdel-Aty and Ding suggested enhancing weather and lighting sensors, implementing redundancy measures and effectively integrating sensor data to make AVs safer in challenging scenarios.

Still, the researchers stressed that they need to do more work.

One major constraint on their research was that they did not know what advanced driving system a vehicle had at the time of its accident. In future studies, the researchers hope they will find that data and incorporate information about right-of-way at intersections, yield signs, stop signs, priority signals and traffic lights to better compare AVs and HDVs. Also, Abdel-Aty and Ding hope to include AV experts in future research, as they can identify and report on the factors that contribute to safety differences between AVs and HDVs.

That said, Ding was clear that their work focused on road safety, not driver replacement.

“It is crucial for the general public to understand that so far AVs are designed to assist drivers, not replace them entirely,” said Ding via email. “While AV systems greatly enhance driving safety and convenience, drivers must stay attentive and engaged.”

Ding added, “This study highlights the importance of the driver's active participation alongside AV technology to ensure safe and effective vehicle operation, though the degree of participation would depend on the level of automation.”

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Categories / Science, Technology

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