ORLANDO (dpa-AFX) - According to an analysis, autonomous vehicles have a lower accident risk in most situations than those driven by humans. But there are exceptions: Accidents involving an automated vehicle are significantly more likely at dusk and when turning, US researchers write in the journal "Nature Communications".

Mohamed Abdel-Aty and Shengxuan Ding from the University of Central Florida in Orlando analyzed the circumstances of more than 37,000 accidents. Highly or semi-automated vehicles were involved in 2100 of these - in semi-automated cars, someone always has to sit behind the wheel and control the assistance systems.

The authors of the study write that progress has been made with autonomous vehicles in terms of safety. However, the exact differences between autonomous and human-driven vehicles in terms of accident risk are largely unclear because there is little accident data on autonomous vehicles.

The researchers have now compiled data on accidents involving autonomous vehicles from several American databases and compared it with more than 35,000 accidents involving vehicles with human drivers. A good 15 percent of accidents involving human drivers involved pedestrians, compared to just 3 percent of accidents involving autonomous vehicles. In almost 20 percent of accidents involving human drivers, inattention or poor driving behavior was evident beforehand.

On the other hand, 5.5 percent of accidents involving autonomous vehicles occurred in roadworks or in connection with special incidents, such as accidents involving other road users. For human drivers, this rate was only just over 1 percent. In the case of rear-end collisions, 79 percent were caused by human-driven vehicles. And when autonomous vehicles were the cause, in almost three quarters of cases (72 percent) they were not driving in automated mode - in other words, a human was responsible.

"We can conclude from this that human drivers may not react as quickly or notice the object in time to react appropriately compared to autonomous mode," Abdel-Aty and Ding note.

In a special analysis, the researchers also took into account the traffic load, the weather, the roadway, the location of the incident and other characteristics of the accidents. From this, they drew up predictions for the probability of accidents in certain situations.

According to the results, the probability of a highly automated vehicle having an accident in the rain is only around a third of that of a human-driven vehicle. The scientists explain this in part by the fact that radar sensors enable autonomous vehicles to see up to 150 meters ahead, while humans may have to make do with a tenth of the visibility.

However, there is a noticeably higher risk of accidents with autonomous vehicles in difficult visibility conditions at dusk and when turning. At dusk, the probability of an accident is more than five times higher, and when turning off, it is still twice as high as with a vehicle driven by a human.

Overall, the researchers assess the accident risk posed by autonomous vehicles positively: "Based on the results of the model estimation, it can be concluded that highly automated driving systems are safer than human-driven vehicles in most scenarios due to their object detection and avoidance, precise control and better decision-making."/fm/DP/mis