Traffic
How safe are autonomous vehicles?
According to a study, autonomous vehicles are safer than human drivers – mostly. Photo
© Christian Charisius/dpa
Autonomous vehicles have become safer, a study shows. But in certain situations, humans drive much more safely.
Mohamed Abdel-Aty and Shengxuan Ding from the University of Central Florida in Orlando evaluated the circumstances of more than 37,000 accidents. 2,100 of these involved highly or partially automated vehicles – with partially automated cars, someone always has to sit behind the wheel and control the assistance systems.
Although there has been progress in terms of safety with autonomous vehicles, the study authors write, the exact differences between autonomous and human-driven vehicles in terms of accident risk are largely unclear because there is still little accident data on autonomous vehicles.
The researchers collected information on accidents involving autonomous vehicles from several American databases and compared them with more than 35,000 accidents involving vehicles with human drivers. A good 15 percent of accidents involving human drivers involved pedestrians, while the figure for autonomous vehicles was only 3 percent. In almost 20 percent of accidents involving people, inattention or poor driving behavior was evident beforehand.
People cause more rear-end collisions
On the other hand, 5.5 percent of accidents involving autonomous vehicles occurred in construction zones or in connection with specific incidents, such as accidents involving other road users. For human drivers, this rate was just over 1 percent. In rear-end collisions, 79 percent were caused by vehicles driven by humans. And when autonomous vehicles were the cause, in almost three quarters of the cases (72 percent) they were not driving in automated mode – so a human was responsible.
“We can conclude that compared to autonomous mode, human drivers may not react as quickly or may not notice the object in time to react accordingly,” note Abdel-Aty and Ding.
In a special analysis, the researchers also took into account traffic volume, weather, road surface, location and other characteristics of the accidents. From this they made predictions about the probability of accidents in certain situations.
According to the study, the probability of an accident in rain for a highly automated vehicle is only around a third of that of a vehicle driven by a human. The scientists explain this, among other things, by the fact that radar sensors enable autonomous vehicles to see up to 150 meters, while humans may have to make do with a tenth of the visibility.
Turning and twilight are problematic
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 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.”