Self-driving cars have been praised as preventing road accidents, and they could significantly reduce them by reducing the chance of human error. However, 8 percent of autonomous cars on California roads have been involved in collisions since September.
California started issuing permits for driverless cars in September 2014. Since then, four of around 50 such vehicles have been in self-driving car crashes.
Three of the vehicles in the accidents were self-driving Lexus SUVs, which are part of the Google autonomous car program. The other Audi vehicle is produced by Delphi, another unmanned car manufacturer, according to Gizmodo.
Two of the self-driving car accidents occurred while the vehicles were in control. In the other two autonomous car accidents, the driver sitting behind the steering wheel was operating the vehicle.
The United States' rate of crashes only resulting in property damage is around 0.3 per 100,000 miles (160,930 km) driven. Within that context, the three in around 140,000 miles (225,300 km) of the Google self-driving car is fairly high.
None of the accidents of the autonomous cars were major, and tweaks are expected when automated cars are being tested. Google has also noted to reporters that a comparison with the official U.S. auto accident figures is unfair, considering that minor car accidents are often unreported.
Chris Urmson, project manager of Google's self-driving car project, also reported that the company's six-year project has logged 1.7 million miles (2.7 million km). At that time, 11 accidents happened and none were the fault of the self-driving car, according to Slate.
While self-driving vehicles offer much potential, the accident rate is still quite high. It also highlights that self-driving car technology is not yet a perfectly smooth ride.