Self-driving cars may not be safer than human drivers. Here's why

Their respective crash rates can only be determined by also knowing how many non-collisions happen

Much of the push toward self-driving cars has been underwritten by the hope that they will save lives by getting involved in fewer crashes with fewer injuries and deaths than human-driven cars. But so far, most comparisons between human drivers and automated vehicles have been at best uneven, and at worst, unfair.

The statistics measuring how many crashes occur are hard to argue with: More than 90 percent of car crashes in the US are thought to involve some form of driver error. Eliminating this error