Google will likely shed full detail on the collision in its self-driving car report due at the end of the month. It makes no bones about what happened in a statement, though (see below). The Lexus didn't enter the intersection until "at least" 6 seconds after its traffic light turned green. There was no question that the van driver was at fault, in other words. Google also stressed that red light violations are the "leading cause" of car crashes in US cities, and that 94 percent of those are due to human mistakes.

Although the outcome could have been much worse, the crash underscores a key problem with moving to autonomous cars: that piloted and robotic vehicles will likely have to share the roads for a long while. Google, Uber and others can design driverless systems that follow the law to a tee and adapt swiftly to unexpected road hazards, but it might be near-impossible to protect against human drivers who throw caution to the wind. Crashes like these likely won't disappear unless self-driving tech becomes the rule.