A vehicle that can drive itself? Until recently, it was the stuff of science fiction. Google and Tesla have been developing autonomous vehicles with an eye toward a safer, driverless future. But there have been some accidents, including one fatal collision earlier this year.

So when will these cars be safe enough for us to own and drive?

A Fatal Accident In Florida

Google has been testing its driverless cars on the streets of Silicon Valley for several years, largely without incident. On September 26, 2016, one of Google’s self-driving vehicles, a Lexus sedan, was struck by a vehicle that ran a hard red light in Mountain View, California. PC Magazine reported that the “driver” was not hurt, and that the Google car was not at fault.

According to the New York Times, an Ohio man, 40-year-old Joshua D. Brown, was killed in May 2016 in Williston, Florida, when his electric Tesla Model S was struck by a truck making a left turn. Apparently, the self-driving Tesla failed to brake because the car was unable to sense the white truck against a bright sky. Brown is thought to be the first fatality in a string of mostly minor accidents involving self-driving vehicles.

So When Will These Vehicle Be Ready?

While there is no way to eliminate negligent drivers from the road, consumers want to feel very secure about autonomous vehicles before they purchase one, especially if they are more expensive than human-driven vehicles. An autopilot-ready Tesla, for example, will set you back at least $70,000.

Numerous car manufacturers have released or are close to releasing autonomous or semi-autonomous vehicles. By some estimates, we will see millions of cars with self-driving capabilities by the end of the decade. For now, most of us will watch and wait.