Johnson also said Waymo’s vehicles are getting better at dealing with pedestrians.
In an October video, a Waymo car was driving through a Costco parking lot crowded with pedestrians. It waited patiently until they were out of the way, then moved forward confidently.
“This amount of pedestrians would have caused whiplash-inducing brake usage in March 2020,” Johnson wrote in an on-screen note. “And it would have completely given up in July 2019. No longer!”
The vehicles are still a little too cautious around pedestrians. In one recent video, Johnson called a Waymo vehicle to a crowded retail parking lot, hit “start ride,” and then had to wait almost 3 minutes before the vehicle moved a significant distance. There were apparently so many pedestrians and other vehicles around that the Waymo car didn’t feel safe moving forward.
A human driver almost certainly would have moved sooner. But it’s hard to blame Waymo for this—far better to be a little slow than to risk running someone over.
Of course, four hours of perfect driving—or 40 or 400 hours for that matter—wouldn’t be enough to prove that Waymo’s cars are safe. To properly evaluate the safety of Waymo’s vehicles requires a lot of data. And Waymo has more than 20 million miles of real-world driving data. Almost all of that mileage is on public roads with a safety driver behind the wheel. A small fraction—65,000 miles through September 2020—were fully driverless.
Until recently, Waymo kept this data private, making it difficult for the public to evaluate the technology. In October, Waymo took a big step toward greater transparency by releasing data about the real-world performance of its vehicles. It covered 6.1 million miles the company logged in the Phoenix metro area in 2019 with a safety driver behind the wheel—plus 65,000 miles of driverless operation from the start of 2019 through September 2020.
In 6 million miles of driving, Waymo’s vehicles were involved in 18 crashes. Of course, for most of those miles, the vehicles had safety drivers who were supposed to intervene in case of an imminent crash. To estimate how well the cars would have performed without a safety driver, Waymo performed simulations of every situation where a safety driver took control. These simulations predicted that another 29 crashes would have occurred if the safety drivers hadn’t intervened.
While 47 crashes might seem like a lot, it’s important to remember the denominator. Waymo’s vehicles got into a crash—or likely would have gotten into a crash without human intervention—once every 130,000 miles or so. That’s equivalent to more than 10 years of driving for a typical human being who drives 1,000 miles per month.
It’s surprisingly difficult to figure out what the comparable rate would be for a typical human driver. Some of the 47 collisions Waymo reported were extremely minor. For example, a pedestrian walked into the side of a stationary Waymo vehicle at 2.7 miles per hour. Two simulated crashes involved a bike and a skate boarder rolling into the sides of stationary Waymo vehicles at speeds of 2.2 and 5.9 miles per hour, respectively.
Such minor low-speed collisions would never be reported to the police or other authorities, so we don’t know how many “crashes” like this a typical human driver experiences.
More important, most of those 47 incidents appeared to be the fault of another driver. For example, a third of real and simulated crashes were rear-ending incidents. All but one of these—14 actual collisions and one simulated crash—involved another vehicle rear-ending a Waymo car. The final rear-ending was a simulated crash where the Waymo car would have rear-ended another vehicle at a speed of 1 mph.