Google revealed that one of its self-driving cars was, for the first time, involved in an injury accident on July 1, 2015. A Google self-driving Lexus SUV was rear-ended in Mountain View, Calif., and the three Google employees on board complained of minor whiplash.

The Google employees were later released by a local hospital, and the driver of the other car also complained of neck and back pain.

Google’s SUV had slight damage to its rear bumper, while the vehicle that struck it lost its front bumper.

Here’s how the accident went down, according to an accident report Google filed with the California Department of Motor Vehicles:

“Google’s SUV was going about 15 mph in self-driving mode behind two other cars as the group approached an intersection with a green light. The first car slowed to a stop so as not to block the intersection – traffic on the far side was not moving. The Google car and the other car in front of it also stopped. Within about a second, a fourth vehicle rear-ended the Google car at about 17 mph. On-board sensors showed the other car did not brake.”

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Chris Urmson, head of Google’s self-driving car program, revealed details about the accident in a recent blog, writing that Google’s self-driving SUVs “are being hit surprisingly often by other drivers who are distracted and not paying attention to the road.”

Urmson even posted a video (watch it below) that allegedly shows how Google’s self-driving car was tracking other vehicles at the time of the crash, including the one that hit it. As you can see from the video, Google’s braking appears normal, and the vehicle behind us had plenty of stopping distance,? ?but it never decelerated.

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This certainly seems like the driver was distracted and not watching the road ahead. Here’s more from Urmson:

The clear theme is human error and inattention. We’ll take all this as a signal that we’re starting to compare favorably with human drivers.

Our self-driving cars can pay attention to hundreds of objects at once, 360 degrees in all directions, and they never get tired, irritable or distracted. People, on the other hand, ‘drive as if the world is a television show viewed on TiVo that can be paused in real time? – ?one can duck out for a moment, grab a beer from the fridge, and come back to right where they left off without missing a beat’ – ?to quote Sheila Klauer of the Virginia Tech Transportation Institute in Traffic: Why We Drive the Way We Do.

That’s certainly consistent with what we’re seeing. Please, as you get behind the wheel this summer, keep your eyes on the road. The fight to end distracted driving starts with each of us? – at least until that day when you can summon a self-driving car and just kick back, relax, and enjoy the ride.

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This was the 14th accident in six years and about 1.9 million miles of testing, according to Google, which has said its cars have not caused any of the collisions. In 11 of the 14, Google said its car was rear-ended.