It’s SF driving 101 that you should not follow a confused self-driving Waymo vehicle down a closed road, but that’s what happened Tuesday night near Highway 101 in Potrero Hill, after a stalled Waymo traffic jam led to the robotaxis veering into a closed lane.

It was back on March 1 that Google’s self-driving car division Waymo got permission to drive on freeways in California. So you figured it was only a matter of time until there was some sort of self-driving car freeway snafu.  That sort of happened Tuesday night, not directly on US Route 101, but some 300 feet from it. TechCrunch reports that six Waymos blocked traffic near the 101 on-ramp, and then pulled onto a closed road to get out of the mess.  

The video below is clearly on Potrero Avenue, and is apparently from about 9:30 pm Tuesday night.

Line of driverless Waymos glitch out and block the Portrero Avenue 101 onramp
byu/dzdaniel84 insanfrancisco

“I was driving back home just now when the traffic came to a sudden stop on the 101 onramp,” a Reddit poster says. “After sitting in the car waiting for several minutes, a couple of people came out and started moving traffic cones and a construction sign to allow traffic to pass through. I'm not sure how much traffic passed through, since there was a Muni bus right behind me that couldn't take this detour, but it was a pretty shitty situation all around. I guess autonomous vehicles still aren't fully there yet.”

People moving construction cones to allow traffic to bypass a line of stalled driverless Waymos in San Francisco

There is additional video of human drivers getting out of their cars to move orange traffic cones so they can maneuver out of the stalled-Waymo jam.

While Waymo has permission for its self-driving cars to operate on US 101, they say they are still only allowing human drivers on that highway. And that restriction may have been what caused the clusterfudge, as apparently one of the Waymos had a human driver at the wheel.

The SF Standard got a statement out of Waymo over the incident. "The Waymo driver pulled over to a safe location, out of the traffic lane, in an area blocked by cones," a Waymo spokesperson told them. "Other vehicles, both human and autonomously driven, followed the Waymo vehicle into the road closure."

Waymo said it dispatched Roadside Assistance and cleared the situation up within about 30 minutes.

These are fairly vague explanations  of what actually happened and why. But it appears that Waymos got confused and stalled, human divers intervened and moved the cones, which led to different behavior by the Waymos. So one thing the robot cars may not have figured out yet is how to respond when human drivers take matters into their own hands.

Related: Waymo Gets State Approval for Los Angeles and SF Peninsula Expansion — and Freeway Driving [SFist]

Image: dzdaniel84 via Reddit