Revelers celebrating US independence day in San Francisco over the weekend were stopped in their tracks as an untold number of Waymo robotaxis stalled, exacerbating the city’s horrible holiday gridlock.

According to NBC News, several Waymos had to be towed out of busy roadways after their batteries died on one of the city’s worst traffic days of the year so far. On top of intense fog and significant public transit slowdowns, travelers had to bob and weave past the bricked electric vehicles, which in some cases blocked traffic completely.

One resident, Dave Guingona, told NBC he spent two hours sitting in traffic waiting for a “number of Waymo vehicles” to be towed away.

“Five minutes, 10 minutes, 15 minutes went by, then we realized people were getting out of their cars, yelling and screaming at these Waymos because there were no drivers,” Guingona said.

Another video viewed by NBC showed Waymos parked in the middle of a busy intersection, one of which was being hauled off on a flatbed truck.

In one case, resident and Waymo rider Rose Peterson said her vehicle drove straight over lit fireworks that someone had set off in the crosswalk — a pretty typical scenario for US cities on the Fourth of July, but evidently an edge case in training data for autonomous vehicles.

“We were pulling up to a four-way stop and this guy was shooting off a firework in the middle of the road, and then our Waymo starts driving, and we’re like ‘wait, what’s happening?” Peterson said. “I definitely think it needs to be more sensitive of anything that can come into the path of the road.”

The city-wide autono-mess comes not even a year after a blackout in the Bay Area left Waymos stranded in the streets, putting a massive strain on public resources, much like did on the Fourth. It just goes to show: you can take the human out of the driver’s seat, but at the end of the day, a car’s gonna do what a car’s gonna do.

More on Waymo: Waymo Caught Driving Straight Into Oncoming Traffic