On an early April morning, around 4 am, a San Francisco Fire Department truck responding to a fire tried to pass a doubled-parked garbage truck by using the opposing lane. But a traveling autonomous vehicle, operated by the General Motors subsidiary Cruise without anyone inside, was blocking its path. While a human might have reversed to clear the lane, the Cruise car stayed put. The fire truck only passed the blockage when the garbage truck driver ran from their work to move their vehicle.

“This incident slowed SFFD response to a fire that resulted in property damage and personal injuries,” city officials wrote in a filing submitted to the California Public Utilities Commission. The city wrote that the fire department is concerned that Cruise vehicles stop too often in travel lanes, which could have a “negative impact” on fire department response times.

It’s the most unnerving of a handful of incidents involving Cruise vehicles alleged by the city of San Francisco, as officials object to parts of a proposed permit program being crafted by the California Public Utilities Commission, which regulates ride-hail across the state.

Tiffany Testo, a spokesperson for Cruise, confirmed the incident. She said the driverless car had correctly yielded to the oncoming fire truck in the opposing lane and contacted the company’s remote assistance