As San Francisco city leaders continue to assess what went wrong on the night of July 4th to create such a traffic mess around the Marina and Presidio, a letter from Uber points to a few key obstructions caused by — you guessed it — Waymo.

There were, of course, a number of factors that contributed to the royal, semiquincentennial clusterfuck of July 4th, when more people than expected flooded into San Francisco, many in their own cars, to see what promised to be a lackluster and socked-in fireworks display on the Golden Gate Bridge. And one of them was the sheer volume of cars, compounded by the many people traveling from other parts of the city or from BART downtown via rideshares and Waymos.

Uber, which has of course been competing with robotaxi outfit Waymo in recent years, sent off an email to the SF Board of Supervisors laying the blame on Waymo for obstructing a few key roads, leading to gridlock, as the Chronicle reports.

"I think it’s important to note that when there is limited ingress and egress, a few road obstructions can impact the entire transportation network," wrote Danielle Lam, head of local California policy for Uber, in an email obtained by the Chronicle.

Lam calls July 4th an "outlier," and says by Uber's metrics, as of 9 pm on the 4th, 66% of its drivers were going 10 miles per hour or slower through the Presidio, which is the company's threshold for gridlock. Lam reportedly told the supervisors that this was twice as bad as on the Saturday of Fleet Week last year, October 11, when traffic was also heavy in the same area for the air show.

The Chronicle points out a long line of stalled Waymos that blocked a key connector in the Presidio, Edie Road, which connects to the Girard Road roundabout, which was well documented on social media — and despite what everyone has said in SFist comments about EVs not running out of battery easily, Waymo has confirmed to the Chronicle and to KQED that, yes, some Waymos ran out of battery in traffic that night and had to be towed. The company has not said how many vehicles that happened to.

Supervisor Rafael Mandelman, who is also president of the Board, is pushing state regulators to potentially enact rules that would ban Waymos from city streets altogether during major events. Still, Mandelman tells the Chronicle, stalled Waymos were only one part of the "stew of bad things that led to a bad night."

Waymo has said in a statement that it will "apply any learnings to our operations to strengthen Waymo’s resilience during major traffic disruptions in the future."

Previously: SFMTA Apologizes as Supervisors Call For Hearing Into July 4th Traffic and Transit Fiasco

Photo via TheDamianHdez/X