A little more than a month ago, to start charging passengers for rides in its autonomous, driverless robotaxis. It was a major milestone for the service. A day later, on June 3, one of those robotaxis was involved in a crash in San Francisco, where occupants in both vehicles suffered minor injuries, per a California DMV report surfaced by .

That crash is likely now the subject of a special investigation by the National Highway Traffic Safety Administration (NHTSA), the government department .

The DMV report contains Cruise’s own testimony of what transpired, and it places the blame pretty solidly on the human driver. According to the company, the taxi was attempting a left turn in front of an oncoming Toyota Prius on the intersection of Geary Boulevard and Spruce Street when the two collided. The Prius was in the rightmost turning lane but traveled straight through the intersection while speeding and, at some point before the crash — it’s not exactly clear when — the Cruise vehicle stopped. From Cruise’s filed :

As it approached the intersection, the Cruise AV entered the left hand turn lane, turned the left turn signal on, and initiated a left turn on a green light onto Spruce Street. At the same time, a Toyota Prius traveling westbound in the rightmost bus and turn lane of Geary Boulevard approached the intersection in the right turn lane. The Toyota Prius was traveling approximately 40 mph in a 25 mph speed zone. The Cruise AV came to a stop before fully completing its turn onto Spruce Street due to the oncoming Toyota Prius, and the Toyota Prius entered the intersection traveling straight from the turn lane instead of turning. Shortly thereafter, the Toyota Prius made contact with the rear passenger side of the Cruise AV.

Cruise stated that “occupants of both vehicles received medical treatment for allegedly minor injuries.” It’s important to note that we’re working with only one side of the story here; according to Automotive News, the San Francisco Police Department did not generate its own incident report on the matter, and Cruise’s interpretation of the events could not be independently verified. Cruise communications director Drew Pusateri confirmed to Jalopnik that the company’s vehicle was not issued a citation.

Context is everything, and there’s still so much we don’t know. Reading Cruise’s statement, it’s easy to leap to the conclusion that the Prius driver disregarded the intersection’s traffic patterns. Perhaps the Cruise AV expected the Prius to turn right as it completed its own left turn, but instead, the Prius continued straight and clipped the back right of the robotaxi.

It’s also entirely possible the Prius driver had every intention to turn right but swerved left to avoid the robotaxi, because they couldn’t anticipate its movements — a scenario that Carnegie Mellon’s Phil Koopman, quoted in Automotive News’ story, raises:

Although the Cruise vehicle may have been stationary, Phil Koopman, a Carnegie Mellon University professor and autonomous-vehicle safety expert, said much more information would still be needed to assess the behavior of both humans and machine in the crash.

“Many people have a word for a driver who cuts in front of them and then stops in the road, and it’s not a polite or charitable word,” he said. “There are a lot of unknowns here. We don’t know if the Prius driver intended to turn right, but then swerved to try and avoid the crash with the stationary vehicle, for example. There are just a lot of unknowns.”

GM hasn’t confirmed the number of occupants in the Cruise vehicle, nor whether airbags deployed inside the cabin. It’s important to note that the NHTSA’s special crash investigations are not the same as the defect probes it also conducts that sometimes lead to recalls.

The department told on Thursday that it “has had conversions with Cruise officials regarding the incident.” The NHTSA hasn’t specifically said which incident it’s probing, as Cruise cars were involved in 23 crashes between June 2021 and May 2022 per the administration’s . However, the timing would indicate that this was the one that prompted the investigation.

Several weeks after this crash, , right off Gough. A Cruise spokesperson termed this a “” whereupon the vehicles “clustered together,” and reportedly had to be removed by company personnel.

This story was updated following news that the NHTSA had launched its own special investigation into a crash involving a Cruise self-driving taxi. It was also updated with new detail about the June 3 incident provided to Jalopnik by Cruise personnel.