An Uber self-driving car collided with another vehicle in Pittsburgh on February 24 in an incident first reported by Pittsburgh's channel 11 last week. No one was seriously injured, but the incident caused serious damage to the vehicles. Uber and the other driver disagree on exactly what happened in the seconds before the crash, and it's not clear if the Uber vehicle did anything wrong.

The driver of the other car was Jessica McLemore, a mother of three children. She described the incident in a Wednesday interview with Ars Technica.

The crash occurred in Pittsburgh's Strip District. McLemore was on a four-lane road called Liberty Avenue, heading Northeast, while the Uber vehicle was approaching from the opposite direction. This screenshot from Google Maps shows the intersection.

"There was no other oncoming traffic," McLemore told Ars. "I had my turn signal on to make the left and he had his right turn signal on."

"As I was making my left, he continued to drive straight and slammed directly into the side of my vehicle," she said.

After the crash, McLemore confronted the safety driver of the Uber vehicle, capturing the conversation in a video she posted to Facebook. The Uber driver acknowledged that the self-driving system had been in control at the time of the crash, and he acknowledged that both cars had turn signals on.

"I was not expecting someone to turn from the far left lane into my lane," the Uber safety driver said.

Uber declined to comment on the record about the incident, but the company did dispute an important detail in the story: Uber says that the Uber vehicle had its left turn signal on. That's because, according to Uber, the car was preparing to change lanes.

We called Matthew Becker, a Pennsylvania attorney who works on traffic cases. He said he couldn't say who was liable in the case without knowing more details. But he did tell us that "generally speaking, before you take a left-hand turn, you're required to ensure there's not traffic coming from the other direction."

McLemore says that she hasn't heard back from Uber since the crash. "I have not been able to get in touch with anybody," she told Ars. "I've got no answer regarding damage to my vehicle, if they're going to pay for the damage."

Crashes involving driverless cars have gotten more common as Uber, Waymo, GM, and other companies have ramped up their testing efforts. In the vast majority of cases, companies have argued that the other car is at fault, and there are few if any cases where authorities found a driverless car company legally liable for a crash. But in some cases, critics have argued that erratic driving by the driverless car contributed to the accident.

For example, late last year, a self-driving car from GM's Cruise collided with a motorcycle in San Francisco. The Cruise car had tried to change lanes, then abruptly aborted the lane change when the space to make the change disappeared. Unfortunately, a motorcycle had pulled up next to the Cruise car in the meantime, and the Cruise vehicle sideswiped the motorcycle.

Cruise argued that the motorcycle was at fault, since it shouldn't have pulled up beside the car until the lane change was complete. But the motorcyclist sued, arguing that the car's unpredictable driving was responsible for the accident.