Uber on Thursday rolled out its self-driving car prototypes on public roads for the first time since the March accident where one of the prototypes hit and killed a woman, Elaine Herzberg, pushing a bicycle across a stretch of road in Tempe, Arizona.

The prototypes are currently testing near Uber's development center in Pittsburgh, Pennsylvania, after the company received a letter from the state's Department of Transportation allowing it to drive its prototypes on public roads, albeit with major restrictions.

Uber is also preparing to test its prototypes in San Francisco and Toronto. The prototypes are being manually driven in those cities to gather data ahead of the start of self-driving tests. The company has been banned from testing vehicles in the state of Arizona, however.

The prototypes in Pittsburgh are limited to a one-mile course with a posted speed limit of 25 mph. At least two safety drivers are required on board at all times, and the donor vehicles' safety systems, such as automatic emergency braking, also must be left on. Uber uses Volvo XC90 SUVs as the donors for its prototypes, but in previous tests the original Volvo safety systems were switched off to prevent them from interfering with Uber's self-driving system.

A National Transportation Safety Bureau report published in May confirmed Uber's system "saw" Herzberg roughly 6 seconds before the crash or more than 350 feet away from the vehicle, which was traveling at 43 mph. The system first determined that Herzberg was an unknown object, then a vehicle, then a bicycle with varying travel paths.

According to the report, Uber's system determined that 1.3 seconds before the crash that an emergency maneuver would be necessary, but it did not have a warning for the safety driver, Rafaela Vasquez. A video showing Vasquez in the moments before the crash showed her looking down and away from the road frequently. It was later determined that she was streaming a show on her phone.

Uber is well behind the competition when it comes to self-driving cars, and the March accident is likely to leave some of the public distrustful of the company's system, if it's actually ever offered. Meanwhile, Alphabet Inc.'s self-driving unit Waymo is already offering rides in a limited service in Phoenix, Arizona, and auto giants General Motors and Daimler have both confirmed plans to start their own limited self-driving services next year.