Uber began its self-driving car pilot programme last month
A witness reported one car going the wrong way down a one-way street
Another person saw a car being pulled over having been in an accident The cars take passengers to their destination without the aid of a driver, although a driver is always present in case of an emergency
Last month, Uber began a self-driving car pilot project, taking passengers around Pittsburgh in autonomous mode.
But it appears that the programme may have got off to a bumpy start, with reports of multiple problems.
Witnesses have revealed that the self-driving Uber cars have been involved in accidents and disobeyed traffic signs in the two weeks since the pilot launched.
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Nathan Stachelek, an Uber driver, reported seeing a self-driving car turn down a one-way street before its operator had to take control and turn the car back around
HOW DO THE TESTS WORK?
Uber is now testing autonomous vehicles around Pittsburgh, Pennsylvania. A hybrid Ford Fusion with the Uber logo is being used for mapping data of Steel City and testing its self-driving capabilities on public streets.
The cars are equipped with a variety of sensor, radars and high-resolution cameras.
While the car is roaming around Pittsburgh, a trained driver will be seated in the driver's seat to monitor the vehicles performance - but the car will be set in self-driving mode.
Uber is currently testing a fleet of self-driving Ford Fusions in Pittsburgh for the first time.
The cars are in self-driving mode, but have a driver in place who can step in if needs be.
Mr Stachelek was unsure whether the error was due to the human driver or the car itself, but posted a video of the event on his Facebook page.
According to Quartz, another Uber driver - who asked to only be referred to as Jason - also witnessed a self-driving Uber being pulled over, having been in an accident.