The move comes as concerns have been raised over the safety of driverless vehicles.
Earlier this year a woman was hit and killed by a driverless car owned by ridesharing company Uber.
Elaine Herzberg, 49, was crossing a road in the city of Tempe when she was hit by the car, which was in self-driving mode but had a human safety driver behind the wheel at the time. She died of her injuries later in hospital.
A driverless shuttle bus was also involved in a crash less than two hours after it was launched in Las Vegas.
But police confirmed the lorry driver who reversed into the electric vehicle was responsible for the crash in November last year.
It has been long debated whether self-driving vehicles should attempt to save the passengers inside or other pedestrians involved when a crash occurs.
Stagecoach announced in July that it was to trial the UK’s first driverless buses. Though laws currently restrict the use of driverless cars on UK roads, the transport giant has made the move in the hope that legislation will be adapted as technology improves.