Drivers who choose to buy a Nissan self-driving car in the future may find it ultra-cautious, early trials suggest.
Motoring journalists who took a spin in a zero-emissions Nissan Leaf fitted with the autonomous tech compared it to a grandmother's driving.
The Japanese carmaker unveiled the "intelligent driving" concept car to the public at the Tokyo Motor Show. It hopes to put such vehicles in showrooms by the start of the next decade, but admits more work is first needed.
Reporters were able to test-drive the tech, which relies on computer chips, radars, cameras and lasers. But human intervention is still needed at what Nissan admits is an early stage for the prototype car.
Its human driver, Tetsuya Iijima, who sat behind the wheel for the entire ride, had to take over because the vehicle did not totally recognise a lane.
The new tech is clever enough to negotiate junctions with no lane markers, however. It can also differentiate between tail-lamps and red lights and brake safely without bumping into the car in front.
The tech still cannot cope with unforeseen scenarios, including pulling over in the event of an ambulance approaching.
Journalists who participated in the 30-minute test ride on the pre-programmed Tokyo road route describe the car as being like an "extra-cautious", "painstakingly careful" driver.
The car never strayed from the speed limit, while reporters also noticed that it slowed down when faced with difficult situations, including cars transferring from a different lane.
Mr Iijima, who is also Nissan's general manager, says he remains optimistic that the tech can offer improved safety in the future. This is because human error is behind more than nine in 10 road accidents, he says. But Mr Iijima added that more work is still needed.
Copyright Press Association 2015