The next level of driverless cars: how to solve the problem of humans falling asleep

Next wave of development will see drivers only expected to intervene when the car requests it, say researchers

Driving down the motorway in a swanky semi-autonomous car, the vehicle is at its own wheel, humming along smoothly. But coming off a slip road it is over to you. The only trouble is, you've fallen asleep.

The goal of a completely driverless car is considered top of a six-level scale of autonomy, and researchers believe it will one day be possible to achieve that aim. But for now, cars are stuck at level two on the scale - in which the driver must still perform several key aspects of driving - while engineers work out how to crack the problem of keeping drivers alert.