A car that can tell when a drink-driver gets behind the wheel - and stop him or her moving off - has been developed by Nissan.
It uses a combination of electronic 'noses' to sniff the air and cameras and behavioural detectors to decide if a driver is inebriated. If the answer is yes, the car is immobilised.
The system can even differentiate between the driver's breath and that of passengers who may have had a drink.
Some cars are already being fitted with 'alco-locks', which require the driver to blow into a tube to give a breath sample before they are allowed to start off. But the Nissan technology is different because it does not need any action by the driver.
Instead, motorists are monitored from the moment they get behind the wheel. An alcohol odour sensor checks the breath while another tests for alcohol in the sweat of a palm touching the gear stick.
A tiny dashboard-mounted camera monitors the driver's face and eye movements and detects whether they are fit to drive. It measures the rate of blinking - an indicator of drowsiness - and examines features such as the droopiness of the mouth to check for yawning.
When the detected alcohol level is above a preset threshold - which can be at or below the legal limit - the system locks the transmission, immobilising the car. A ‘drink-driving’ voice alert is sounded via the car's satellite navigation system.