Almost since cars have had back seats, motorists have been plagued by the hectoring advice of back seat drivers.

But soon car drivers could be praising rather than cursing those nagging voices as IBM scientists develop an artificial passenger to help drowsy drivers stay awake and on the road.

The artificial passenger can analyse speech for signs of sleepiness and is programmed to ask startling questions to provoke drivers in wakefulness.

If all else fails the dashboard will squirt cold water into the face of a driver to keep them concentrating on the road ahead.

Sleep signs

New Scientist reports that Wlodek Zadrozny and Dimitri Kanevsky at IBM's Thomas J Watson lab in New York are creating the software surrogate that will lurk in a modified dashboard monitoring what a driver is doing.

Drivers that nod off while at the wheel are thought to be responsible for causing up to 30% of road traffic accidents in the UK, according to figures from the Transport Research Laboratory in Crowthorne, Berkshire, quoted by New Scientist magazine.

The artificial passenger will work out if a driver is in danger of falling asleep by initiating conversations and monitoring responses. The conversational cues are created by consulting a profile of a drivers likes and dislikes stored by the smart software.

Responses to provocative questions by the artificial passenger are analysed to see if your response is slow or the intonation of the speech is slurred, perhaps reflecting how fatigued a driver has become.

Telling jokes

As well as listening to responses, the passenger uses a camera to watch the mouth of a driver and fine tune its speech recognition system.

If a response indicates a driver is getting sleepy, the artificial passenger has several options available to rouse the person behind the wheel. It could wind down a window to let cold air circulate, sound a buzzer and perhaps even use a spray to dash cold water into the face of the driver.

Other possible actions include changing radio station, or telling jokes in a bid to jerk a drowsing driver into wakefulness.

The two scientists are reportedly talking to car makers about adopting the artificial passenger. "If this is something people want, it's doable within three to five years," Dr Zadrozny told New Scientist.