Volvo is launching a breathalyser system that will stop drunk drivers from starting their cars, and you’ll be able to get it from early in 2008.The system, dubbed Alcoguard, consists of a wireless hand-held breathalyser unit, similar to that used by police forces, which links to the car’s engine management.Before the car can be started, the driver must blow into the unit; if the blood-alcohol limit is exceeded, the engine will not start.As standard, the unit is set for the Swedish limit of 20mg of alcohol per 100ml of blood, but it can be adjusted for the UK limit of 80mg.If the driver’s alcohol level is below 10mg, then the car starts; if it’s up to 20mg it starts but advises the driver not to drive. Any more, and it won’t start.Volvo says that the system cannot be cheated by using air pumps or the like, though there’s nothing to stop a sober passenger from blowing into the unit. Then again, if we were sober, we wouldn’t really want a drunk driver.There’s also an optional emergency override in case, for example, the Alcoguard unit breaks. This can be set by the dealer for either a one-off bypass, or unlimited, which to our minds nullifies the point of the system.The Alcoguard system will initially be available on the S80, V70 and XC70; the rest of the line-up will get it in due course. Volvo reckons that it will sell around 2000 units a year globally, with company cars being a large potential market. A price has yet to be decided on.