STUTTGART, Germany — Mercedes-Benz on Monday said it will roll out its new Attention Assist, which warns drivers that they are getting drowsy, on vehicles in spring 2009.

The system, in some ways, is an example of the ultimate in vehicle customization.

Mercedes-Benz said that the system, using sensors and computer data, is able to generate 'an individual driver profile,' thus enabling it to almost immediately recognize the driver's shift from alertness to drowsiness. The system compiles data on your driving pattern the moment you slide behind the wheel and can adjust to a variety of drivers almost instantly.

If the vehicle recognizes that the driver is slipping toward what the German automaker calls the 'dangerous one-second nap,' it sounds an acoustic signal and lights up a display in the instrument panel. The system literally tells the driver, 'Attention Assist. Brake!'

Mercedes-Benz said the system not only takes into account vehicle speed and linear/lateral acceleration, it also tracks steering wheel movements, indicator and pedal operation and uneven road surfaces. 'An overtired driver has difficulty in keeping the vehicle precisely on track,' the company points out.

'He makes minor steering errors which are often quickly corrected in a characteristic manner,' Mercedes-Benz said. 'Intensive tests by Mercedes engineers involving more than 550 male and female drivers have shown that this effect already commences during an early phase of the onset of fatigue — usually before the highly dangerous 'one-second nap.' '

No word yet on how much the system will add to the price of a new vehicle.