While alert systems from Ford, Mercedes, Volvo, and Volkswagen monitor external vehicle behavior like swerving to determine a driver's level of drowsiness, Denso's new prototype is much more up-close and personal — using a camera mounted on the steering column, it analyzes 17 feature points from the driver's face to see if they're about to take a nap behind the wheel. Custom software tracks muscle movements to calculate the driver's alertness on a scale of one to six, and the system can advise the driver at early levels of tiredness to prevent accidents. The tech is currently being demonstrated at the 2011 Tokyo Motor Show, but Tech-On says Denso hasn't decided when it will commercialize the system.