Parents fretting about their teenage drivers have a technology weapon to look forward to: a dashboard-mounted fatigue monitor that can rouse someone who seems in danger of driving off the highway. About two-thirds of drowsy-driving crashes in the United States involve drivers between 16 and 29.

Last fall, Attention Technologies, a startup in Pittsburgh, PA, introduced a ­webcam-­sized drowsiness monitor for truck drivers, based on research at Carne­gie Mellon University. It shines invisible infrared light onto a driver’s retina and measures the reflection. If the reflection is blocked too often–indicating that the driver’s eyes are having trouble staying open–the device flashes and beeps.

Now the company is planning a mass-market version that could sell for less than $100 (compared with up to $1,500 for the current versions), thanks largely to the falling cost of digital camera components and signal-­processing chips. The company is also working on a new feature that tracks the driver’s gaze angle–indicating whether he or she is actually watching the road. “We think we’ll be able to get mothers to buy this for Johnny who’s going off to spring break for the first time, or for their road-warrior husbands,” says Richard Grace, the company’s founder and CEO. He anticipates bringing the cheaper version to market within two to five years.