If you're one of the 40% of Americans who say they've nodded off at the wheel, then Ford Motor Co. may have news that will jump-start your next moonlight drive.

The giant automaker is rolling out a lane-keeping technology that can recognize drowsy drivers and help them stay alert and in their lane. The announcement is significant, not only because drowsy driving is so common, but also because Ford is delivering the technology to mid-level vehicles, instead of just luxury-class cars. Ford said it will launch the technology in early 2012 on the Ford Explorer.

"This is a huge change," said Michael Kane, vehicle engineering supervisor for driver assistance technologies at Ford. "We're putting this technology on vehicles that the common person will be able to afford."

The key to the new technology is a rearview mirror module that contains a pair of microcontrollers (MCUs) and a camera. The first of the two MCUs incorporates an image processor that handles data from the camera. The second runs software that examines the light and dark images and determines if the driver is inadvertently crossing over the lane lines.

"The camera is like an eye -- we can only react to what it can see," Kane told us. "But we worked with our suppliers to make sure that, even under different environmental conditions, we have the best opportunity to see the lines."

The software is robust enough to know if a driver is unintentionally leaving the driving lane, Kane said. It can recognize lane lines at night and on wet highways. It also watches to see if the driver is using the car's turn signals. If so, it suppresses any alerts.

"We have an amazingly complex algorithm," Kane said. "We don't want it to intrude on the driver's experience. We only warn them when we fully believe they need to be warned."