Washington State University Spokane researchers have designed and developed a novel method that determines a driver's drowsiness levels based on the steering wheel handling.

The patented technology based on steering wheel movements is deemed to be more reasonable and more consistent than the currently employed video-based driver drowsiness detection systems like psychomotor vigilance task (PVT).

The new technology incorporates a sensor that measures the position of the steering wheel. It could be either installed in the manufacturing process or as an aftermarket accessory.

"Video-based systems that use cameras to detect when a car is drifting out of its lane are cumbersome and expensive," Hans Van Dongen, research professor at the WSU Sleep and Performance Research Center, said in a statement. "They don't work well on snow-covered or curvy roads, in darkness or when lane markers are faded or missing.

"Our invention provides an inexpensive and user-friendly technology that overcomes these limitations and can help catch fatigue earlier, well before accidents are likely to happen," said Van Dongen.

According to the National Highway Traffic Safety Administration, drowsy driving leads to more than 100,000 crashes per year, causing 40,000 injuries and 1,550 deaths. In a 2013 Centers for Disease Control and Prevention study, 4.2 percent of 147,076 participants in 19 states and the District of Columbia (DC), reported to have fallen asleep while driving at least once during the last 30 days.

For the study, researchers put around 29 participants on a simulated 10-day night shift schedule that caused moderate levels of fatigue. During each night shift, participants took part in four 30-minute sessions on a driving simulator that recorded data related to speed, acceleration, steering, lane position and other factors.

Researchers said that the two most important factors that predict fatigue in drivers are variability in steering wheel movements and lane position. They found that steering wheel movements detect variability in lane position much earlier and it makes it possible to identify driver drowsiness before the car drifts out of lane.

"We wanted to find out whether there may be a better technique for measuring driver drowsiness before fatigue levels are critical and a crash is imminent," Van Dongen said. "Our invention provides a solid basis for the development of an early detection system for moderate driver drowsiness. It could also be combined with existing systems to extend their functionality in detecting severe driver drowsiness."

The finding is published in the journal Accident Analysis & Prevention.