Drowsy driving causes more than 100,000 crashes a year, resulting in 40,000 injuries and 1,550 deaths, according to the NHTSA. That's where fatigue-warning technology comes into play.
Lachnit says there are two types of fatigue warnings -- one that monitors the driver's face or eye movement and another that monitors driving behavior, such as sudden lane or steering changes. When fatigue is detected, an alarm sounds.
Because fatigue warning is relatively new, the jury is still out on how effective this technology is, says the Insurance Institute for Highway Safety. "Those features that include automated braking or correction are far more effective than those with just a warning," Lachnit says.
In other words, this car safety feature might wake you up if you fall asleep, but it won't automatically correct driving to avoid a crash like forward-collision avoidance would.
Currently, fatigue warning is confined to just a few high-end manufacturers, and it might not ever become standard, Lachnit says.