Sleepy behind the wheel? Some cars can tell

Automakers are putting technology to work to stop drowsy driving

Mercedes’ Attention Assist system monitors the driver’s behaviors and checks them against 90 indexes.

NEW YORK — It’s something that many of us have experienced while driving, though we may not like to admit it.

It’s called a microsleep, a brief state of drowsy unconsciousness that can happen even if your eyes remain open.

Drowsy driving kills. According to the National Highway Traffic Safety Administration, drowsy driving caused 824 deaths in 2015, the last year for which figures are available.


Several manufacturers, including Audi, Mercedes and Volvo, currently offer drowsiness detection systems that monitor a vehicle’s movements, such as steering wheel angle, lane deviation, time driven, and road conditions. When drowsiness is detected, drivers are typically warned with a sound and the appearance of a coffee cup icon.

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But manufacturers and automobile suppliers are now working on advanced technological solutions that go beyond visions of coffee cups.

To find out if drowsiness can be detected even earlier, Plessey Semiconductors has developed sensors, to be placed in a seat, that monitor changes in heart rate. Algorithms developed by the company indicate when breathing changes to patterns that are typical of someone who is sleeping, giving a warning before someone actually feels tired.

“We could see this in a vehicle in five years,” said Keith Strickland, chief technology officer of the company, which is based in Plymouth, England.

Bosch, a German supplier of technology to automotive companies, is developing a camera-based system that will monitor head and eye movements, as well as body posture, heart rate, and body temperature.


In addition, sensors on the outside of the vehicle will monitor the state of traffic in which the fatigued driver is engaged. Once vehicles can communicate with each other — a capability expected in the next few years — other cars will be able to take appropriate maneuvers to avoid the drowsy driver.

In France, Valeo, a supplier of automotive technology, is developing an infrared camera system that will monitor children in the rear seat as well as the driver’s shoulder, neck, and head movements, looking for deviations from the norm.

Checking body temperature and even how the driver is dressed, the system will also be able to customize the interior temperature for each driver, said Guillaume Devauchelle, the company’s innovation director.

Nvidia — chip supplier to Audi, Mercedes, Tesla, and others — is developing the Co-Pilot, an artificial-intelligence tool that can learn the behaviors of individual drivers and determine when they are operating outside their norms.

The system will eventually learn a driver’s standard posture, head position, eye-blink rate, facial expression, and steering style, among other indexes. Based on a vehicle’s capabilities, the driver will be warned or driven to a safe spot when conditions warrant.


Advanced drowsiness detection systems exist today. Mercedes’ Attention Assist monitors a driver’s behavior for the first 20 minutes behind the wheel to get a baseline of behaviors. Then the system checks those against 90 indexes, such as steering wheel angle, lane deviation, and external factors such as wind gusts and pothole avoidance.

While NHTSA reported 824 deaths in 2015 because of drowsiness, the actual number is likely to be considerably higher, the agency said. Drowsy driving can only be self-reported and not measured like drunkenness.

“We’re a nation of tired drivers,” said Deborah Hersman, the head of the National Safety Council and the former chairwoman of the National Transportation Safety Board. “People talk about sleep deprivation as if it’s a badge of honor. As a society, we have to realize that drowsy driving is really dangerous.”