Tech’splaining: Mercedes-Benz Active Emergency Stop Assist

  • Benjamin Preston is an automotive journalist whose work has appeared in the New York Times, Time, the New York Daily News and The Guardian, among other publications. His work has taken him from his Brooklyn home to a few war zones, from Baghdad, Iraq to the Detroit auto show.

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It has happened to many of us: You’re driving at night; you’re tired and fighting to keep your eyes open. All of a sudden, you awaken with a jolt as your car lurches onto the rumble strip on the median. That’s if you’re lucky.

The U.S. Centers for Disease Control and Prevention (CDC) reported at the end of 2018 that 1 in 25 adult drivers claimed to have fallen asleep at the wheel in the previous 30 days. But not all drivers who fall asleep at the wheel live to tell the tale.

While plenty of people wake up to the jarring vibration of wheels on the rumble strip, others aren’t so fortunate. According to the National Highway Traffic Safety Administration (NHTSA), drowsy driving caused an estimated 72,000 crashes, 44,000 injuries, and 800 deaths in 2013 alone.

National Safety Council (NSC) statistics for drowsy driving fatalities are much higher; the organization says there are more than 6,400 each year. The NSC likens driving while tired with driving under the influence of alcohol, pointing to research that equates losing two hours of sleep with the effects of drinking three beers. The sleepier you are, the more “intoxicated” you become.

To counter the effects of drowsy or distracted driving, Mercedes-Benz developed a technology that will stop a vehicle in its tracks if it detects the driver has stopped paying attention or is not actively piloting the vehicle. Dubbed Active Emergency Stop Assist, the system is part of a suite of active safety technologies that works when Active Steering Assist is activated. Active Steering Assist, for its part, helps the driver by following lane markings, other vehicles, and features parallel to the road to maintain the vehicle’s course with a minimum of effort from the driver. All the driver has to do is pay attention.

How Active Emergency Stop Assist Works

Mercedes-Benz Active Emergency Stop Assist
Active Emergency Stop Assist stops the car when the driver is no longer engaged with the steering wheel. (Mercedes-Benz)

There’s a lot of talk about fully autonomous cars right now, and the technology is sure to affect our lives sooner or later. But it could be a while until government agencies and safety groups work out the messy details surrounding regulating cars and trucks that drive themselves. In the meantime, a number of manufacturers have developed what could be called semi-autonomous technologies, among them Mercedes-Benz’s various driver-assist systems.

Adaptive cruise control, which allows the driver to set the vehicle’s target speed while radar sensors and cameras modulate actual speed relative to the position of the vehicle ahead, is the most basic type. More and more manufacturers – particularly Mercedes-Benz, Cadillac, Tesla, and Volvo – offer vehicles that can control speed and steering (although Cadillac has the only system that will pilot the car for long distances without the driver’s hands on the wheel).

The Mercedes-Benz version is really an advanced cruise control system, as the driver must maintain manual contact with the steering wheel at all times. Attention Assist monitors your driving style to find aberrations – unexpected steering, braking, and speed modulation inputs – that indicate drowsy driving so that the driver can be alerted when it’s time for a rest.

Active Emergency Stop Assist goes several steps further (as long as Active Steering Assist is on). When the driver is no longer interacting with the steering wheel, the system flashes a light and sounds a tone to alert the driver to return his or her hands to the steering wheel. If the driver still doesn’t respond, the system applies the brakes while maintaining the lane in which the vehicle is already traveling.

When the vehicle’s speed drops below 37 mph, the system switches on the hazard flashers to alert vehicles traveling behind that a stop is imminent. The car will then come to a complete stop, at which point the parking brake is automatically engaged and an emergency call placed. The doors unlock automatically, too, to allow access to first responders should medical attention be necessary.

Just Say No! Driving Drowsy is Like Driving Drunk

Mercedes Benz on Intelligent World Drive Tour
Adaptive cruise control and driver alert systems work in concert to help the driver avoid crashes. (Mercedes-Benz)

This system certainly covers someone who has fallen asleep at the wheel, but also greatly improves overall road safety in the event that a driver has a medical emergency in which limited capacity or loss of consciousness pose a threat to the driver and other motorists. And for anyone who has ever felt completely helpless while a big sneeze temporarily blinded them behind the wheel, think of the protection a system like this could provide.

Of course, before computers take over driving duties completely, it’s best to avoid driving drowsy to begin with. No one wants to be the one who stops in the middle of a busy highway, even if it’s a better alternative than crashing into the guardrail.

The CDC says that those most likely to drive drowsy are people who haven’t had enough sleep (obviously), bus and truck drivers, laborers who work long shifts or late shifts, people with untreated sleep disorders such as sleep apnea, and people who use medications that cause drowsiness. The warning signs that someone is too tired to drive include yawning or frequent blinking, difficulty remembering recent road features, missing turns and highway exits, drifting from lane to lane, and straddling lane markings.

And if you’ve driven onto the rumble strip at the side of the road, you need to pull over ASAP and take a break or a nap.

About the Author

  • Benjamin Preston is an automotive journalist whose work has appeared in the New York Times, Time, the New York Daily News and The Guardian, among other publications. His work has taken him from his Brooklyn home to a few war zones, from Baghdad, Iraq to the Detroit auto show.

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