The Danger-Sensing Driver's Seat

A haptic car seat pokes you in the ribs when an accident looms

Photos: Arthur McClung III

Buzz, Buzz: Vibrating motors warn of cars in a driver's blind spot.

Today’s carmakers boast of their new vehicles’ cocoonlike qualities, including the latest noise-reducing features and great shocks that smooth out those bumps on the road. Myriad warning alarms are designed to counteract the insular environment when there’s trouble, but Yale University engineers are looking for a more subtle approach to signaling: vibrating motors and movable cams that send signals straight from the seat back to your back.

Such a system could be particularly useful for warning you of cars in your blind spot—an area you can’t see with either the side-view or rearview mirrors. The blind spot is blamed for sideswipe accidents that occur by the hundreds of thousands every year. Today’s blind-spot monitors warn you by flashing a signal in the rearview mirror or on the car’s dashboard.

But according to John Morrell, a former Segway engineer and now an assistant professor of mechanical engineering at Yale, a visual signal is the wrong one to send. The visual sense, he says, is already saturated in a car. On top of that, Morrell adds, an alert that appears in front of you about something that’s behind you means you have to translate the information, costing crucial response time as well as mental effort that could distract you from other dangers.

Instead, Morrell’s lab has designed a car seat that acts as a tactile interface between the driver and the environment. It uses vibrating motors as well as servos that press on the driver’s back to signal the location of a following car.

The ultimate goal is a ”renaissance user interface,” Morrell says of the design, ”using the mind and body to the fullest.” The design was inspired by his work at Segway, where ”every part of your body is coupled into the experience.”

A demonstration setup includes a modified car seat, a steering wheel, foot pedals, and a computer running an open-source driving simulator called TORCS, short for ”The Open Racing Car Simulator.” Twenty cellphone-motor tactors are arranged in a rectangular array across the back of the seat. A car coming up directly behind the driver in the simulation activates the center vibrators, while a car to the right or the left will activate the same-side vibrators, giving the driver a directional cue. The closer a car gets, the more intense the vibration. Two cams on each side add to the signal strength by pressing on the driver’s rib cage when a car shows up on either side.

In their preliminary study, the Yale engineers calculated the time a driver spent with another car in its blind spot during a ”commuting exercise.” Drivers were also given simultaneous math tasks to simulate distraction during driving. The results showed that the vibrotactile feedback improved drivers’ performance over that attained by using the rearview mirror alone.

It’s not the first time engineers have experimented with tactile signals to compensate for sensory overload during driving. Researchers at General Motors and TNO, a Dutch research organization, found that test subjects could actually pick up directional cues from a vibrating seat cushion while driving. Such a system could provide direct navigation information or even help warn of imminent collisions.

If systems like these turn out to be useful, car interiors will stay peaceful but may get more informative.

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