Brain waves make a fast brake

Drivers could stop cars just by thinking about it

In a fast-moving car, the brain can hit the brakes faster than the foot. By relying on brain waves that signal the intent to jam on the brakes, a new technology could shave critical milliseconds off the reaction time, researchers report online July 28 in the Journal of Neural Engineering

The work adds to a growing trend in car technology that assists drivers. Though it may eventually lead to improvements in emergency braking, the new brain signal technology isn’t ready for the road.

“As a basic science study, I was quite impressed with it,” says cognitive neuroscientist Raja Parasuraman of George Mason University in Fairfax, Va. “I just think a lot more needs to be done.”

In the study, computer scientist Stefan Haufe of the Berlin Institute of Technology in Germany and his colleagues measured brain wave changes while participants drove in a car simulator.

The participants drove around 60 miles per hour, following a lead car on a curvy road with heavy oncoming traffic. Every so often the lead car would slam on its brakes, so that the participant would have to either do the same or crash.

For most drivers, the lag between the lead car stopping and themselves slamming the brakes was around 700 milliseconds. Particular neural signatures were evident during this lag time, and they could be early indicators that the drivers wanted to brake.

“Our approach was to obtain the intention of the driver faster than he could actually act,” Haufe says. “That’s what the neural signature is good for.”

Haufe and his colleagues designed a system that detected and interpreted these neural patterns. In computer simulations, the system, which included EMG data from leg-muscle electrical activity, performed about 130 milliseconds faster than an unaided driver, the team reports. For a car traveling at 60 miles per hour, this time difference translates to about 3.7 meters of stopping distance — the length of some compact cars.

At peak performance, the system would incorrectly slam on the brakes almost two times per hour, a false alarm rate that needs to come down if the system is going to be useful, Parasuraman says. “We all hate alarms that go off when you have no danger, like the fire alarm that goes off when there’s no fire,” he says. “Even a 1 percent false alarm rate would not be acceptable to most people.”

And even if people could be convinced to wear the uncomfortable and obtrusive EEG cap while driving, introducing driver-assisting technology might bring another set of problems, Parasuraman says. People might become overly reliant on the technology and reduce their vigilance on the road.

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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