• 02.05.14

Could Cell Phones Stop Drivers From Hitting Pedestrians?

German researchers propose using radio signals so that cars can track pedestrians stepping into traffic. A major cell phone manufacturer has already expressed interest in the technology.

Could Cell Phones Stop Drivers From Hitting Pedestrians?

It has already been a rough year for pedestrians in New York City. As one of his first acts in office, Mayor Bill de Blasio embraced “Vision Zero,” an initiative aimed at completely eliminating traffic deaths in the city. That very weekend, four NYC pedestrians were killed in traffic, underscoring the need for dramatic action. At one intersection on the Upper West Side, three people were killed by cars in less than two weeks in January.


No one solution will make streets totally safe for pedestrians and cyclists, but researchers at the Technical University of Munich (TUM) have an idea. They are working on an assistance system, currently in the prototype phase, that could warn drivers when a pedestrian is about to step out into the car’s path.

Called the Ko-TAG system, the on-board positioning system placed in a car relays radio signals to a specific sensor carried by pedestrians. By bouncing signals back and forth between a transponder carried by a pedestrian and the sensor within the car, Ko-TAG can compute how far away the person is, and what direction she’s moving in, allowing the unit within the car to predict whether a collision is likely. Using this information, a driver could be alerted to a person striding out into the street from behind a large truck, for example, hidden from view, and if a collision is imminent, it can trigger the car’s emergency brake, stopping the vehicle before the driver even sees the pedestrian. Almost anything that can send or receive signals could be set up to be a transponder, even, cell phones, which pretty much every pedestrian is carrying around anyway.

Obviously, no one wants a car to brake every time a pedestrian stands near the edge of the sidewalk, so the potential for false alarms is high. Ko-TAG’s creators aren’t entirely transparent about how they can prevent this, though the research lab’s website indicates the risk assessment algorithm would prevent false alarms: “With the data obtained from the tracking of detected objects, such as direction of movement, distance and speed, the situation can be evaluated comprehensively and—in combination with suitable movement profiles–the collision risk can be assessed precisely.”

Erwin Biebl, a professor at TUM, tells Co.Design that “the transponder contains inertial sensors, that we use to send information about the kind of movement (walking, running, standing, riding a bike…) to the car. Thus, a person standing on a corner is no problem, since the probability value of a collision would be very low.”

The prototype has been tested using trained drivers and pedestrians in a real urban environment, Biebl says. It’s not that much of a stretch to think our phones will have this transponder capability in the near future. According to TUM, a major (unnamed) cell phone manufacturer has expressed interest already. Just hope you’re ready to let any vehicle on the block track your every movement. For safety, of course.

About the author

Shaunacy Ferro is a Brooklyn-based writer covering architecture, urban design and the sciences. She's on a lifelong quest for the perfect donut.