The research behind that mysterious ‘driverless’ car spotted in DC last month

You may remember the story of the “driverless” car in the D.C. area that made the rounds last month and caused a few days of confusion.

While it appeared that no one was at the wheel, the Virginia Tech Transportation Institute later revealed that it was part of research which featured a driver dressed up as a seat. The “seat suit” involved a top designed to match the car’s interior, a mask that mimicked the seat rest and his hands held low on the steering wheel to avoid being seen.

Such “driverless” cars are both a curiosity, but they’re not just designed to get attention on social media. The car used in this case was designed to present a communication problem. As a pedestrian or a driver, you may not notice how often you rely on visual signals to know what another driver plans to do — until you are faced with a car that appears to be empty.

Last week, Virginia Tech released the results of the experiment to the public, and said the 150-hour, 1,800-mile test was the result of a partnership with Ford.

John Shutko, Ford’s Human Factors Technical Specialist for Self-Driving Vehicles, wrote in a blog post that the study filmed drivers and pedestrians to explore how they interact and communicate with a vehicle that lacks a traditional driver. The Institute also used the test to puzzle out how to communicate the same information about the car’s intentions without a recognizable human face in the driver’s seat.

Researchers considered several different options for how to communicate whether the car was moving at a steady pace, accelerating from a stop or coming to a halt to yield to a pedestrian or other vehicle. Eventually, they decided that the best way to communicate was to place a long, lighted bar along the top of the windshield. It indicated the car was moving at a steady pace with a solid light, show that it was accelerating from a stop by blinking rapidly or to give a clue that it was slowing down by using lights that sweep from side to side.

An example of the light bar. (Image courtesy of Ford)

Virtual-reality tests with a similar setup showed that users had to adjust to get used to the new signals. However, Ford and Virginia Tech researchers also explained their rationale for devising a new communication system for their vehicles. They considered using textual cues, but realized that might be impractical for linguistically diverse countries. They also considered using lights signal that mimicked stoplights, but were prevented by laws that regulate colored lights on cars, leaving the white lights they devised as the best option.

To provide greater accessibility on this issue, the company says that it is still researching how to communicate with the blind or visually-impaired.