On the day that we humans finally hand over the car keys to robots, Ford wants to be sure that those robots will be able to communicate with pedestrians and others on the road just as human drivers can. How can a car with no one in the driver’s seat tell a kid on their bike that it is safe to cross in front of it?

In order to solve this problem, a driver with the Virginia Tech Transportation Institute got in the driver’s seat of a Ford vehicle dressed as the seat itself and drove around. Data gathered from that experiment was used to develop a windshield light bar, which Ford announced this week with the release of its self-driving safety report.

This bar, placed inside the car along the very top of the windshield, lights up with a different pattern depending on what the vehicle plans to do next. People on the street can quickly interpret these simple patterns and know what the car is about to do. For example, a white light moving back and forth means the car is yielding and it is safe to cross in front of it, while a rapidly blinking white light means it is about to move forward.