(Radio Iowa) – As driverless cars become more popular on our roads, researchers at the University of Iowa are studying ways to make those cars transmit simple messages to pedestrians that it’s safe to cross in front of them. U-I Professor Jodie Plumert says they’re testing out one potential signal so computerized cars can let those on foot know they’re being “seen” by its cameras. “It had a light on the top, like a little dome light, and it was red,” Plumert says, “and then as it approached the intersection, it either turned green when the car began to decelerate, or it turned green just after the car came to a stop in front of the pedestrian.” The concept is being tested in a virtual reality lab at the U-I using projections of vehicles on giant screens that surround real kids, about a hundred of them so far, all between the ages of eight and 12. Plumert, a professor of psychological and brain sciences, says the results so far are revealing.

“When the cars were decelerating gradually and the green light came on early, children did enter the road before the car came to a complete stop,” Plumert says. “But when the green light came on, just after the car came to a stop, the children waited for that light to come on before they entered the road. So they were sort of treating it like it was a crosswalk signal and if it came on early, it was like, ‘Okay, I can go,’ and if it came on late, they waited for it to come on.” Autonomous vehicles need to be able to relay key information to pedestrians, she says, before even more of them enter the flow of traffic.

“This issue of — even if it were a car with a driver — if cars are decelerating gradually, seeing kids being willing to start crossing before that car came to a complete stop was another aspect of the study that was interesting — and also concerning about children’s traffic behavior.” Driverless vehicles are quickly gaining in numbers and Plumert sees them being used in big cities like Los Angeles already as a taxi service, as well as for making deliveries of shipments large and small. “This is kind of a whole new world,” Plumert says, “because here these these vehicles might be driving around and there’s no driver in there to communicate with you, like wave to you or make eye contact to say, ‘Yep, I see you and I’m gonna wait until you cross the road here.'”

The Insurance Institute for Highway Safety projects there will be three-and-a-half million vehicles with self-driving functionality on American roads by next year, and four-and-a-half million by 2030.