Autonomous Shuttles: The Trouble With Pedestrians

Last week, a Navya self-driving shuttle in a residential Vienna neighborhood bumped into a pedestrian. The female walker reportedly received only minor injuries--thankfully--but the fact that the slow-moving shuttle tagged her at all shows how difficult it is to deal with people traipsing across the street.

I've witnessed incidents between stubborn pedestrians and cautious autonomous shuttles, and the challenges are not minor. Every driver knows that pedestrians behaving badly is a reality of urban driving. People jaywalk, they stare at their phones while stepping out into traffic, they emerge from between parked cars, they even play chicken with drivers at busy intersections. And when there's an accident, pedestrians always come out on the losing end.

So autonomous vehicles have to be programmed to handle the challenge. The results can seem overly cautious and sometimes comical.

I was in a Navya shuttle on a closed course, for example, when an older pedestrian along the route became too inquisitive. The shuttle stopped and then started honking at him. The pedestrian was close to the edge of the route, but clearly didn't intend to step in front of the $250,000 shuttle--but he refused to budge. The result: an autonomous driving standoff with the elderly man waving and yelling at us (you stupid kids!) while we--the passengers--waved and yelled at him to step back.

If you're thinking, well, a machine learning program (AI) could understand his hand gestures and make the vehicle go ahead, think again. The man was angry at us, the humans in the vehicle. There was nothing about his hand gestures that made it clear he wanted the shuttle to proceed (he seemed to be indicating we should take some other intimate action upon ourselves). A so-called AI program would not or could not have made a driving decision based on the obscene gestures.

One obvious and safe solution--but less technically cool idea--would be to have the vehicle simply say, out loud, in English (or in this case, Français), "Please step back from the vehicle so we can proceed." (This is like articulated vehicles that announce, "Watch out, bus turning.")

Is it an elegant solution to the trouble with pedestrians? Does it make for a really slick demo? No, and no. But it is based on simple and straightforward systems of interaction that work today. And it reminds us that you shouldn't try to reinvent the wheel when some of the best ideas are right in front of our self-driving sensors.