The Design Lab, UC San Diego
Using Wizard-of-Oz Techniques to Explore Pedestrian Communication with Autonomous Vehicles
Above: Malte (post-doc) steps inside the “self-driving golf cart.”
Autonomous vehicles can’t gesture and maintain eye contact like human beings can, giving one less method of resolving ambiguous traffic situations on the road. In the absence of any direct communication from the autonomous vehicle, how will human pedestrians react?
Challenge: We don’t have access to an autonomous vehicle.
Approach/Workaround: Since we did not have access to an autonomous vehicle, we decided to outfit a golf cart with one-way mirrors and asked the driver to drive in a “robotic manner” (no erratic movements, following a pre-determined track), thereby concealing fact that there is a human operator.
Goal #1: A moveable art exhibit. Stir public interest in the design lab’s research, and showcase the diverse projects being explored in San Diego as part of the city’s first public Design Forward event. The event was attended by families, designers, and industry leaders in San Diego county. In this sense, the self-driving golf cart was “an art exhibit”.
Goal #2: Generate research questions. A Wizard-of-Oz pilot experiment like this can’t falsify a hypothesis, but initial observations can help generate new questions to pursue in future experiments. We didn’t want to waste this opportunity to gauge public reactions to “autonomous vehicles”. Would people even notice that the golf cart was “self-driving” in the first place? And if they did, how would they behave differently? Or not?
Result: Most people cross in front of the cart as if nothing unusual was going on. Perhaps direct communication between the driver and pedestrian is not as critical to negotiation of safe passage as we once thought it was? Our observations served as the inspiration for the next iteration of the self-driving golf cart — the “seat suit” project.
“The Seat Suit” – Phase Two
After the self-driving golf cart experiment, we wanted to expand our pilot study beyond Broadway Pier (a closed environment with pedestrian traffic), and into public roads with cars, bicyclists, and pedestrians all in the same place.
Why: After conducting our ethnography of communication in urban road environments, we had a hunch that vehicle motion and position played a larger role in road user communication than we originally expected. Eye contact and direct signaling via gesture (e.g. hand waving) was not as common as we originally thought. Many people don’t even look at the driver or confirm that the vehicle has made a full stop when they determine that it’s safe to cross.
Method: We made a homemade seat-suit with wire mesh and seat fabric, and put our lead researcher Colleen Emmenegger inside. (Malte and I wouldn’t fit anyway). Colleen would then drive around campus roads, downtown La Jolla, and Clairemont (suburban San Diego neighborhood) while wearing the seat suit. Malte Risto and I would sit in the back row of the car, watching for incoming traffic and pedestrians. We attached three cameras to the roof of the car to gauge public reactions — one camera facing the rear, and two cameras facing the left and right halves of the front bumper.
Result: What’s surprising is that most pedestrians were not surprised at all by the vehicle setup — they crossed the street as they normally would, even waving to the “empty” seat. Drivers in four-way stop intersections would do the same. Pedestrians that noticed there was “no one” in the front seat usually only noticed after they had crossed the street, or if they were in a position where negotiation of safe passage on the road was not critical.
This exploratory study gave further evidence for the primacy of vehicle movement and position in communicating intent on the road, as opposed to human gesturing and eye contact. There was also a press release in the San Diego Union-Tribune featuring this particular part of the project, featuring interviews with Colleen Emmenegger and Don Norman.
Bonus: Only one pedestrian flipped the car off during the video recording.
Deliverables & Impact
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Reflections
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