Using an automated vehicle’s lateral deviation to communicate vehicle intent to the pedestrian

Abstract

Highly automated vehicles may lead to vehicle occupants getting distracted from driving-related tasks, so it may be necessary to introduce at new modalities to achieve effective pedestrian-vehicle communication. This research proposes using the lateral deviation of the automated vehicle within its lane as a method to communicate if it is going to yield to the pedestrian. In a crowdsourced experiment, videos containing an approaching automated vehicle were shown to participants. The effect of 1) levels of deviation (no deviation, deviation of 0.4 m, 0.8 m and 1.2 m), 2) direction of deviation (towards pedestrian, away from pedestrian), 3) vehicle behaviour (yielding, not yielding), 4) onset of deviation (onset at a distance of 50 m and 30 m from the pedestrian), and 5) intended vehicle path (vehicle going straight, vehicle taking a turn) were studied. A between-subjects design was used to assign participants (total N = 945; and after filtering, N = 638) randomly to one of 4 groups based on 1) the deviation direction-behaviour mapping (deviation towards pedestrian was ‘yielding’ and away was ‘non-yielding’, deviation towards pedestrian was ‘non-yielding’, away was ‘yielding’) and 2) instructions at the experiment start (not informed of the vehicle deviation, informed of the deviation). Each participant viewed 28 videos, and the task was to press and hold a key as long as it felt safe to cross. The results showed that 1) vehicle deviation to indicate yielding led to a statistically significant improvement in willingness to cross, for all four groups 2) the deviation level was significant when comparing the two extreme values (0.4 m and 1.2 m) for the yielding trials in two of four groups, 3) for one group there was a statistically significant difference in willingness to cross when the vehicle indicates that it intends to take a turn versus when it intends to go straight ahead. It is concluded that lateral deviation of the vehicle, when used to communicate yielding intent. affects the pedestrians’ willingness to cross the road.