Identifying Sources of Discomfort in Various Road Events While Riding Automated Vehicles

The present study aimed at exploring the factors that induce discomfort when riding automated vehicles in various driving events. Using a Wizard-of-Oz design, participants were driven in what appeared to be a fully automated (level 5) vehicle. An analysis of participants’ reactions and verbal utterances revealed six specific sources of discomfort (Vehicle’s speed, Crossing Traffic, Pedestrians, Road Geometry, Road Markings and On-coming Traffic). These discomfort reactions were then cross-referenced to the road events they were associated with. The results suggest that there is a different set of discomfort sources associated with each unique road event. Overall, we identified seven distinct categories of road events that could cover the entire experimental route (Crosswalks, Roundabouts, Straight Intersections, Left-Turns with On-coming Traffic, Left-Turns without On-coming Traffic, Right turns with Right-of-way and Right turns without Right-of-way). From a design perspective, these findings can empower the development of interventions to reduce discomfort in automated vehicles.