Grace Roessling^1,2, Brett Fajen¹; ¹Rensselaer Polytechnic Institute, ²Carnegie Mellon University

Previous research has extensively explored the visual information used to control steering during driving, but less is known about the role of spatial knowledge of the road. The present study investigated whether drivers rely on knowledge of road geometry and the nature of such knowledge. Subjects performed a simulated driving task, using a steering wheel and foot pedals to drive along a set of ten winding tracks. Each track comprised straight segments interleaved with curved segments, some that were immersed in fog. Experiment 1 (N = 30) compared performance of subjects who drove the same track on all ten trials against subjects who drove a different track on each trial. Analyses focused on performance on the 10th trial, which used the same track in both groups. Subjects in the Constant Track group exhibited significantly greater steering stability and reduced lane position variability, but only when visibility was reduced by fog. They also performed better on post-tests that measured knowledge of road geometry in egocentric and allocentric reference frames. Experiment 2 (N = 60) tested whether the spatial knowledge used by drivers is better characterized as a globally cohesive cognitive map or as local landmark-to-road-segment associations. Three groups performed the same task as Experiment 1: a Control group similar to the Constant Track group from Experiment 1, a Scrambled Landmark group in which the track was the same on each trial but landmarks were scrambled, and a Scrambled Segment group in which the order of road segments was scrambled but landmark-road segment pairings were preserved. Steering performance was most affected by the manipulation of landmarks. We conclude that knowledge of road layout does play a role in steering control but only when visibility is reduced. Further, such knowledge is best characterized in terms of local associations between landmarks and road geometry.

Acknowledgements: NSF 2218220