Tracking Driver Eye Movements at Permissive Left-Turns

Abstract

The objective of this analysis was to identify sources of information used by left-turning drivers. To complete the experiment, a virtual network of signalized intersections was created for use in a driving simulator equipped with head and eye tracking equipment. Fourteen drivers were recruited to participate in the experiment, which included two independent variables (permissive signal indication and presence of opposing traffic). The primary dependent variable was the associated eye movements at permissive left-turns, including the magnitude of time focused on each potential cue and the pattern in which cues were detected. To complete the analysis, eye movements were tracked and the screen was divided into “areas of interest,” which coincided with potential cues used in the completion of a permissive left turn. For each permissive scenario, drivers used more total cues when no opposing traffic was present. Specifically, in the absence of opposing traffic, drivers fixated on a wider array of available information. When opposing traffic was present, drivers spent a majority of time focused on opposing traffic and would use this as a base point from which they would glance at other data sources. Overall, drivers looked at least once at the protected/permissive left-turn (PPLT) signal display and the opposing traffic stream. Drivers tended to scan the intersection from right to left, after initially locating the PPLT signal display and opposing traffic and/or stop bar area. The results of the eye movement analysis are consistent with data obtained in a follow-up static evaluation.