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 recruitedto 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 andthe 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 permissiveleft 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. Whenopposing traffic was present, drivers spent a majority of time focused onopposing traffic and would use this as a base point from which they wouldglance 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.
Abstract