Investigating Vehicle Speed Interdependence in Work Zone Merging Scenarios

Merging behavior in work zones with lane closures involves complex interactions, often among multiple vehicles. Although the merging maneuver of a vehicle is contingent on the behavior of surrounding vehicles, much of the existing research fails to consider the interdependence of these interactions. This oversight has resulted in a significant knowledge gap within the literature on work zone merging behavior. To address this gap, this study examines how the speeds of vehicles surrounding a merging vehicle, specifically the lead and following vehicles in both the open and closed lanes, collectively influence merging speed decisions. Video data from two work zones in New South Wales, Australia, were analyzed using a simultaneous equation modeling approach to capture the endogenous relationships among vehicle speeds. The results revealed significant interdependence, particularly between the merging vehicles and following vehicles in both closed and open lanes. The findings underscored the coordinated and interdependent nature of vehicle speed adjustments during lane merging, where the merging vehicle’s speed both influences and is influenced by surrounding traffic in their current lane (closed lane) and target lane (open lane). The use of a system-level modeling approach proved essential to capture these reciprocal dynamics and the temporal interplay among vehicle responses. These findings suggest that modeling merging decisions without accounting for these mutual influences may overlook critical safety concerns, especially in mixed-traffic environments involving heavy vehicles. The study provides new insights into vehicle interactions in work zones, with implications for improving traffic management and safety assessments in such settings.