Lane-based vehicular speed characteristics analysis for freeway work zones using aerial videos

Abstract

Work zones which are usually referred to as traffic bottlenecks or critical points may lead to reductions in both operational performance and safety. Researchers have conducted extensive studies on speed characteristics in freeway work zones. However, most of these studies are based on simulation data or are travel direction-based rather than lane-based. By utilizing the video recording capability of drones, this paper aims to provide methodologies and the workflow in exploring the vehicular speed characteristics in freeway work zones with considerations for lane and location deviations. A four-to-three lane work zone on Huhang Expressway between Downtown Shanghai and Songjiang in China was selected for data collection. Then free flow speed variation pattern is analyzed, a speed prediction model is proposed, and the speed–flow relationship is investigated on each lane at nine virtual sections along the work zone. It is found that the merging area affects the speeds mainly in the segment from 200 m upstream of the taper to the start of the activity area, which is the most important risk area in the work zone, and the speed characteristics depend on vehicle types (trucks versus automobiles) as well as lane locations. It is also showed that drones are valuable and effective tools for data collection for vehicular speed characteristics analysis in freeway work zones and it is easy to extract the information needed.