Site-Based Video System Design and Development

The goal of the Strategic Highway Research Program 2 (SHRP 2) Safety program is to prevent or reduce the severity of highway crashes through more accurate knowledge of driver behavior and other factors. The Safety program’s research is proceeding along two distinct but related tracks: (1) the in-vehicle, naturalistic driving study, which encompasses all types of driving, and (2) the site-based risk study, which focuses on vehicle trajectories at specific locations, such as intersections. This report describes the work that was done in the latter track to develop and test an on-site, video-based data collection system with the potential for widespread application by researchers and state and local authorities to examine intersection safety. This report documents the development of a prototype system capable of capturing vehicle movements through intersections by using a site-based video imaging system. By tracking individual vehicles through an intersection, the Site Observer provides a basis not only for viewing crashes and near crashes but also for developing objective measures of intersection conflicts and collecting before-and-after data when design or operational changes are made at intersections. It also yields detailed and searchable data on the normal driving population so that exposure measures can be determined. This research built on previous work on video-based systems to develop a system that is relatively inexpensive, portable, and flexible enough for installation at all types of intersections, as well as robust enough for use in locations with a wide range of environmental conditions. The system embraces modern machine vision cameras and draws from the large body of research on algorithms for extracting information from video streams, a key advantage where data must be collected continuously. It was tested at a location during fall and winter months and found to operate as designed. The Site Observer is a robust prototype system that is deployable as is but is also capable of further development and refinement for use in intersection safety assessment.