Accuracy of video analytics and onboard gps devices for data collection at roundabouts

Abstract

Roundabouts significantly reduce the number of vehicle conflict points at intersections while simultaneously reducing the speed of vehicles through intersections, thereby reducing crash frequency and severity. Accurately measuring the positions and speeds of vehicles traversing a roundabout in the field is challenging, but required to analyse operations at roundabouts. This paper reports on an investigation into different methods of measuring the positions and speeds of vehicles travelling through a roundabout. Ideally, continuous speeds, i.e., speeds measured at short intervals, are required for an accurate understanding of a vehicle’s movement through a roundabout. Comparisons are made between several devices and technologies that can provide the necessary vehicular trajectory data in roundabouts. These include external devices and/or technologies tracking the vehicle (speed gun, area radar scanning, video recording, and video analytics) and onboard devices using satellite positioning systems (Mobile Smartphone, VBox Sport, Garmin Handheld, and DL1 Club). These devices vary in terms of specifications, data recording frequencies, speed, and positional accuracy. The study showed that of the devices that were tested, GPS tracking, using specifically the VBox Sport device, and video analytics using UAV-based video footage provide the highest levels of accuracy.