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.
