Develop Guidelines for New Vehicle Detectors at High-Speed Signalized Intersections

For many years, the traditional vehicle detection method that the Texas Department of Transportation (TxDOT) has used on high-speed signalized intersection approaches involved multiple detection points, with inductive loops being the early favorite in terms of technology. However, TxDOT districts began adopting video-imaging detectors to replace loops as video began to show sufficient improvement, even though they were not as accurate as loops. Later, following disappointing results from video implementation, TxDOT began investigating and installing newer detectors with hopes of both safety and operational advances but without full knowledge of how well the new detectors worked. Most of the newer systems overcame the challenges of traffic interference and compromised pavement integrity that plagued loops, and some appeared to improve detection performance over video. Based on this background, this research project: 1. Determined current TxDOT-specific needs for new vehicle detectors. 2. Identified the most promising detectors for both stop line and dilemma zone detection. 3. Developed guidelines on each new technology and established recommended settings to guide TxDOT on installation and use of each detector and combination of detectors.