Alternative Vehicle Detection Technologies for Traffic Signal Systems: Technical Report (0-5845-1)

Due to the well-documented problems associated with inductive loops, most jurisdictions have replaced many intersection loops with video image vehicle detection systems (VIVDS). While VIVDS have overcome some of the problems with loops such as traffic disruption and pavement degradation, they have not been as accurate as originally anticipated. The objective of this project is to conduct evaluations of alternative detector technologies for application into the state's traffic signal systems. The research will include investigating the available detectors that could replace loops or VIVDS through a literature search and agency contacts, followed by field and /or laboratory investigations of promising technologies. Deliverables will include a research report, a project summary report, and a detector selection guide. Findings indicate that three detectors should be considered as alternatives to VIVDS for signalized intersections - one is a radar detector and the other two are magnetic detectors. The radar detector is only for dilemma zone detection and does not cover the stop line area. The other two are point detectors, so their basic function would be for loop replacements. One is an intrusive detector, requiring a short lane closure for installation and replacement. Field testing of performance for all three detectors indicated they are worth considering as inductive loop or VIVDS replacements.