Performance Evaluation of Different Detection Technologies for Signalized Intersections in Minnesota

Project summary:

Intersection control can be pre-timed or vehicle actuated. Modern controllers implement natively only actuated control with pre-timed implemented as the special case of actuated, termed vehicle recall. Actuated signals respond to the traffic present at the intersection, so that the pattern of the signal (the length and order of each phase) depends on the traffic and can be different at every cycle. In all versions of actuated control, the cornerstone of the system is vehicle detection. MnDOT and many local Minnesota agencies have traditionally used embedded loop detectors in the pavement for detecting vehicles. Although the performance of a well-placed loop detector has yet to be matched by any other method, changes in the vehicle fleet (higher use of non-ferrous material) as well as increased need for more comprehensive detection (vulnerable road users, all lanes individual advance, and stop line detection) has resulted in the increased use of non-intrusive detection technologies (NIT). Testing of these newer technologies on Minnesota intersections has not been conducted in a comprehensive way. Studies evaluating the performance of NIT detection have been racing against obsolescence given the rapid development in the market. Regardless, several have identified the general pros and cons and have established some baseline comparisons. Unfortunately, there have been very few studies identifying the true costs of operating and maintaining such intersection control systems. This project aims to provide guidance to MnDOT and LRRB members on selecting the most appropriate technology for a given location as well as on the expertise, effort, and material cost involved in maintaining each of these systems year-round in Minnesota. The project guidance will be organized on a decision tool to guide signal design by MnDOT and other public works entities in Minnesota.