Evaluation Of Overhead And In Ground Vehicle Detector Technologies For Traffic Flow Measurement PDF Download

This report covers the Phase A and B activities of Research Project SPR 627 for the Arizona Department of Transportation (ADOT). Phase C is planned as a separate research activity and is anticipated to begin in the near term, following the completion of Phases A and B. The need for a better valuation program for new traffic detection systems came in part from a lack of confidence in existing detectors, as well as the need for non-intrusive detectors to replace failing embedded inductive loops. The primary objectives of this research were to identify the most promising vehicle detection technologies to meet ADOT needs, to identify candidate test sites, to develop a field test evaluation plan, and to develop and deliver a detailed design of the detection testbed on the selected segment of freeway. The Texas Transportation Institute (TTI) met these objectives through an Internet and literature search, a state-of-the-practice review, a search of relevant new detector systems, and through meetings with the Technical Advisory Committee (TAC). Relying on TAC input, TTI developed first a conceptual design, followed by a detailed design and budget for a proposed test facility located on I-10 in Phoenix just west of the 16th Street interchange. Detectors selected for test in the initial period of 12-plus months during Phase C (and the technology used) are as follows: Wavetronix SS-125 (microwave radar), Sensys Networks (magnetic), Global Traffic Technologies microloops (magnetic) and Autoscope Solo Pro (video imaging). The baseline system selected for providing ground truth data is the Peek ADR-6000 using inductive signatures as its basis of detection. It is anticipated that this Phase C testing will include two summer seasons to expose selected detectors to the extreme heat and related environmental conditions found in the Phoenix. The initial cost of the testbed will include detectors sufficient to ultimately cover eight lanes in the westbound direction (currently seven lanes) and six lanes in the eastbound direction. Besides the detectors, the total cost estimate includes a 12 ft by 12 ft node building, three equipment cabinets, inductive loops for the baseline system, conduit, and boring. The total cost of the facility is estimated to be approximately $566,000.