Development of Intersection Performance Measures for Timing Plan Maintenance Using an Actuated Controller: Phase 1

014566322012FINAL REPORTPDFTech ReportFHWA-AZ-09-663SPR-PL1 (173) 663Traffic actuated controllersActuated traffic signal controllersTraffic signal timingTraffic dataTraffic flowResearch HubData and Information TechnologyHighwaysOperations and Traffic ManagementI72: Traffic and Transport PlanningArizonaUnited StatesArizona. Dept. of Transportation. Research CenterSmaglik, Edward J.Roberts, Craig A.Northern Arizona University. Arizona Laboratory for Applied Transportation ResearchArizona. Dept. of Transportation. Research CenterUS Transportation Collection"This proof-of-concept study is to develop an automated data collection module for collection and management of traffic data at signalized intersections controlled by the Arizona Department of Transportation (ADOT). The objective of this proof-of-concept phase of the work was to determine the feasibility and cost of modifying an existing ADOT traffic control cabinet to collect operational data using the video equipment installed for presence detection to capture vehicle flow rate information. The goal was to use this data to develop event-based performance measures, leveraging existing infrastructure to its fullest extent. An intersection in Flagstaff, Arizona, was chosen as the test location. Researchers used the intersection\u2019s existing video detection cameras, installing additional video detector interface cards to produce contact-closure vehicle flow rate information. Researchers calculated performance measures (volume-to-capacity [V/C] ratio, equivalent hourly volume [EHV], and cumulative counts) from the video-generated data and compared them with measures generated from concurrent manually counted data over a 24-hour analysis period. The V/C values generated from the video data were shown to be statistically different than those calculated with manual-count data; however, on all but one phase, the difference was not operationally significant. An analysis of cumulative count data did show operationally significant differences. While the data had some inaccuracies, the proof of concept was successful in that the research team was able to generate traffic volume performance measures using existing video detection equipment. During the next phase of the project, the data inaccuracies can be investigated and possibly addressed with measures such as camera placement, choice of technology, etc. A cost analysis determined that the cost of equipping a similar intersection for this type of vehicle count capability is approximately $16,700 using the equipment specified for this project if the installation is performed as part of the initial construction or rehabilitation of the intersection. The researchers recommend that Phase 2 of this project be undertaken. Ultimately, assuming successful completion of all phased milestones, the investigators recommend that ADOT consider equipping future intersections as described in this report to improve the quality of future signal-timing plans while reducing costs over the long term.