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Inventory of System Operations Data Collection and Use in the Virginia Department of Transportation
Catherine C. McGhee
Catherine C. McGhee
Year: 2006
VTRC No.: 06-R21
Abstract: Accurate data describing the status of the transportation network is the backbone of system operations management. Without accurate data, traffic engineers cannot optimize signal phasing and timing, effective incident management cannot be undertaken, decisions regarding managed lanes operations cannot be made effectively, and information cannot be shared with the traveling public. Traditionally, the data collected for all of these uses have been basic flow parameters, i.e., volume, speed, and occupancy. These data may be collected from continuous count stations, through special or project-related collection activities, or as part of an infrastructure-intensive traffic management system such as the Virginia Department of Transportation's (VDOT) Smart Traffic Centers (STCs). The biggest shortcomings of these data sources are that they tend to be limited in geographic scope or not continuous from a temporal perspective. In addition, the data are often considered for use by only the original "owner" or entity that collected them. The purpose of this project was to develop a comprehensive inventory of operations (traffic flow) data collection activities that occur within VDOT and to document the uses of the data collected. The results of the study indicate that the majority of traffic flow data used in VDOT come from the Traffic Engineering Division's traffic monitoring system. All data collected are archived and accessible via the internal VDOT website. Data are also collected in VDOT's district offices and through the STCs deployed in Northern Virginia and Hampton Roads. Currently the STC data are rarely used outside the STC because of data quality issues. To improve VDOT's traffic data collection practices, the following actions are recommended: 1.) VDOT's Operations Management Division should initiate a data quality assessment program. 2.) VDOT's Operations Management Division should identify and allocate dedicated funding for maintenance of all traffic data collection sites. 3.) The Northern Virginia and Hampton Roads STCs should identify those detector stations in each region that provide critical data and discontinue maintenance of the remaining stations. 4.) In Staunton, Salem, and Richmond, where STCs have been established but extensive deployment of sensors to obtain volume, occupancy, and speed has not yet occurred, deployment of such sensors should be limited to no more than one station between each interchange. 5.) VDOT's Operations Management Division should proceed with obtaining travel time data for freeways and primary arterials. 6.) VDOT's Operations Management Division in consultation with the Information Technology Applications Division should establish a common format for archiving data such that data can be shared across work units and applications. Where possible, data should be stored at the lowest level of aggregation possible so that they can be applied to the greatest number of uses.