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Providing Bottleneck Status on Network of Highways via Decision Support System Website

The Decision Support System, DSS, is an interactive website and was developed to equip engineers with tools that can gauge performance of a network of toll roads. The DSS’s output includes all locations on the network that are bottlenecked at a given hour. In this study, 20 toll plazas are situated on three intersecting highways maintained by the Orlando Orange County Expressway Authority (OOCEA) in Orange County, Florida. Three tools available on the DSS are TNCC, SHAKER and the HCM worksheet for computing capacities of the highway segments. Input includes geometric characteristics on the network’s highway segments and traffic characteristics. Users may choose to use default characteristics from data collected on November 5, 2002, or users may modify these input values by creating scenarios or incidents on the network. For instance, a lane closing may create new bottlenecks. This study also demonstrates that the DSS could become dynamic and provide quick and accurate output when connected to a real time database that continuously changes every 30 seconds. Software was created that randomly generated new values for the traffic volumes and percent trucks on the network. The DSS uses the HCM worksheet to compute capacities for most segments. TNCC and SHAKER are algorithms that compute the capacities of the network’s segments containing toll collection facilities. Their output is an MOE called NQMT, No-Queue-Maximum-Throughput, in units of vehicles per hour, vph. Although the two models are based on different methodologies, the predicted NQMTs are very close in value. The DSS compares the computed segment capacities to the segments’ approach volumes. If the approach volume for a particular hour of the day exceeds the capacity, the segment is identified as a bottleneck on the network for that hour. Using ArcIMS, the DSS graphically displays the highway segments on ArcGIS maps that are color coded to indicate various degrees of bottleneck status: total bottlenecked, near-bottlenecked, potentially bottlenecked or not bottlenecked at all. The DSS also provides a summary table displaying the number of segments in each category, thus providing engineers with a real time assessment tool for the entire network for each hour of the day.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 14p
  • Monograph Title: TRB 85th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01031517
  • Record Type: Publication
  • Report/Paper Numbers: 06-0595
  • Files: TRIS, TRB
  • Created Date: Aug 23 2006 2:15PM