The computerized system that regulates signals in Gaithersburg and Bethesda, Md., has produced generally less congestion and smoother traffic flow, according to the Montgomery County Department of Transportation. Satisfied by the results, the County's Division and Traffic Engineering plans to expand the system, at an estimated cost of $3 million, to include signals on all county roadways within the next three years. Hundreds of detectors embedded in the pavement along a 50-mile network of cables provide the computer constant monitoring of traffic volume and flow. The metal of passing vehicles changes the induction of the detector's wire loop, registering an impulse, or "count," through the network to the Division of Traffic Engineering computer in Rockville. The number of counts indicates the volume of traffic. By recording the duration of an induction change, the detector measures its own "occupancy," or traffic flow. A stopped vehicle would register a long occupancy to the computer that would then decrease occupancy by adjusting appropriate traffic signals to increase flow. Two types of detectors provide volume and flow measurement. Intersection detectors notify the local signal controller (the yellow box) at intersections of traffic congestion. The computer uses 10 to 12 sampling detectors to monitor traffic along stretch of roadway that could involve numerous signals. Sampling detectors reveal a larger picture of traffic volume and flow so the computer can synchronize a series of signals, preventing rush-hour backups on major arteries. (Author) backups on major arteries. (Author)

  • Corporate Authors:

    GCN Communications Corporation

    1G20 Elton Road
    Silver Spring, MD  United States  20903
  • Authors:
    • Hager, P
  • Publication Date: 1985-7-5

Media Info

  • Pagination: p. 17
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00396698
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 25 2004 2:37AM