Final Report on Analysis of Corridor Delay Under SCATS Control (Orchard Lake Road Corridor)

This study was designed to determine the change in travel time following the implementation of the Sydney Coordinated Adaptive Traffic System (SCATS) in Oakland County, Michigan. A before/after comparison was used to examine the change in travel time on a specific corridor (Orchard Lake Road). The results of the study showed that corridor travel-time and intersection delay for the main street through traffic improved as a result of SCATS implementation. The corridor travel-time improved for both directions for both the peak and the non-peak periods. The reduction in corridor travel time ranged from 6.56% to 31.80%, with savings in travel time being higher during the non-peak periods. Before/after intersection delay studies showed that both stopped and approach delay decreased for the main street through traffic at the intersections as a result of SCATS implementation. The reduction in delay and travel time is attributable to the increase in green time for the main street traffic under SCATS control. SCATS extended the green time for the main street through traffic, reducing the average degree of saturation from 1.02 to 0.87 during the peak periods and from 0.73 to 0.56 during the non-peak periods. SCATS reduced the green time for other approaches increasing the degree of saturation on the minor street through traffic from 0.86 to 0.95 during the peak periods and from 0.42 to 0.51 during the non-peak periods. SCATS allocated the green time effectively, especially during the non-peak periods. The system utilized the excessive green allocated for the minor street by reassigning it to the main street traffic. Extending the green time contributed to the reduction in delay in many ways. It reduced the degree of saturation, reduced the red time for the main traffic, and provided a wider through bandwidth for the main traffic along the corridor. In oversaturation cases, extending the green time often eliminated the number of vehicles that had to stop for more than one cycle. A Before/after offset study showed that the through bandwidth increased during all time periods for both directions, mainly as a result of extending the green time for the main street traffic.

  • Record URL:
  • Corporate Authors:

    Michigan State University, East Lansing

    Department of Civil and Environmental Engineering
    3546 Engineering Building
    East Lansing, MI  United States  48824-1226

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    Michigan Department of Transportation

    State Transportation Building, 425 West Ottawa Street, P.O. Box 30050
    Lansing, MI  United States  48909
  • Authors:
    • Taylor, William C
    • Abdel-Rahim, Ahmed S
  • Publication Date: 1998-4


  • English

Media Info

  • Media Type: Web
  • Features: Figures; References; Tables;
  • Pagination: 116p

Subject/Index Terms

Filing Info

  • Accession Number: 01144496
  • Record Type: Publication
  • Created Date: Nov 13 2009 1:33PM