Adaptive Signal Control/ACS Lite

Adaptive Signal Control Technologies (ASCT) is a part of FHWA's Every Day Counts (EDC) Initiatives. ASCT measure traffic flow in real-time and automatically adjust signal timing to promote smooth flow of traffic along arterial streets. These adjustments are made in real-time to improve travel-time reliability to produce smoother flow by reducing congestion and delay.  MDOT is deploying an ASCT system known as Adaptive Control Software Lite (ACS-Lite) on two corridors as part of the EDC initiative.  ACS-Lite is just one example of an adaptive signal control technology.  ACS-Lite was specifically designed to be deployed using conventional control equipment, communications and traffic sensors on arterial streets, making it a more cost-effective alternative to other signal timing adjustment technologies. The expected outcome is for Michigan to embrace this technology and move ASCT in general into standard practice.  The two corridor deployments by MDOT are on West Saginaw in Lansing and on M-84/Bay Road in Saginaw.

Project Examples:

  • As mentioned above, MDOT is deploying two ASC-Lite systems as part of the Every Day Counts Initiative.
    •  Project status

West Saginaw in Lansing has been operational since early March, 2012.

M-84/Bay Road in Saginaw is under construction and expected to be operational by December, 2012.


In addition to MDOT, other agencies in Michigan that are currently using or pursuing the use of ASCT are:

  • The Road Commission for Oakland County began deploying an ASCT System known as SCATS (Sydney Coordinated Adaptive Traffic System) in 1991 and currently approximately 700 signals, well over half of the 1200 signals that they control, are fully adaptive.
  • The city of Ann Arbor began deploying an ASCT System known as SCOOT (Split Cycle Offset Optimization Technique) in 2004 and currently have 44 intersections on Plymouth Road, Washtenaw Avenue and Eisenhower/Packard under fully adaptive control.
  • Genesee County Road Commission has deployed an ASCT System known as InSync at seven Intersections on Holly Road near the interchange with I-75 near Grand Blanc.


Related Links



Paula Corlett, Traffic Signals Engineer at MDOT,, or
Morrie Hoevel, Mobility Program Engineer at FHWA,