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Aerial view of paving operations

Traffic signals

Traffic signals promote safe, convenient, and efficient travel on Macomb County roadways.

23 Mile Road mast arm traffic signal at intersection.

Traffic signals play an important role in the modern road system. When used properly, traffic signals facilitate safe, convenient, and efficient travel by reducing certain types of crashes and minimizing unnecessary delays to users.

The Department of Roads takes a comprehensive and strategic approach to traffic operations, applying objective criteria, sound engineering, and safety principles to manage and implement appropriate traffic measures on Macomb County’s transportation network.

MCDR follows well-established and nationally recognized guidelines to determine when and where traffic signals are necessary. These guidelines identify specific traffic and pedestrian volume thresholds, incident history, sight distance, and any unusual conditions that may exist at an intersection.

To determine if a traffic signal is needed, a traffic study is completed before a traffic signal is approved and designed. Traffic signal studies consider a number of important factors, including:

  • Intersection design, crash history, and potential
  • Vehicle traffic volumes and gaps in traffic approaching the intersection 
  • Approach speeds, sight distances, and locations of nearby signals
  • Characteristics of the area and adjacent land use
  • Projected and planned growth

Traffic signals are valuable devices for the control of vehicle and pedestrian traffic. When properly located and operated, traffic signals:

  • Provide the orderly movement of traffic.
  • Increase the traffic handling capacity of an intersection, where proper physical layouts and control measures are used.
  • Can provide continuous or nearly continuous movement of traffic at a defined speed along a given route, under favorable conditions.
  • Can be used to interrupt heavy traffic to permit other traffic, vehicular or pedestrian, to cross.

While traffic signals can reduce the number of collisions at an intersection, traffic signals can also cause an increase in other types of crashes when not used properly. Improper or unwarranted traffic signals can result in:

  • Excessive delays, resulting in significant fuel waste and higher costs to motorists.
  • Disobedience of traffic signal indications and other traffic control devices.
  • The use of less adequate routes by motorists in an attempt to avoid such signals.
  • Increased accident frequency.

The Department of Roads often receives requests to install traffic signals. Although the public is encouraged to notify public officials with what they perceive to be traffic concerns, traffic signals are not installed based on casual observations or uninformed opinions. Public agencies have a responsibility to manage and install traffic signals based on well-established and nationally recognized guidelines as well as traffic engineering studies.

If a traffic study shows that a traffic signal is justified, traffic engineers complete multiple tasks to allow for the proper planning, design, and installation of traffic signal equipment.

If you have further questions related to traffic signals in Macomb County, please contact the Department of Roads at or 586-463-8671.

Please note: In order for intersections to operate properly, many new traffic signals require other physical changes to be made to the intersection, including new traffic signs and pavement markings.