Turning movement count

A turning movement count or TMC is a type of traffic count that counts the flows of people and vehicles through an intersection. As with other traffic counts, they may be conducted on either a temporary or permanent basis and may use a variety of different technologies such as recorded video processed with image recognition algorithms or manual field collection assisted by tools like turning movement counters.

Classifications

TMCs may classify different users of the intersection and provide separate counts for each. For example a TMC could provide separate movement counts for trucks, buses, other motor vehicles, cyclists, and pedestrians.

Pedestrians, who don't use turning lanes in the roadway, may be counted differently such as when they cross the street in marked or unmarked crossings.

Applications

TMC's may be used to determine whether the intersection needs a traffic light. Formulas are used to decide whether the volume of the traffic determines that a light is needed. This equation is based on the road classification, entering speed and pedestrian/bicyclist movement through the intersection. A total of eight hours of turning movement is generally mandated for this type of assessment.