The capacity of a roadway to serve motor vehicles is determined primarily by constraints that are present at intersections. Vehicles turning to and from the primary roadway at unsignalized intersections cause through vehicles to stop or slow, thereby influencing traffic flow and affecting the level of service. The available green time at signalized intersections for any given traffic movement is substantially less than would be available for free-flow operations. Therefore,

it is important to analyze and characterize the combined effects of geometry and traffic control proposed for the design of an intersection.

Refer to the and the for additional information and operational analysis techniques for intersections.