940.6 Traffic Signal Spacing
Appropriate signal spacing is needed to preserve efficient traffic flow and progression on urban arterial roadways; for instance, a quarter- or half-mile spacing allows traffic signals to be effectively interconnected and synchronized. Adequate spacing will also tend to reduce rear-end collisions and “stop and go” driving that increases congestion, delay and air pollution. In urban areas, these guidelines were developed to allow for smooth operations given a 90-second total traffic signal cycle length.
|Roadway Classification||In Current and Projected Urban Areas||In Rural Areas|
|Major, Freeway||Traffic signals not allowed||Traffic signals not allowed|
|Major, Non-Freeway||½ mile (2,640 ft.) – 1 mile (5,280 ft.)||See note below*|
|Minor||¼ mile (1,320 ft.) - ½ mile (2,640 ft.)||See note below*|
|* Rural traffic signals are generally isolated signals rather than signals placed in a progression along a route. Signals are to be placed at least 5,280 ft. apart because of high rural operating speeds.|