Signal Timing - Basic Timing Functions

Basic Timing Functions

There are several basic timing functions that need to be programmed for the traffic controller to operate.

MIN time determines the minimum duration of the green interval for each movement. Left turns, minor streets, major streets, usually have different MIN times. Left turns and minor side street intervals are often in the range from 4 to 10 seconds while major streets often go higher than 15.

Gap, extension, or passage time determines the extendable portion of the green time for a movement. The movement remains in the extendable portion as long as an actuation is present and the passage timer has not expired. If the interval is set as three seconds and there is not vehicle present after that three seconds, the movement will terminate.

MAX time limits the maximum time of the green interval. If there are no conflicting demands on the intersection, the controller will ignore the MAX and rest in the major street movement.

Yellow Clearance determines the yellow time for the associated movement.

Red Clearance determines the all-red time for the associated movement.

Walk time provides the length of the walk indication.

Flashing Don't Walk is the duration of the flashing pedestrian clearance. This is timed as the length of the crosswalk divided by a speed of 3.5 feet per second.