Most Jefferson County traffic signals are programmed based on the time of day, the location, traffic patterns, and traffic volumes. There are many factors that can affect the design of timing plans, such as the volume of traffic on the side streets, the crossing time required for pedestrians, the distance between traffic signals, the speed limit on the main street, the total overall traffic volume, the number of turning vehicles, and the number of lanes available for each movement of traffic.
Most of Jefferson County’s traffic signals operate on three different timing plans, which include weekday AM Peak, PM Peak, and Off-Peak plans. There are also special plans for weekends. There are also some timing plans implemented for unique circumstances, like school traffic, heavy lunchtime traffic, or holiday shopping traffic.
There are numerous factors that can impact the effectiveness of traffic flow that unfortunately cannot be accounted for in the traffic signal’s programming, such as the actual speed of traffic, the acceleration patterns of motorists, variations in the volume of traffic during the timing plan, the frequency of emergency vehicle pre-emption, and the frequency of pedestrians (having pushed the button to cross) each cycle.