Knowledge Base

Very few of the traffic signals in Jefferson County are constantly run in “free” mode, meaning they are not coordinated with other signals. When a signal runs in free mode, it does not have to maintain timings that keep it in coordination with adjacent signals, therefore it can quickly change in order to give the green light to a vehicle that has approached and stopped at a red light. Free operation is efficient at locations that have very low volumes, are not near any other traffic signals, or have other unique conditions. Although most of the traffic signals in the county run coordinated during the day, they switch to free operations during the overnight hours when traffic volumes are very low.