How does the county decide when a traffic signal should be installed? Will a traffic signal reduce accidents at an intersection?

Traffic engineers follow the national standards described in the Manual on Uniform Traffic Control Devices (MUTCD). The MUTCD mandates that a traffic signal cannot be installed unless the intersection has met the requirements of one or more traffic signal “warrants.” These warrants consider various criteria when evaluating the intersection, such as vehicle volumes, pedestrian volumes, and crash history.

Traffic signals can improve traffic flow and increase safety when used properly. However, traffic signals are not always the right solution and do not always prevent accidents. For example, a traffic signal may reduce the number of right-angle collisions at an intersection, but the number of rear-end crashes may increase.

To request that an intersection be evaluated for traffic signal control, please contact Transportation and Engineering.

Show All Answers

1. What do I do when I see a dark or flashing traffic signal?
2. What happens to Jefferson County traffic signals when they lose power?
3. Who regulates traffic in Jefferson County?
4. Who builds and maintains traffic signals in Jefferson County?
5. How do traffic signals work?
6. Who maintains flashing school zone beacons?
7. How does the county decide when a traffic signal should be installed? Will a traffic signal reduce accidents at an intersection?
8. What is the purpose of cameras at signalized intersections?
9. Are traffic signals in Jefferson County coordinated to reduce or eliminate the need to stop at red lights?
10. Once a driver turns onto a street where the traffic signals are coordinated, is it correct that the driver should not have to stop?
11. Do any traffic signals not run in coordination with other traffic signals?
12. Why is there a “Walk” symbol when no pedestrians are present?
13. How do signals for pedestrians work?
14. Why do I have to wait so long to get a green light or a “Walk” signal?
15. Do emergency vehicles get priority at signalized intersections in Jefferson County?
16. Is it possible for two conflicting directions of traffic at a signalized intersection to receive green lights at the same time?
17. How does a flashing yellow left-turn arrow work?