Why can't the signals be timed together to reduce delay?

All traffic signals in Woodbury rely on detectors to maximize efficiency. Traffic signals typically will not turn red for the main roadway until the detectors sense a gap in the traffic and a vehicle is detected on the cross street, or the maximum time for a green light is reached. This is designed to increase efficiency and safety by reducing the number of vehicles confronted with a yellow light.

Unfortunately, gaps in traffic often occur when a large platoon of traffic is approaching but is out of range of the detectors. This causes the entire platoon of vehicles to arrive at a red light, sometimes for the benefit of just a few vehicles entering from the side street.

Traffic signal systems can be coordinated, but doing so will typically lead to longer wait times for side street traffic and for left turns. When traffic signals are coordinated they operate on a fixed timing cycle to remain in step with each other. The cycle must be long enough to accommodate the busiest intersection in the corridor. While this coordination can be a benefit, it is costly to implement and will typically increase the wait time to enter a highway. These coordinated timing cycles also benefit from regular adjustments and maintenance, which can be costly to optimize efficiency.

Show All Answers

1. How do traffic signals work?
2. How much do traffic signals cost?
3. Will a traffic signal make an intersection safer?
4. How does the City decide where to install signals?
5. Why is the "Walk" light so short? I can only get halfway across before it starts flashing.
6. Why can't the signals be timed together to reduce delay?
7. What should drivers do when a traffic signal is flashing or all lights are dark?
8. How should drivers respond to a flashing yellow arrow?
9. Which government agency owns which traffic signals?