Frequently Asked Questions

Why is signal synchronization needed?

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Drivers often get frustrated when they have to stop at successive traffic lights, or when they have to wait a long time for a green light, especially when there appears to be no traffic in the other directions. Traffic signals are designed to distribute the green time to conflicting traffic streams, generally based on the traffic volumes. If the traffic on a main street is considerably higher than the side street, more green time may be given to the main street which could result in a longer wait for drivers on the side street. However, synchronizing signals along a main street can benefit all motorists because once a vehicle enters the main street, it may continue with minimal stopping. Hence, it is beneficial for both the main street and side street traffic. The goal of synchronization is to get the greatest number of vehicles through the intersections with the fewest stops.

 

How does traffic signal synchronization work?

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The way traffic signal synchronization works is by calculating the arrival time for a group of vehicles at each intersection traveling at a specified speed, and then the traffic signals are strategically timed to turn green just as the group of vehicles arrive at each intersection. In order for the traffic signals to be synchronized, a group of signals must all be set to run on the same cycle length (the amount of time it takes for the signal to go from green to yellow to red; and back to green again - after the cross street has been serviced.

 

What is the Green Band?

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The green band is a roughly 30 second window where motorists would see green lights along a corridor. Travel faster than the green band and you rush to a red light. The green band is typically set around the posted speed limit.

 

What is the best way to get through the most signals without stopping?

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Keep your speed at or slightly below the speed limit and you will have a far better chance of arriving at intersections with a green light. If you drive too slow or too fast, you will be outside the green band and will see more red lights.

 

Why don’t I make it through all the lights even if I drive the speed limit?

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Crossing other major roadways can make it difficult to provide a green light at every signal. Other challenges to synchronization include unevenly spaced signals, freeway crossings, variations in left-turn volumes, and travel through other cities.

 

Which traffic signals are synchronized?

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CV Sync- Phase 1 will synchronize signals across jurisdictions on Highway 111, Ramon Road and Washington Street.  Additional corridors will be synchronized with future phases of the CV Sync project

 

What time of day are signals synchronized?

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This can vary depending on the street and other traffic factors, but generally signals are synchronized on weekdays in the morning and afternoon rush hour. Additional synchronization for other time periods will be developed over time and for special events with coordinated messaging on Changeable Message Signs which are being installed with the project.  Traffic flows will be actively monitored and timing will be adjusted over time to improve signal operations.

 

How do traffic signal synchronization projects get funded?

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CV Sync- Phase 1 is funded through a combination of local, State and Federal funding coordinated through the Coachella Valley Association of Governments (CVAG).  This regional approach, coordinated through CVAG allows more effective and efficient expenditure of funds and implementation.  This leads to a consistent regional standard for equipment and software enabling interoperability and simplified maintenance.  This approach also allows for coordination across jurisdictional boundaries.