Q&AZ: How are traffic lights controlled across metro Phoenix?

Does it always seem like traffic lights are slowest when you're in a hurry? While your drive to work may look the same, it certainly isn’t timed the same.

A listener asked: How are traffic lights controlled across metro Phoenix?

In an effort to keep traffic running smoothly, Phoenix adjusts signals using fixed time and various detection technology.

Simon Ramos, traffic engineering supervisor with Phoenix's Street Transportation Department, said one of the devices used to track vehicles is inductive ground loops.

“You’ll see some, say, cuts in the pavement, or you’ll notice maybe a black square where a car will drive over," Ramos said. “And then that tells the traffic signal controller, which is at every one of these intersections, that there is a vehicle there.”

On a larger scale, traffic control operations across the Valley’s 27 cities and towns run under different commands. Those commands depend on arterial road data like, time of day, road congestion and pedestrian traffic.

Micah Henry, the ITS engineer for Mesa, said cities across the Valley collaborate often to optimize traffic control.

“We’re all using our counterparts and our adjacent cities to make sure we're flowing traffic seamlessly across our city borders,” Henry said. “Drivers aren’t usually aware of when they enter or leave city boundaries, and we want to make that as smooth as possible for the drivers.”

This communication between cities is important during high traffic events. Ramos says cities will communicate for big sporting events or concerts held in spaces like the State Farm Stadium in Glendale.