Changes to signal timing mean big benefits for Phoenix drivers

ADOT, Phoenix engineers make improvements on two busy roads crossing I-17

PHOENIX ‒ It may not be surprising to hear that coordinating the timing of city traffic signals and those at two busy Interstate 17 interchanges will save drivers time.

But the Arizona Department of Transportation and its partners, the city of Phoenix and Maricopa Association of Governments, have taken it a step further by adding up the time saved and its dollar value for a project involving Camelback and Indian School roads.

The answer: Motorists are expected to save 350,000 hours of travel time, worth $6.2 million, per year.

“Continuous improvement is ADOT’s culture and is reflected in both large and small things that the ADOT team does every day. Sometimes a seemingly small change that makes better use of resources can mean big improvements,” ADOT Director John Halikowski said. “Drivers are already seeing a time savings from this coordination. Saving time means saving money and more time with family, friends and things you enjoy doing.”

“The ADOT team’s challenge is to keep improving time savings and promote efficiency for Arizona’s taxpayers,” Halikowski added.

“When ADOT, MAG and the city of Phoenix work together strategically, the public is the beneficiary,” Phoenix Mayor Greg Stanton said. “Properly timing the traffic signals at these busy intersections will ease congestion, which gets commuters home sooner, saves fuel and keeps our air cleaner.”

A project funded by Maricopa Association of Governments’ Traffic Signal Optimization Program studied traffic signal timing at the Camelback and Indian School interchanges and nearby city streets and recommended a number of improvements. The project developed a common cycle length for all traffic signals near those interchanges and the best timing for the morning and evening commutes.

ADOT and Phoenix made these recommended changes, leading to significant improvements in travel times at these locations. An independent study by ADOT staff identified the benefits in time saved.  

Besides saving motorists time, these adjustments are expected to improve safety by reducing the number of stops drivers must make and time spent waiting at traffic lights. Shorter travel times and fewer stops also reduce fuel consumption and air pollution. 

ADOT and Phoenix continue to evaluate other I-17 corridor interchanges to see if changes in signal coordination can improve traffic flow elsewhere.