DES MOINES, Iowa — The City of Des Moines is working to retime more than 425 traffic signals.
John Davis, the city's traffic engineer, said the project analyzes the signals to see if they stay on any one color too long or not long enough. He said this process hasn't been done in around 25 years.
The project also looks at lights in a comprehensive sense, meaning how the timing of various signals on the same street impacts drivers.
Davis said it's important to do this now because of how much the city has grown over the years.
"Other areas have changed in their land uses and we want to document those changes in volumes, and then reapportion or reallocate the amount of green time that's at each signal so that we have smoother traffic flows," Davis said.
Working to get smoother traffic flows will not just benefit drivers, but also impact bikers and pedestrians.
"It's safety," Davis said. We're making sure that our signal timings are in accordance with current standards for walk times... Things that may have changed over the years."
He said these adjustments help the city's efforts to have a more walkable and bikeable transportation network.
This project is divided into five phases. The first phase wrapped up in 2019, but the remaining phases were paused when the pandemic hit. The city has now resumed progress and is currently working on phases two and three.
Phase two is expected to be completed by the end of the year, with phase three set to finish in the middle of 2022.
Davis said phase four should also be starting soon, and the city is working to get grants to fund it. It's expected to be completed by the end of 2022. The final phase should wrap up in 2023.
Davis said more efficient timing could also bring another benefit—better air quality.
"We don't have any unused green time," Davis said. "Undo the delay and that equates to less pollutants in the air because of fuel emissions."
This project is expected to cost around $1.3 million.
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