Dana Alvidrez

Dana Alvidrez, city transportation engineer, said she and motorists are lucky to have a staff that can re-time traffic signals to improve traffic flow.  (David Minton/Staff Photographer)

The City of Chandler was part of a pilot program to look at how artificial intelligence might improve traffic flow.

Their conclusion: There was a slight benefit to using AI, but not enough to justify the cost.

“We are lucky in Chandler in that we have a good staff,” said the city’s traffic engineer, Dana Alvidrez. “We do have the capability that we get to retime our signals frequently, and we have the expertise to do that. Not all jurisdictions have that.”

She said there was some benefits in the adaptive signal pilot program the city was part of.

“It came back that there might be slight improvements that we could make, here and there, in the 2-5% range as far as delays, but as far as the cost of the system vs. the improvements that it got, we decided it was not necessarily for us.”

Alvidrez said, however, it would be ideal for other jurisdictions that don’t have the staff or expertise to adjust their signals on a regular basis. She added that this technology is still new and improving, and this is something they may want to revisit in the future after improvements are made.

She said currently they change the timing on lights in one section of the city every year and that they are currently able to retime lights to optimize traffic flow at least every three years.

Another new program that Alvidrez said the city is starting to look at is V2I, or vehicle-to-infrastructure. This is where a car can communicate directly with traffic infrastructure, such as at an intersection.

Alvidrez says it is limited now, only a few luxury brand cars have the capabilities to use it. And most of the information being transmitted is from the infrastructure to the car.

For example, using a predictive algorithm, it could tell the driver how fast they could travel to stay within the speed limit and also make the next five lights. If there was an accident or heavy traffic ahead, they could alert a driver so they could take a detour and avoid that.

“Basically, they take our data from the signal system and then they do some sort of prediction algorithm to figure out what they think the signal will be and when it will change, based on some history. It’s a learning process for their system.”

Right now, the city’s traffic department is focused on how the area next to the SanTan Mountain Casino is expected to change when it opens in two years.

“It’s something we’re actively looking at,” Alvidrez said. “It’s something we’re getting a lot of questions about right now.”

The city has been upgrading its cameras at intersections. The new cameras can identify not only cars, but also bicycles. She said hopefully they will be able to identify pedestrians in the future, but that we’re not there yet.

In the past, glare would make it hard to know if there was a bicycle or pedestrian crossing the street. If they do know they are there, they can extend the time a light is red to allow them to get across safely without them having to get off their bike to push the button, Alvidrez said.

Technology is also changing quickly. In the future, they may be planning traffic for a world where autonomous cars dominate the roads.

“As soon as you think you got it figured out, something else changes and we get to do it all over again,” Alvidrez said. “It’s definitely an ongoing process.”

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