Memorial Day weekend unofficially marks the start of summer. It also marks the unofficial start of holiday traffic snarls on Interstate 17.
Northbound traffic tends to get heavy on the edges of the Valley at the start of holiday weekends, as Phoenix-area residents head for cooler climates. Southbound traffic then backs up at the end of the long weekends, when those travelers are heading home.
Any accident or breakdown can lead to lengthy backups and delays.
But a $522 million, three-year project by the Arizona Department of Transportation is aimed at reducing some of those dreaded delays. The work covers a 23-mile stretch of freeway north of the Valley, from Anthem Way to Sunset Point. That section of I-17 sees about a million travelers a year.
For two years, construction crews have been blasting, scraping and shaping the hills and mountains to widen the route. Crews are laying multiple layers of asphalt and pavement on the southernmost section of the project, which will add a lane in each direction.
“The last layer will go down in fall of 2024, and so the timeline for that 15 miles to open is roughly by the end of 2024,” said ADOT’s Laura Douglas.
North of that 15-mile stretch will be a first-of-its-kind system in Arizona, featuring 8 miles of flex or reversible lanes. The flex lanes will carry northbound traffic most of the time, including the start of weekends, when many Valley residents head north. Then at the end of the weekend, with more traffic headed back to Phoenix, the lanes will be reversed to handle the southbound traffic.
“It's going to be a highly technological corridor, in terms of cameras, gates, a net barrier to ensure that nobody enters the flex lanes in the wrong direction,” Douglas said.
“There's going to be a significant amount of time to clear traffic out of the flex lanes, make sure that everything is safe before it is switched in the opposite direction,” she added. “So there's not going to be stragglers within those flex lanes. That’s important to note.”
Coordinating all this work from a construction trailer just off I-17 is Annette Riley, the project manager.
She says the biggest challenge happened shortly after it was approved in 2021, when federal regulations for waterways changed. The preliminary plan required permits for four crossings over washes.
“But because of that law change, we went from four to all the dry, ephemeral, seasonal washes, so a total of 94,” Riley said. “So that was a huge challenge and a huge lift for the project team.”
Those changes had to be worked out between ADOT and contractors in the middle of the COVID outbreak, which meant fewer face-to-face meetings.
Despite those early obstacles, the project is still on schedule. Riley says 300 contractors and ADOT staff are working every day except holidays, when they stop to avoid adding to traffic delays.
So far, about 1.8 million cubic yards of earth have been moved, in some cases off mountain sides to fill in other areas where the freeway lanes are being added. Ten bridges have been widened, and two others have been replaced.
Some of the original sections of I-17 are close to 70 years old. Riley says construction standards from the 1950s and ’60s are significantly different from 21st century guidelines. That was a problem with the small tunnels that go under the freeway to divert water.
“Based on old standards and details, it could not accommodate additional loading, additional weight on top of those box culverts,” Riley said.
That led to another first-of-its-kind application in Arizona, using a lightweight aggregate around those culverts.
“We're using this product called recycled foam glass, lightweight material on this job, extensively to address that,” Riley said.
She says engineers and crews are also taking care to preserve and restore as much of the desert and the vegetation that's been moved.
Anyone who has traveled l-17 is familiar with the Rock Springs Café just north of the Maricopa County line. It's known for its pies and pastries.
“We have probably, most likely, the best pies you can buy, and probably the second-best pie you've ever had in your life,” said cafe manager Roger Vore. “Only one that ever beats it would be your grandmother’s.”
Vore says motorists stuck in traffic jams often end up at the cafe.
“It depends on the location of the stoppage, but if people can get to us, they would rather stop off here, possibly go to the bathroom, possibly get a piece of pie, possibly stop and eat.”
Vore says construction has not hurt business, but he’s looking forward to the completion of a project he says is long overdue.
ADOT hopes that by the summer of 2025, construction will be completed and traffic will be flowing on all lanes of the busy freeway.
