Arizona's I-17 Improvement Project is nearing completion, with $522 million allocated for upgrades between Anthem Way and Sunset Point. The project includes widening roadways, replacing bridges and constructing flex lanes. Key benefits include reducing congestion, improving safety and supporting economic growth. The project, a public-private partnership, is expected to be completed by the end of the year.
Arizona Department of Transportation photo
Crews lower a steel beam into place on a bridge over Interstate 17 in Arizona.
The Arizona Department of Transportation (ADOT) allocated approximately $522 million for the 23-mi. I-17 Improvement Project upgrading Interstate 17 between Anthem Way and Sunset Point that is expected to be completed by year's end.
The project includes widening 15 mi. of roadway; replacing two bridges and widening 10 others; and constructing approximately 8 mi. of flex lanes. Work began in September 2022, with project planning dating to 2018.
This is a public-private partnership (P3) project, with the Kiewit-Fann Joint Venture developer team operating and maintaining the flex lanes segments for three years following construction completion.
Key team members include Kiewit Infrastructure West Co., Fann Contracting Inc., Kiewit Engineering Group Inc., DBI Services LLC, CONSOR Engineers LLC dba Apex Design, T.Y. Lin International, Lee Engineering, Terracon Consultants Inc., Wheat Design Group Inc., Y2K Engineering and Pinyon Environmental Inc.
The project includes installing a flex lane system, which ADOT said is a "proven technology to alleviate traffic congestion during peak travel times, or if an unplanned incident creates delays."
The flex lanes operate as an additional two-lane roadway that carries one direction of traffic at a time and can alternate between northbound and southbound depending on the greatest need.
This project is being financed through state highway funds, an Infrastructure for Rebuilding America (INFRA) grant, Maricopa Association of Government programmed funds for the section in Maricopa County and additional federal aid to match state highway funds.
The project has multiple benefits, according to ADOT.
"The section of I-17 is one of the most heavily utilized roadways in Arizona, with more than 1 million travelers each year," according to the project website. "This project will reduce congestion, which helps to improve safety by creating more space between vehicles. With the addition of new travel lanes from Anthem Way to Black Canyon City and flex lanes from Black Canyon City to Sunset Point, capacity on I-17 will increase in both directions. This will better accommodate existing traffic and increased traffic as the demand on I-17 continues to grow."
The work also supports economic growth.
"Each year, more than $300 billion in goods are shipped to and from Arizona," according to the website. "I-17 is identified as one of the state's key commerce corridors moving people and goods between southern and northern Arizona. … This project will help make I-17 a more favorable route for commercial truck drivers who travel through the region and support our local businesses."
Project Segments
The project is divided into two segments.
For the Anthem Way to Black Canyon City section, crews are adding northbound and southbound lanes, which involves widening the northbound section on the median side and, for the southbound section, widening on the median side in some sections and on the outside in others.
For the Black Canyon City to Sunset Point (flex lanes) section, crews are constructing two flexible travel (flex) lanes alongside the existing southbound lanes of I-17, with the flex lanes separated from the southbound roadway by a concrete barrier.
Work is ongoing 24/7. Progress has been solid, with blasting completed last May. Approximately 177,000 cu. yds. of rock and material were removed for the new lane construction.
Twelve bridges along the project corridor are under construction; the bridge work is expected to be completed later this year.
The bridge work was extensive. For example, at the New River Road traffic interchange, crews set nine girders on each bridge during a two-night operation. Three sizes of girders were placed, with the largest weighing about 45,000 lbs. and the smallest weighing about 30,000 lbs.
Having a Blast
The project also prompted plenty of rock blasting.
Controlled rock blasting began in December 2022. Blasting activities required full closures of 1-17 for safety purposes.
The team conducted 62 blasts.
"That's far less than the initial estimate of 120 blasts," Annette Riley, ADOT's project manager, said. "In many circumstances, crews were instead able to ‘rip' or excavate rock in certain areas using heavy equipment. Ripping is the preferred method of rock removal because it lessens the impacts on traffic. Areas where the rock material was too hard to be ripped needed to be blasted instead."
Recycling the rock and material was crucial. It was removed during the blasting process and hauled to another area of the project to be reincorporated into the new roadway. Much of the blasted material was crushed, then used as aggregate base, embankment and rock mulch along the new lanes.
The earthwork and excavation removed 1.7 million cu. yds. of material from the mountainsides.
Reaching Goals
The JV has attained several milestones since construction began.
"We are approximately 85 percent complete," said Nik Hunter, the J-V's project manager. "We've completed major earthwork operations, which consisted of 2 million cubic yards of material. Most of our bridge widenings are complete, and we have two bridges that will be completed in the spring. We have the asphalt base pavement complete up to Segments 1 and 2. Right now, we are working on permanent erosion control throughout the project area. This includes entrenchment protection, riprap, paving and scour pads.
"We have over 45,000 linear ft. of cast-in-place barriers, and we've installed about 30,000 ft. so far," he added. "This is an ITS [intelligent transportation system] technology-driven project with CCTV cameras, message board displays and other components to be installed. All of our underground conduits for the ITS system have been installed. We have one more source for cold water. We started rolling fiber a few months ago, which is another project milestone. The display signs and other elements will be installed in the spring."
Crews still must place a 0.5-in. ACSC rubberized asphalt course to finalize the paving.
Hunter said the project has posed multiple challenges, including working alongside I-17.
"It is a major corridor in Arizona — it connects Phoenix up to Flagstaff and a major north-south transportation route," he said. "The high speeds of motorists make for dangerous conditions for the crews. You also have variable terrain in the project area — slopes, elevation changes and areas where the road winds and curves. One of the goals of the project is to make this corridor safer and ease congestion."
Riley stressed the importance of I-17 to commuters and commercial traffic, and the connections provided by I-40.
"This is pretty much the only high-speed connection for northern Arizona to the southern part," said Riley, who noted that the "terrain is severe."
Utilities Factor
Riley stressed that extensive utility work has not impacted the schedule.
"We have been able to work out solutions with the utilities," she said. "There is a Kinder Morgan gas pipeline that was going to be impacted, but we were able to work through by negotiations."
Another utilities challenge was to successfully arrange a connection for the ITS systems to the electrical grid.
As with other construction projects, this one required water and, with Arizona having a tight water supply, arrangements were made.
"Construction water was in high demand," Riley said. "The city of Black Canyon is in the area, and they were very concerned about the amount of water being used, along with the sources of the water, especially with the drought's conditions over the past few years and the state of the aquifers."
Hunter said the JV sought alternative water sources to alleviate the concerns of Black Canyon residents.
"We were able to diversify our resources, and we found an alternative source in the south end of the job," he said.
Road construction took place within Black Canyon and other towns in the corridor.
Major earthwork operations, especially at night, resulted in a fair amount of heavy truck traffic to remove the debris and the material generated.
"There were nights when we had 20 to 25 haul trucks, and we accomplished this with single-lane closures of the freeway," said Hunter. "This helped us manage the later earthwork operations on a tight and limited access project."
Meantime, when construction began, ADOT undertook action to protect native plants and landscapes along the corridor. Crews removed native vegetation, including sag-uaros, palo verde trees and ocotillos and brought them to temporary nurseries for later replanting.
The work area will be replanted with native seed mixes and nursery-grown plants.
New Materials
Finally, the project incorporated foam glass aggregate as a new construction material. Foam glass is made by crushing recycled glass into a powder and mixing it with a foaming agent. The mixed powder is then sent through a kiln and softened.
"Bags are filled with Ultra-Lightweight Foam Glass Aggregate," wrote Laura Douglas, an ADOT spokesperson. "This unique material, which is made from 100 percent recycled glass, is being used at 19 locations throughout the project corridor.
"Because this is a strong, lightweight and waterproof material, the foam glass will be used primarily to help strengthen the existing box culverts, which are concrete structures designed to channel water. The culverts were originally designed to withstand the weight of a two-lane roadway. The foam glass is used as fill material to support the weight of the additional lanes along the 23-mile stretch of I-17." CEG
Irwin Rapoport
A journalist who started his career at a weekly community newspaper, Irwin Rapoport has written about construction and architecture for more than 15 years, as well as a variety of other subjects, such as recycling, environmental issues, business supply chains, property development, pulp and paper, agriculture, solar power and energy, and education. Getting the story right and illustrating the hard work and professionalism that goes into completing road, bridge, and building projects is important to him. A key element of his construction articles is to provide readers with an opportunity to see how general contractors and departments of transportation complete their projects and address challenges so that lessons learned can be shared with a wider audience.
Rapoport has a BA in History and a Minor in Political Science from Concordia University. His hobbies include hiking, birding, cycling, reading, going to concerts and plays, hanging out with friends and family, and architecture. He is keen to one day write an MA thesis on military and economic planning by the Great Powers prior to the start of the First World War.
Read more from Irwin Rapoport here.
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