Several projects on the state highway system were completed in 2021, while significant progress was made on other Arizona Department of Transportation jobs. As one year leads into a new one, ADOT provides “highway highlights” as part of its year in review.

Metro Phoenix Region

• Loop 101 (Pima Freeway) Improvement Project between Interstate 17 and Princess Drive. New lanes were opened in each direction during 2021 along 13 miles of the Pima Freeway in the North Valley. The project has resulted in improved traffic flow and interchange capacity enhancements that include reconstructed ramps and several widened bridges. The $185 million project will be completed this month when crews finalize permanent lane striping.


• Reconstructed Interstate 17 bridge over Central Avenue. As part of a $13.5 million project, ADOT has replaced the old bridge south of Downtown Phoenix with a wider structure that will accommodate future regional plans for additional lanes along I-17. Work was completed in October on the modern bridge that also provides increased clearance for Valley Metro’s under-construction South Central Avenue light-rail line.


• Loop 303 widening project between Happy Valley and Lake Pleasant parkways. Crews added new third lanes in each direction during 2021 along Loop 303 while also building several bridges to allow freeway traffic to be switched from temporary routes along the outside of the corridor to permanent mainline lanes. The $20.3 million project also added a new Loop 303 interchange at Jomax Parkway, which is scheduled to open soon when the city of Peoria completes the parkway between Vistancia Boulevard and the freeway.


• I-10 Broadway Curve Improvement Project between I-17 and Loop 202 (Santan/South Mountain freeways). ADOT launched work on its largest urban freeway reconstruction project in summer 2021. As part of this $776 million project, crews will add new lanes, construct new Collector-Distributor roads, build and widen bridges and dramatically improve ramp connections between I-10 and State Route 143 near Phoenix Sky Harbor International Airport. Completion is scheduled in late 2024.

Southern/Central Arizona


• I-10 Interchange Reconstruction at Ruthrauff Road in Tucson. This $129 million project, completed in October, included new bridge structures to carry Ruthrauff Road/El Camino del Cerro over both I-10 and the adjacent railroad tracks, eliminating the need for traffic to stop at a railroad crossing. I-10 also was reconstructed and widened by one lane in each direction in the area.


• New U.S. 60 Bridge over Pinto Creek. The new bridge on the only route between Superior and the Globe-Miami area was opened in September as part of a $22.7 million project that started in 2019. The new structure, which replaced a 72-year-old bridge, features 8-foot-wide shoulders and can handle heavier loads.


• I-10 Interchange Reconstruction at Houghton Road. The upgraded Houghton Road interchange, opened in November as the first Diverging Diamond Interchange in southern Arizona. The design, which has grown in popularity across the country, improves traffic flow while reducing conflict points by allowing Houghton Road traffic to temporarily move to the left side of the crossing at I-10 and have direct access to freeway on-ramps without stopping at a traffic signal.


• Oracle Road (SR 77) Improvement Project between Miracle Mile and Calle Concordia. The $34 million project is resurfacing 10 miles of pavement on Oracle Road and Miracle Mile while also adding LED street lighting, signal and sidewalk improvements and other upgrades. While completion is scheduled in 2023, more than half of the resurfacing work is already finished.


• SR 189 (Mariposa Road) Improvement Project in Nogales. Completion is scheduled in early 2022 on flyover ramps to connect SR 189 with I-19 as part of the $134 million project, which will eliminate the need for commercial trucks to stop at as many as three traffic signals. The primary goal of the project is to dramatically improve the flow of international commerce traveling to or from the border with Mexico. 

Northern Arizona Region

• Rio de Flag Bridge Replacement Project. This Historic Route 66 bridge, located in front of Flagstaff City Hall, was replaced in its entirety in summer 2021 as part of a $4.9 million project. Crews used an accelerated construction method involving components that were precast off-site. That allowed the bridge to be demolished and replaced in less than a week, limiting impacts to summer traffic in the busy downtown area.


• Interstate 15 Bridge No. 1 Replacement. This challenging $56 million project was launched in 2021 in the Virgin River Gorge near the community of Littlefield in northwestern Arizona. Bridge work is balanced with efforts to limit traffic impacts on I-15. The project is scheduled for completion in 2024.


• Interstate 40 Bridge Replacements in the Flagstaff, Ash Fork areas. Crews made significant progress in 2021 on new bridges at the Business 40 Interchange in west Flagstaff and along I-40 at Pineveta Draw west of Ash Fork. A pavement improvement project on US 60 and SR 260 in the Show Low area also began. All these projects, currently in winter hiatus status, are scheduled for completion this year.


As ADOT looks ahead to a busy new year for construction and maintenance projects throughout Arizona, drivers are asked to focus on safety when approaching and traveling through work zones along state highways. Lives are on the line so please slow down, pay attention to signs, avoid distractions and stay alert for workers and equipment.