How Arizona’s Highways are Built

Civil engineering contractor in Phoenix
Photo Credit: Arizona Department of Transportation (ADOT)

If you have driven along Interstate 10 anytime in the past two years, you have probably noticed many changes, mainly centered around Pecos Rd. in the east valley and 59th Ave. in the west valley. These changes are part of the Loop 202/South Mountain Freeway. The Loop 202/South Mountain Freeway, Arizona’s largest single highway project, picks up where other Loop 202/Santan Freeway construction left off. The 22-mile expansion is designed to provide commuters with a much-needed alternative to I-10 and is scheduled to open to the public in early 2020.

Did you know? The Loop 202/South Mountain Freeway is the largest P3 project in ADOT history. P3 projects are Public-Private-Partnerships = PPP or P³. Also, this P3 project is uniquely a design, construction, operation, and maintenance contract. By contrast, many P3 projects may only be design and construction.

Over the past two years, “crews have installed 20 miles of drainage pipe, laid 107,000 tons of asphalt pavement, and moved 9.9 million cubic yards of dirt.” An additional 10,800 tons of steel rebar, along with shotcrete, was used to construct overpasses and noise barriers. That is according to the Arizona Department of Transportation (ADOT).

Arizona motorists have had to follow what ADOT calls the three S’s: Speed, space, and stress. Speed restrictions remain in effect along Pecos Road and 59th Avenue. Capping the speed at 40 MPH, along Pecos Road, is crucial. It significantly reduces accidents in construction zones, ensuring workers, drivers, and pedestrians make it home at the end of the night. Essentially, where there is road construction, there is an increased need for motorists to slow down and keep their eyes on the road.

Remember: Arizona is now a hands-free state, too.

Here is a brief overview of how Arizona’s highways are built.

#1. The Planning Phase

Time to Completion: One to 24 months

The Arizona Department of Transportation collects and maintains an extensive quantity of data about Arizona’s streets, roads, and highways. Using all available data, surveyors, engineers, and other transportation experts work together to discover areas most in need of new infrastructure funding. Equally, all collected information is used for the preservation of roads, ensuring minor problems do not develop into major ones. The aim of new projects, like the Loop 202/South Mountain Freeway, is to mitigate traffic congestion and accidents.

#2. The Design Phase

Time to Completion: One to 30 months

The land is thoroughly surveyed using state-of-the-art equipment in phase two. Many factors, including location, terrain and soil properties, anticipated traffic volume, and more are also considered. After early land surveying, ADOT advertises and subsequently hires a civil engineering contractor in Phoenix to move the project forward. Land clearing, excavation, and site grading follow the design phase.

#3: Land Clearing Phase

Time to Completion: One to 36 months

Land survey teams map and set control lines. These lines run end-to-end on the road or highway. They will then create reference points to guide the construction crews in the development of the road. Any pre-existing infrastructure must also be demolished and removed to ensure access. Once the land clearing is completed, a stable foundation is established through site grading, providing the roadways’ permanency. Dust control, soil nailing, and other substantial work requiring a civil engineering contractor in Phoenix is conducted during this stage as well.

#4: The Paving Phase

Time to Completion: One to six months

Asphalt offers substantial benefits such as reduced noise pollution, improved motorist comfort, and increased longevity. It is also a cost-efficient alternative to other pavement types. That is why most states, like Arizona, choose asphalt for new infrastructure. Asphalt is typically five percent bitumen, a petroleum product, and 95% aggregates such as sand and crushed rock. This mixture is heated between 200˚F and 330˚F, depending on asphalt type, then laid and compacted along the roadway. It is then given enough time to cure.

#5: Open to Arizona Motorists

Time to Completion: Zero to six months

Good news, motorists. The Arizona Department of Transportation will soon open the South Mountain Freeway to you. Before that happens, however, the project must pass several rigorous inspections. Ride quality and appropriate drainage are included in these inspections. Additional site grading may be required based on the results. Finally, message boards and landscaping is installed (where applicable), and permanent pavement markings are applied.

Buesing Corp is a leader in the construction industry as a civil engineering contractor in Phoenix. In business since 1965, we perform most of our work on projects as a specialty contractor on select civil-related projects such as the South Mountain, Loop 202 Freeway project in the west valley. On this project, we performed permanent shoring/earth retention in seven phases related to the Loop 202 and I-10 traffic interchange in west Phoenix, which is part of the new Loop 202/South Mountain Freeway Project.

Loop 202/South Mountain Freeway Project Details and Video

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