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ADOT I-17 Improvement Project

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Frequently Asked Questions

General

The I-17 Improvement Project extends along a 23-mile section of Interstate 17 between Anthem Way and Sunset Point.

The I-17 corridor is a vital tourism and commerce corridor, connecting the metro Phoenix area to northern Arizona. ADOT has identified I-17 as a Key Commerce Corridor, which prioritizes improvements to the transportation infrastructure while supporting the greatest potential commercial and economic benefits. Key Commerce Corridors connect the major economic centers of Arizona with local, regional, and international markets. These inter-regional routes are the most essential for future, quality economic development in Arizona and support high-quality job growth. Efficient movement of people, supplies, and goods support tourism, along with the growth and expansion of base industries and the state’s overall economy.

This project is divided into two segments and the improvements for each are detailed below.

Anthem Way to Black Canyon City (Widening) Improvements:

  • An additional northbound and southbound lane.
  • Northbound widening on the median side.
  • Southbound widening on the median side in some sections and widening on the outside in other sections.

Black Canyon City to Sunset Point (Flex Lanes) Improvements:

  • Construct two flexible travel (flex) lanes alongside the existing southbound lanes of I-17. The flex lanes will be separated from the southbound roadway by a concrete barrier.
  • Flex lanes will be open to northbound or southbound traffic, depending on the peak traffic direction and the greatest need.

All highways in Arizona are required to meet federal safety standards. The 23 miles of improvements, including the addition of one lane in each direction between Anthem Way and Black Canyon City and the flex lane improvements from Black Canyon City to Sunset Point, are expected to improve capacity and reduce congestion. The flex lanes will add capacity in the peak travel direction, as well as provide flexibility for managing traffic during maintenance activities, emergency situations and crash-related restrictions. Adding capacity improves safety by increasing the space between vehicles, providing drivers more time to make decisions. It's also up to all drivers to make good decisions behind the wheel, so crashes don't occur and cause unnecessary back-ups that affect everyone.

In the event of a crash that blocks lanes, both the flex lanes and the additional general purpose lanes will add capacity for drivers to travel safely through the affected areas.

Frontage road improvements are not included in this project.

Due to the very mountainous terrain, adding an additional lane on the northbound side of the highway would be very difficult – and costly. In addition, adding lanes to this segment would require severe restrictions during construction, with no viable detours, causing potential delays of two or more hours for drivers traveling through the work zone.

This project was procured as a design-build-operate-maintain (DBOM), Public-Private Partnership (P3). This means that the developer team includes design, construction, operation and maintenance components to meet this contract. Since this is a DBOM project, design and construction may occur concurrently during some phases. In addition, the developer will operate the flex lane system for six months and maintain the flex lanes segment for three years following construction completion.

Traffic on weekends and holidays causes increased congestion, often creating long delays for drivers. This project will increase vehicle capacity and traffic flow, with the potential to alleviate certain traffic concerns and help create a safer corridor.

Interstate 17 is a heavily traveled corridor. The section that is being improved sees more than 1 million travelers annually. Traffic on weekends and holidays causes increased congestion, often creating long delays for drivers. This project will increase capacity in both the northbound and southbound directions, helping to alleviate traffic congestion. In addition, the creation of the flex lanes will allow peak traffic to flow faster and more efficiently. The increased capacity and improved traffic flow will help to improve safety for everyone on the road.

  • Flex lanes are a system that allows ADOT to vary the number of northbound or southbound lanes during peak travel times, or if there is a crash or another emergency situation that causes traffic delays.
  • Two additional lanes will be constructed adjacent to the existing southbound lanes. They will be open to northbound or southbound traffic, depending on peak travel times or the greatest need.
  • Overhead signage and electronic gates will alert motorists to which direction is open for traffic. The technology will be monitored and controlled by ADOT’s Traffic Operations Center.

No, these will be the first flex lanes on the state highway system.

No, they will not.

ADOT anticipates work will begin in 2022 and last approximately three years.

The total project cost is $445,940,000, which includes the construction cost by the Kiewit-Fann Joint Venture developer team, along with ADOT’s cost to administer the project.

In February 2021, Governor Doug Ducey announced $40 million in funding for the I-17 Improvement Project from higher-than-anticipated revenue amid Arizona’s strong economic recovery and federal COVID-relief funds. Additional project funding sources include:

  • $175.9 million from federal aid with matching state highway funds
  • $130 million of state highway funds appropriated by the state legislature in 2019
  • $90 million from an Infrastructure for Rebuilding America grant
  • $50 million programmed by the Maricopa Association of Governments for the Maricopa County portion of the project

Sound walls, the most common type of noise-reducing barrier, are designed to limit traffic noise that travels into nearby areas. ADOT and the Developer are currently studying where sound walls will need to be constructed throughout the project area.

Looking to stay involved in the project? Sign up for updates through our newsletter, submit questions or comments through the website, or keep up with construction by watching our progress live. In addition, a virtual public meeting will be held prior to the start of construction to provide an overview of the project and an opportunity for the public to ask questions. Specific details will be shared as we get closer to construction.

Stay up to date on this project by visiting the project website (Improvingi17.com), signing up for our newsletter and emails, or following us on social media.

Kiewit-Fann Joint Venture has been selected as the developer team for the I-17 Improvement Project. Key members of the developer team 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.

Construction

We want you and our crews to get home safely, which is why the speed limit will be reduced to 55 mph during construction.

ADOT anticipates construction will begin in 2022 and take approximately three years to complete. This timeline allows construction crews to minimize impacts on the traveling public while work is underway. The construction work will be done primarily during weekdays, with lane closures scheduled at night. There will be no scheduled weekend lane closures, allowing for access to I-17 during peak travel days and times.

The project website (Improvingi17.com) is a great resource for up-to-date information on this major project! Information is posted regularly under the construction tab, or you can sign up for construction updates/traffic alerts, visit az511.gov or call 511 (except while driving).

Construction adjacent to the existing I-17 travel lanes will occur primarily during weekdays. Work that requires lane closures will be scheduled during weeknights. There will be no scheduled lane closures on weekends, so I-17 traffic is not impacted by construction during peak travel days and times.

Throughout the 23-mile project, crews will replace two bridges and widen 10 others. Design and construction of the bridges will happen concurrently. For example, once a bridge design has been approved for construction, the design team will begin finalizing design of the next bridge. Once all designs are complete, drivers should anticipate seeing multiple bridges under construction at one time.

Construction is not anticipated to impact weekend or holiday travel. The construction work will be done primarily during the weekdays, with lane closures scheduled on weeknights, Sunday through Thursday on the northbound side and Monday through Friday on the southbound side. There will be no scheduled weekend lane closures, allowing for access to this corridor during peak travel days and times. Unscheduled restrictions or closures might be necessary in case of an emergency or other unplanned incident.

Weekdays/Weekends

  • There will be no scheduled weekday or weekend lane closures, barring any unforeseen circumstances.

Weeknights

  • The project will require lane closures, but the majority of them will occur on weeknights, Sunday through Thursday in the northbound direction and Monday through Thursday in the southbound direction.

Yes, as a part of the construction process, controlled rock blasting will occur within the project area.

Yes, intersections and freeway ramps will be closed during specific construction activities.

No direct business access points will be impacted by construction, so there are no planned closures to business access as a result of construction. However, at times it might take longer to get to businesses along I-17 because of construction work.

ADOT will maintain an open travel lane on Interstate 17 for commercial truck drivers and other motorists when full, overnight highway closures are in place. Crews will use signage and traffic control devices to guide motorists through median crossover lanes and into a single travel lane on the opposing side of I-17 to bypass the closure, and to re-enter I-17 in their original direction of travel. Depending on traffic volume and other driving conditions, delays are likely and could be lengthy. All travelers should plan ahead for reduced speed limits and slow or stopped traffic, and allow extra time.

Operations

The speed limit will be 65 mph.

Overhead message signs will alert drivers which direction is in use, and an electronic gate system will control access to the flex lanes. ADOT’s Traffic Operation Center will monitor and control the electronic gate system.

Should an incident occur within the flex lanes, traffic can be diverted back to the southbound lanes. There are four locations where barrier gates must be installed in the barrier between the flex lanes and the existing southbound general purpose lanes. These barrier gates will allow emergency vehicles to open the gates and clear traffic out of the flex lanes and into the southbound general purpose lanes.

Yes, the flex lanes will have a shoulder to pull over, in case of emergencies.

State laws prohibit ADOT from restricting commercial trucks from using the flex lanes. However, signage will recommend slower-moving vehicles remain on the main lanes.

No, however, signage will recommend slower-moving vehicles to stay on the main lanes of I-17.

Yes, the flex lanes will include two lanes. Drivers can use the left lane to pass, if needed.

In order to extend the project all the way to Flagstaff, an extensive environmental study would need to be completed. This would require a significant amount of additional funding for the study, the design process, and the construction. Currently, no additional funding is available.

• Widening the highway in both directions of the 23-mile section of I-17 was studied, however several factors contributed to the decision to deem it an unfeasible alternative during the environmental study.

Widening between Black Canyon City and Sunset Point:

  • Much of the northbound stretch of I-17 from Black Canyon City to Sunset Point is in an extremely mountainous area. This difficult terrain would require extensive modifications to the existing roadway to meet current design standards, beyond simply just widening the lanes and adding additional shoulder area.
  • Causing minimal disruptions to this highly traveled corridor was another major factor when considering alternatives. Widening the existing roadway would cause an extreme disruption to traffic over a prolonged period of time with no viable alternative route available.
  • To widen the lanes, complete closures of at least one and possibly both lanes in both directions would be needed to complete earthwork operations, including blasting and mitigation of rock fall hazards.
  • These factors would cause extreme traffic interruptions and the cost would be prohibitive.

Widening between Sunset Point and Flagstaff:

  • The environmental and preliminary design study was conducted between Anthem and Sunset Point. Several alternatives were considered and evaluated, and the widening and flex lanes alternative was selected as the preferred improvements.
  • Additional environmental studies would need to be conducted in compliance with the National Environmental Policy Act (NEPA). Those studies would identify the purpose and need for improvements; identify environmental effects of the project; and identify ways to avoid, minimize or mitigate impacts to the natural and human environment. If a preferred alternative was selected, additional funding would be necessary for design and construction.

The flex lanes will be equipped with an electronic gate system and net barriers that slow and stop vehicles from entering the roadway in the wrong direction. In addition, there will be overhead signs alerting drivers to which direction is in use. The entire system will be monitored and controlled by ADOT’s Traffic Operations Center.


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