FAQ - Loop 202 (South Mountain Freeway)

Loop 202 South Mountain Freeway

Project Information
Stay In the Loop
Noise Testing
Shared-Use Path

Frequently Asked Questions

The FAQ below provides general information related to the Loop 202 (South Mountain Freeway). For more detailed information, please refer to the Record of Decision or the Environmental Impact Statement documents. The Record of Decision also includes a more detailed FAQ section in Volume 1, section 9, Public Outreach and Comments Received on the Final EIS and Errata, and Record of Decision, Volume II, beginning on page A371.

Freeway Noise

Why is ADOT continuing to measure noise levels on the South Mountain Freeway?

ADOT is conducting noise measurements in compliance with the Final Environmental Impact Statement (FEIS) for the South Mountain Freeway. Further, ADOT will evaluate the common noise environment within the project area after the freeway is “fully operational.”

What does it mean that the freeway is “fully operational?”

“Fully operational” means that the monitoring systems and overall conditions on the freeway are conducive to continuous, uninterrupted, and free-flow traffic operations, and that the traffic volumes are aligned with the levels predicted by the Maricopa Association of Governments (MAG) travel demand model for the year 2020. 

When is ADOT going to conduct additional noise measurements?

Because of the COVID-19 pandemic, average daily traffic volumes throughout Maricopa county are lower than usual. Taking noise measurements during this pandemic is not representative of typical traffic noise levels. ADOT is planning to resume field noise testing in late summer/early fall 2020 and in late February/early March 2021. Beyond that, ADOT will continue testing noise levels throughout the 22-mile corridor regularly in select locations. Schedules are subject to change because of the pandemic and other unforeseen situations. Updated information will be posted on the project website at southmountainfreeway.com when it is confirmed.

Where will ADOT conduct noise measurements?

Measurements will be taken at representative locations along the South Mountain Freeway; that is, residential neighborhoods, parks, schools and similar locations. Measurements are typically restricted to exterior areas of frequent human use. Interior measurements are taken only when there are no outside activities, such as at churches, hospitals and libraries. Measurements are typically taken in one of three exterior locations: (1) at or near the highway right-of-way line; (2) at or near buildings in residential areas; and (3) at an area between the right-of-way line and the building where frequent human activity occurs, such as a patio or the yard of a home. ADOT will cover all noise-sensitive areas throughout the 22-mile corridor, within the project limits, at areas within approximately 1,000 feet from the freeway. A map with the location, date and time of the field noise measurements will be posted on the project website at southmountainfreeway.com when it is confirmed.

How does ADOT determine the time of day to conduct noise measurements?

ADOT utilizes data collected from the permanent automatic traffic recorders, an integral part of ADOT’s traffic data management system. That data will provide hourly/daily traffic patterns which, in turn, will provide the periods that the freeway operates at or close to “level of service c” – the highest level of traffic noise based on traffic volume and travel speeds. ADOT will continue to evaluate data and determine 2.5-hour windows of time - in the morning and afternoon - with similar traffic volumes when testing would occur. As previously noted, this will occur when average daily traffic counts return to more typical conditions. 

When is the traffic loudest?

While there are many factors that may have a potential to influence traffic noise, traffic volume is the predominant factor. With that said, traffic is at its loudest when the traffic operates at Level of Service C. This is the condition of a stable flow of vehicles, at or near free flow in a lane, but lane changing and maneuverability may be challenging. During Level of Service C at 70 mph, there are approximately 1,500 vehicles per hour and per lane. When traffic volumes increase beyond Level of Service C, vehicle speeds decrease and lower the noise levels.

The correlation between traffic volumes and noise levels is a helpful tool for ADOT to determine the future noise levels based on current conditions. Generally, doubling the traffic may increase noise levels by 3 decibels (dBA), and an increase of 20- 25 percent in traffic volume may increase noise levels by 1 dBA.

Can I request that my residence is included in the noise measurement schedule?

At this time, ADOT is not scheduling noise measurements at specific homes or locations upon request. In alignment with the Final EIS, ADOT will conduct noise measurements in noise-sensitive areas along the entire corridor and share the results of decibel readings in correlation with each location.

How long will the noise measurement process last?

Given the length of the corridor, number of residential areas and limited number of hours in the morning and afternoon for measurements, ADOT anticipates that each round of noise measurements will take approximately three to four weeks to complete. ADOT will make every effort to complete the measurements as quickly as possible, but also must account for unforeseen events that might require repeating of noise measurements.

Where and when can I review the results of noise measurements?

Allow one to two weeks following testing for the team to analyze data and compile the technical memorandum. Once completed, ADOT will post information on the project website at SouthMountainFreeway.com. Schedules are subject to change because of the pandemic and other unforeseen situations.

What action will ADOT take after evaluating the results of noise measurements?

ADOT will share the results of field noise measurements with its project partners, including members of the public and key stakeholders. ADOT will make every reasonable effort to address concerns and be innovative and flexible within the federal and state regulatory framework for noise mitigation. Keep in mind that if the noise levels (expressed in LeqA1h) are at or above 64 dBA, it does not guarantee a noise wall will be constructed, as other factors must also be considered. ADOT will explore other possible innovative methods to reduce noise levels. Learn more about ADOT’s Noise Mitigation Policy at azdotgov/business/environmental-planning/noise. Chapter 6 of this policy provides information about the three reasonableness factors, or “tests,” that must collectively be achieved for a noise abatement measure to be deemed reasonable.

Where can I learn more about highway noise mitigation?

Highway traffic as a noise source creates complexities when it comes to analysis and mitigation, and ADOT understands that you may have additional questions. There are many factors, all of which are relevant, such as traffic volumes and speed, traffic mix, pavement and atmospheric conditions that can impact noise levels. That is why the Federal Highway Administration has provided regulation and guidance on how to analyze and mitigate highway-related noise. The following resources provide information you might find useful:

FHWA - Highway Traffic and Construction Noise - Regulation and Guidance:

https://www.fhwa.dot.gov/Environment/noise/regulations_ and_guidance/

FHWA - Noise Policy FAQs - Frequently Asked Questions:

https://www.fhwa.dot.gov/environment/noise/regulations_ and_guidance/faq_nois.cfm

ADOT – Environmental Planning – Noise:


US DOT - National Transportation Library:


Construction and Schedule

The SMF is open, but I still see construction. When will all construction be complete?

Although the freeway is open to traffic, various construction activities remain ongoing. These activities may include street improvements that require minor traffic shifts;  landscaping; construction of the shared-use path; construction of the 32nd Street traffic interchange ramps; construction of the 59th Avenue frontage road in the I-10 Segment; rubberized asphalt paving; final striping and installation of reflectors on the east- and westbound lanes in the Pecos Segment; and other activities on I-10. The project is scheduled for completion in fall 2020.

Where can I find a construction schedule?

A construction schedule is available on the Construction Info page. ADOT encourages community members to visit the Follow Us page and sign up for project and construction alerts and updates, which are sent weekly via email and/or text message.

How can I be notified of project updates?

ADOT will keep the public up-to-date throughout construction of the freeway. Information is available on the project website; be sure to sign up for weekly email and text message alerts (sign up through the Follow Us page).

When will the shared-use path be complete?

The shared-use path is scheduled for completion this fall.

What is the high-level construction schedule for the 32nd Street interchange?

The below activities are subject to change and are weather dependent:

  • April/May 2020
    • ​Ramp barrier and catch basins
    • Grading and paving
    • 32nd Street southbound: road construction through end of April/early May
    • 32nd Street northbound: road construction in early May to June
  • June/July 2020
    • ​Cast in place walls
    • Visual wall footings and masonry for ramps
    • Grading and paving
    • Drainage and basin culverts

How will construction noise be reduced?

There are two primary sources of noise during major construction activities: equipment engine noise and back-up alarms. While the construction team understands these alarms can be disruptive to nearby residents, they are a vital safety feature proven to reduce the number of construction fatalities. OSHA requires the alarms to be used and to be audible above the surrounding construction noise.

How is dust controlled?

Dust control is always a priority for the construction team. Keeping the soil moist during ground-disturbing activities is the most effective means for preventing dust. Water spraying and soil stabilization materials are used in all construction areas before, during and after construction activity.

Traffic Restrictions During Construction

How do I get information about construction activities and alternate routes?

ADOT sends weekly emails and text message alerts regarding construction activities, restrictions and closures. ADOT encourages individuals who live or travel near the future freeway to sign up for project alerts on the Follow Us page.

When will I be able to drive on 59th Avenue?

The project team anticipates 59th Avenue will be open to traffic in summer 2020. On 59th Avenue – like many other major roadways adjacent to and part of the freeway project – intermittent street and lane closures are required for the safety of the community. When closures are in place, adequate detours with clear signage are provided.

Freeway Maintenance

Who will maintain the freeway once the design-builder has completed construction?

The SMF project is part of a Design-Build-Maintain Agreement, or DBMA. The DBMA is between C202Pand ADOT. C202P, who is responsible for the design-build work, will also be responsible for maintaining the freeway for 30 years.

How will maintenance be handled?

C202P will handle all maintenance, including pothole repairs, signage, rehabilitation and striping. C202P must adhere to strict performance standards set forth by ADOT. If the highway is not maintained to these specified performance measures, C202P will incur financial penalties.


I have seen a red right turn arrow in the Pecos Segment. What does that arrow mean?

A right red arrow means No Right on Red, and should be treated as a red traffic light, per the Arizona Driver’s License Manual. This means traffic cannot turn right on red and must remain stopped until the arrow turns green.

How was the freeway funded and built?

The freeway was funded by state, federal and local dollars. It is not tolled. The final design, construction and 30-year maintenance of the freeway occurred through a public-private partnership (P3) agreement with C202P. This P3 not only expedited construction, but also reduced the overall cost. This project would have cost an estimated $100 million more than it did if ADOT had not utilized a P3 and the design-build project delivery method. Those saving are reabsorbed by the Maricopa Association of Governments’ Regional Transportation Plan to be put toward other infrastructure projects in the region.

What is the public private partnership and how does it benefit taxpayers?

A P3 refers to the contractual agreement between a public agency and a private sector entity to have greater participation in the delivery of a transportation project. By securing a P3, the entire SMF project can be constructed as one project rather than nine, as originally scheduled, which accelerated project delivery by at least three years.

For additional information on the P3 process please visit the P3 Initiatives page.

Who is Connect 202 Partners?

C202P is the developer responsible for the design, building and maintenance of the SMF for 30 years after completion of construction. The team consists of Fluor Enterprises Inc., Granite Construction Co. and Ames Construction Inc., with WSP Inc. as the lead designer.

Does the state retain ownership of the freeway?

Yes. The state retains ownership of the SMF, and C202P is granted a non-exclusive license (not ownership) for 30 years to access and use the freeway and its structures to carry out operations and maintenance. C202P must return to the state a freeway in excellent condition at the end of the maintenance period in 2050. Although C202P must maintain the freeway, ADOT can make improvements, if warranted, at its own cost. Like other state freeway projects, improvements would need to be identified in the Five-Year Transportation Facilities Construction Program and approved by the State Transportation Board.

What has changed about the project since the environmental process and why? 

Since the P3 method encourages innovation and optimization of efficiencies, the current freeway design incorporates some changes from the early design concepts that minimize the right of way impacts while increasing safety and reducing traffic restrictions during construction. Innovation and efficiency examples throughout the freeway corridor include:

Half diverging diamond interchanges at Desert Foothills Parkway and 17th Avenue

Modifying interchanges to improve traffic operations and minimize right of way requirements

Double roundabout configuration at Estrella Drive

Shared-use path along the Pecos Segment

Pedestrian bridge in the Salt River Segment


Where will traffic interchanges be located?

Fifteen traffic interchanges will be located at the following major street crossings:

  • Van Buren Street
  • Buckeye Road
  • Lower Buckeye Road
  • Broadway Road
  • Southern Avenue
  • Baseline Road
  • Dobbins Road
  • Elliot Road
  • Estrella Drive
  • Vee Quiva Way
  • 17th Avenue
  • Desert Foothills Parkway
  • 24th Street
  • 32nd Street
  • 40th Street

How were traffic interchange locations determined? 

Interchange locations were determined during the environmental phase of the project, based on traffic modeling and regional mobility needs. During this process, ADOT coordinated with the city of Phoenix and a Citizens Advisory Team to identify interchange locations. Initially, interchanges were not planned for 32nd Street and Vee Quiva Way. The interchanges were added to the project after construction began in 2016 at the request of area residents, businesses and other key stakeholders and following a re-evaluation of the environmental study.

What is a shared-use path and where will it be located? 

A shared-use path is a physically separated path adjacent to a highway. It accommodates pedestrians, bicyclists and other forms of non-vehicular traffic. The 20-foot wide shared-use path is being constructed between 40th Street and 17th Avenue directly south of the freeway in the Pecos Segment. While C202P is responsible for the design and construction of the shared-use path, the city of Phoenix will be responsible for maintaining the path. Additionally, the shared-use path will provide connectivity complementing the city of Phoenix Comprehensive Bicycle Master Plan.

What is a half diverging diamond interchange?

A Diverging Diamond Interchange (DDI) is based on a standard diamond interchange common in Arizona, but with one major difference —traffic shifts briefly on the left side of the road between highway ramps, allowing left turns without crossing oncoming traffic. The freeway will feature two half-DDIs in the Pecos Segment, as there are no connection points to the south.

Features of a DDI:

  • Innovative, proven solution for increased safety and mobility
  • Able to move increased traffic more quickly and safely than traditional intersections
  • Minimizes right of way footprint over some other types of interchanges
  • Watch a video about driving on the half DDI here

What is a double roundabout interchange? 

A double roundabout interchange resembles the shape of a dog bone from an aerial view. This type of interchange will be constructed at Estrella Drive.

Features of a double roundabout interchange:

  • Reduces conflicts between vehicles
  • Minimizes right of way impacts
  • Improves efficiency
  • Provides a safer design by eliminating the potential for perpendicular collisions

Why isn't there a noise wall near my community?

Noise walls were built in locations that warranted noise mitigation in compliance with state and federal regulations based on noise modeling completed prior to construction.  ADOT will continue to measure noise levels along the entire freeway corridor to evaluate impacts and ensure that noise levels remain at or below what is permitted by state and federal regulations. ADOT’s policy is to reduce the impact of freeway noise on adjacent homes, schools and churches by building sound walls or berms. Based on the noise modeling included in the Environmental Impact Statement, building sound walls ranging in heights from 16 to 20 feet adjacent to the residential communities would minimize the noise impacts of the freeway traffic and meet ADOT’s threshold of 64 decibels which is lower than the federal regulations (67 decibels). As a comparison, conversational speech is typically measured at 60 decibels.

Is ADOT going to address the lights shining in my backyard or home? 

Yes. ADOT continues to evaluate locations where light could be redirected while maintaining the safety of the motoring public. Careful consideration and planning go into adjusting lighting on a mainline urban freeway.   

Will the freeway include rubberized asphalt?

Rubberized asphalt has been used on the SMF to provide a smooth driving surface. It has the added benefit of reducing noise levels by up to four decibels. This material—used for more than 20 years to resurface highways and city streets in Arizona—consists of regular asphalt pavement mixed with recycled rubber tires. In addition to the benefits it provides on the roadway, rubberized asphalt also reduces the number of used tires in landfills.  Final rubberized asphalt paving will occur in the spring of 2020.

Why aren't the bridges on the new freeway paved with rubberized asphalt?

ADOT no longer paves its highway bridges with rubberized asphalt. This is because the rubberized asphalt must be removed and replaced each time a bridge needs to be inspected or if a repair must be made. By not paving bridges with rubberized asphalt, ADOT reduces costs, as well as the need to close or restrict freeways for asphalt removal or replacement. And because rubberized asphalt is a temperature-sensitive product, bridges could be repaved only during optimal conditions that occur twice a year (spring and fall).

Is the freeway wide enough? Will widening be needed in a few years?

The South Mountain Freeway will be constructed as an eight-lane freeway (three general purpose lanes and one HOV lane in each direction). There are no current plans to widen the freeway in the future.

Is there access to the Gila River Indian Community from the traffic interchanges along the Pecos and Center segments?

The 40th Street, Estrella Drive and Vee Quiva Way interchanges provide the Gila River Indian Community direct access to and from the freeway. The Gila River Indian Community is responsible for connecting to the traffic interchanges, in coordination with appropriate jurisdictions.

Planning and Environmental Study

How was it decided to build this freeway?

The SMF has been a critical part of the MAG Regional Freeway Program since it was first included in funding approved by Maricopa County voters in 1985. The SMF was also part of the Regional Transportation Plan funding passed by Maricopa County voters in 2004 through Proposition 400. The SMF is a key component of the region’s adopted multimodal transportation plan and the Regional Freeway and Highway System and is the last piece to complete the Loop 202. The Federal Highway Administration issued a Record of Decision (the final decision-making document for the project) selecting a build alternative on March 5, 2015.

How was the route for the freeway decided?

The route for the freeway was determined through a multidisciplinary process to identify a range of reasonable alternatives that were studied in detail in the Environmental Impact Statement. The study process involved identifying, comparatively screening, and eliminating alternatives based on:

  • input from the public
  • a comparison of alignment alternatives
  • surrounding communities, resources, and other factors
  • the historical context of the freeway
  • projected regional traffic conditions with and without a freeway

The final decision on the route for the freeway was determined by ADOT, the FHWA and MAG, the transportation authority and planning agency for the region. As a corridor that is part of a comprehensive regional plan developed by MAG, ADOT serves as the agency responsible for implementation of the plan, with FHWA providing the federal oversight required to access federal funds. FHWA is the lead federal agency responsible for implementing the requirements of the National Environmental Policy Act, the governing federal law, and was responsible for the ultimate decision in selecting a route for the freeway.

How was public input from the environmental study used?

Public input was a vital component during the environmental study phase and was solicited from project inception through key milestones in the Draft and Final Environmental Impact Statement (EIS) processes. The interests and needs of the public, along with all other social, economic and environmental issues and impacts, were fully analyzed during the study phase of the project. More information about the entire public involvement process up to publication of the Final EIS is available in Chapter 6, Comments and Coordination, of the Final EIS.

Why not consider light rail or other transit instead of a freeway?

The study did consider a variety of transportation alternatives, modes, and strategies that would fit into the Regional Transportation Plan, including transit. The freeway option was determined to best meet the purpose and need for the project, following an extensive screening process which included evaluation of additional benefits such as system linkage, regional mobility, and consistency with regional and local long-range plans.

Why isn't the freeway on Gila River Indian Community land?

While efforts to study alternatives on Community land were attempted, the Community has long held a position of not allowing the freeway to be located on its land. For example, a coordinated referendum of Community members to favor or oppose construction of the freeway on Community land or to support a no-build option occurred in February 2012, and Community members voted in favor of the no‑build option. Therefore, the freeway cannot be located on Community land.

What impact does the freeway have on air quality?

Air quality impacts were estimated through sophisticated computer modeling based on predictions of the amount and nature of traffic under worst-case scenarios. The emissions models are based on extensive emissions testing that the U.S. Environmental Protection Agency (EPA) has conducted on thousands of vehicles representative of the ages and models of the vehicle fleet on the roads today.

The carbon monoxide and particulate matter (PM10) analyses demonstrated that the freeway will not contribute to any new localized violations, increase the frequency or severity of any existing violation, or delay timely attainment of the National Ambient Air Quality Standards or any required interim emissions reductions or other milestones.

Since ozone is a regional pollutant, there is no requirement to analyze potential impacts and no possibility of localized violations of ozone to occur at the project level. The Maricopa Association of Governments is responsible for developing plans to reduce emissions of ozone precursors in the Maricopa area. The South Mountain Freeway is included in the Regional Transportation Plan that has been determined by the U.S. Department of Transportation to conform to the State Implementation Plan on February 12, 2014.

The emission modeling developed for the freeway showed that for the mobile source air toxics study area, there would be little difference in total annual emissions of mobile source air toxics emissions (less than a 1 percent difference) in 2025 and 2035. In addition, beginning in 2017, the new EPA Tier 3 vehicle and fuel standards will reduce tailpipe and evaporative emissions and reduce mobile source air toxics.

The Record of Decision discusses the air quality analyses in greater detail.


How many vehicles will use the freeway?

Chapter 3 of the Final Environmental Impact Statement (FEIS) states traffic projections estimate approximately 117,000 to 190,000 vehicles daily would use the South Mountain Freeway in 2035.

Will the new freeway generate new truck traffic?

Factors considered in the environmental study were the amount of truck traffic that would use the freeway and its potential impact on the surrounding community. The MAG regional travel demand model forecasts approximately 10 percent truck traffic on the South Mountain Freeway in 2035. The forecasted truck traffic is based on existing traffic studies and projected socioeconomic data. This percentage is similar to current traffic conditions on I-10 between Loop 101 and I-17 and on US 60.

Does this freeway serve as a truck bypass to relieve congestion from Downtown Phoenix?

The SMF was not constructed to create a "truck bypass" for downtown Phoenix. The freeway is part of a transportation system developed to improve mobility in the region by increasing capacity and providing traffic alternatives—including truck traffic—to other, already congested routes. As with all other freeways in the MAG region, trucks use the SMF for the through transport of freight, for transport to and from distribution centers, and for transport to support local commerce. It is anticipated that “true” through truck traffic (not having to stop in the Phoenix metropolitan area) would continue to use the faster, designated, and posted bypass system of I-8 and State Route 85. Also, like other “loop” freeways in the Phoenix metropolitan area, the SMF would be a commuter corridor, primarily serving automobiles and helping to move local traffic between the eastern and western portions of Maricopa County.

Are trucks carrying hazardous cargo allowed to use the highway?

Arizona highways, like most highways across the United States, are open to all kinds of traffic, so long as the cargo being carried is in accordance with U.S. Department of Transportation regulations for the specific type of cargo. The Arizona Department of Transportation has a few locations in the state with hazardous cargo restrictions, but these restrictions are based on emergency response issues or roadway design limitations specific to that location. For example, the Interstate 10 Deck Park Tunnel has certain hazardous cargo transport restrictions because of the limited ability for emergency responders to address a hazardous materials incident in the tunnel. The South Mountain Freeway will operate under the same rules as other similar facilities in the state; transport of hazardous cargo will be permissible.

How are international trucks monitored?

Ports of entry monitor all commercial traffic entering Arizona for registration, taxes, size and weight restrictions, commercial driver license requirements, insurance requirements and equipment safety requirements, and issue permits as required. ADOT’s Enforcement and Compliance Division further works to ensure the safe and efficient movement of commercial motor vehicles on highways throughout Arizona.

Is the freeway tolled?

No, this freeway is not tolled and is funded by state, federal, and local dollars.