In last month’s issue, part one of this story reviewed the complicated history of the South Mountain Freeway, part of the Loop 202 and Loop 101 system in metropolitan Phoenix. The freeway – designed to offer a direct link between the region's East Valley and West Valley, and provide an alternative to I-10 through downtown Phoenix – was originally approved by Maricopa County voters in 1985, and again in 2004, as part of a comprehensive regional transportation plan. However, the project did not receive final approval from the Federal Highway Administration (FHWA) until March 2015, an indicator of the controversy and opposition which has followed the project from its inception.
Since the project was first proposed, tensions have lingered between three groups: regional transportation planners, who maintained that the freeway was necessary to ensure smooth traffic flow; the residents of the adjacent Ahwatukee community, who feared losing over 100 homes to eminent domain due to the project's alignment; and the residents of the adjoining Gila River Indian Community (GRIC), who opposed any alignment that impacted the South Mountains.
Reports Dustin Krugel, Public Information Officer for the Arizona Department of Transportation (ADOT), “Several potential non-freeway options were identified during the transportation planning process – including light rail, commuter rail, bus routes, van pools, additional streets and improved intersections. These alternatives were evaluated as part of the study through a screening process, but ultimately these alternatives alone or in a combination would not have efficiently addressed the projected traffic demand anticipated in the southwest and southeast areas of metro Phoenix.
“Many alternatives, including the no-build alternative, were examined to avoid the South Mountains. However, none of these alternatives were feasible or prudent. For instance, some alternatives were dismissed because they did not meet transportation demands of the region, required substantial displacement of homeowners and businesses, proved too costly, were limited by the physical constraints of the South Mountains and were restricted by the inability to move forward with alternatives on Gila River Indian Community land.”
After years of funding issues, legal challenges and ongoing efforts to address all the relevant issues, the South Mountain Freeway project is now progressing at a steady pace. Completion is expected in late 2019, Krugel reports, adding that approximately 117,000 to 190,000 vehicles are forecast to use the freeway daily by 2035.
DBM Contract is First to Utilize Arizona’s P3 Statute
For what is the largest project in state history, in February 2016 ADOT awarded a design-build-maintain (DBM) contract to Connect 202 Partners, LLC, a joint venture led by Fluor Corporation. Fluor, Granite Construction, Ames Construction, and infrastructure design firm Parsons Brinckerhoff have responsibility for final design and construction; Fluor and maintenance services contractor DBi Services, LLC will be jointly responsible for ongoing highway maintenance activities and any necessary capital improvements for 30 years.
This project is the first freeway project procured under Arizona’s public-private-partnership (P3) statute and ADOT’s first design-build-maintain project ever. The $1.77 billion project is funded by a combination of Regional Area Road Fund revenues, Highway User Revenue Fund revenues and federal funds dedicated to the Maricopa County region and ADOT.
As Krugel explains, the DMB model accelerates construction schedules, with design, right-of-way acquisition, and construction activities occurring concurrently. “By opting to make the South Mountain Freeway the state’s first highway public-private-partnership project and using the design-build-maintain delivery method, this innovative approach will allow ADOT to construct the project at an accelerated pace and reduce the overall cost of the project, which can be passed onto taxpayers.
“Had the South Mountain Freeway been delivered under traditional project delivery methods, such as a design-bid-build by segment model, the project would have been split into several smaller projects,” he continues. “This would not be as efficient, as work would be split by several contractors and would take additional time to complete. By keeping one development team, the South Mountain Freeway can be accelerated and taxpayers, ADOT and the developer will reap cost savings by not having to tie up resources, personnel and equipment to the project.”
Project Features Arizona’s First Diverging Diamond Interchanges
The 22-mile-long South Mountain Freeway will run east and west along Pecos Road and then north and south between 55th and 63rd avenues, connecting with Interstate 10 on each end. The first phase of construction began in September 2016.
A 6-mile stretch of the freeway, from 40th Street to 17th Avenue, will include a 20-foot-wide shared-use path on its south side. The path, which will also be open to pedestrians, was included because the existing roadway had been a popular cycling route for years.
In early 2017, ADOT announced an updated design for the freeway, including Arizona's first diverging diamond interchanges at Desert Foothills Parkway and 17th Avenue; a reconfiguration near 51st Avenue that moves the freeway interchange to avoid a GRIC well; and a pedestrian bridge to connect subdivisions divided by the freeway.
Krugel comments, “ADOT is always looking at creative and innovative solutions to enhance safety and improve traffic flow, and the diverging diamond interchange is just one of the tools in ADOT’s engineering toolbox to meet traffic demands. Careful consideration is taken in deciding which tool to use for each specific location.
“The diverging diamond interchange is an innovative, proven solution for improving safety and mobility at interchanges for motorists, cyclists and pedestrians. These interchanges can move a high volume of traffic more efficiently and safely than traditional intersections and can often be constructed at a lower cost.
“Recent traffic studies of existing diverging diamond interchanges show a significant reduction of major crashes, an overall reduction in delay times, and an increase in overall capacity. To date, there are more than 60 diverging diamond interchanges in the U.S. and many more are in either in design or development.
“Along with the two South Mountain Freeway interchanges, ADOT is currently planning other diverging diamond interchanges, including at Interstate 17 and Happy Valley Road in Phoenix and I-10 at Houghton Road east of downtown Tucson.”
In addition to 22 new miles of roadway and 4.5 miles of improvements along I-10, the project includes 40 bridges and 13 interchanges, 11 miles of sound walls, 6 miles of shared-use path, and a pedestrian bridge. Even a partial list of estimated quantities to be utilized helps illustrate the scope of the project:
Aesthetic Enhancements Inspired By Architect Frank Lloyd Wright
In addition to its significance as a major response to traffic needs in the Phoenix area, the South Mountain Freeway will feature a noteworthy approach to visual appeal, with colors and design themes that honor an American icon.
As Krugel explains, “It’s not well known, but the early winter encampment of renowned architect Frank Lloyd Wright was near the new freeway location on the slopes of South Mountain[Wright had a camp, called “Ocotillo,” in the late 1920s in the area now known as Ahwatuke]. With this in mind, ADOT and Connect 202 Partners have partnered with the Frank Lloyd Wright Foundation to provide aesthetic features for the freeway bridges, noise walls and landscape. The designs, inspired by some of Wright’s earlier work, will help establish a sense of place for the Freeway and its various sections. The aesthetics will attempt to tell a story by showing differences in land uses, land forms, and history in each area.”
A common feature of Wright’s structure, Krugel points out, was his frequent use of horizontal lines, which were boldly expressed in the wood walls of his Ocotillo camp that echo the flat desert floor and long desert horizons. The horizontal lines have served as an influence on the freeway designs, which feature such lines along all the sound walls and retaining walls – in contrast with the vertical lines of other Valley freeways. Desert earth-tone base paint will be used throughout the 22-mile corridor, along with a reddish accent color resembling an ocotillo flower on the retaining walls, abutments and bridge barriers.
Photos courtesy of the Arizona Department of Transportation
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