South Mountain Freeway construction crews have begun erecting 16- to 20-foot sound walls along Pecos Road as work steamrolls ahead toward the target opening date of late 2019.
“When the Loop 202 South Mountain Freeway opens to traffic in late 2019, sound walls lining one or both sides along 11 of its 22 miles will reduce noise near neighborhoods and incorporate designs specific to various segments,” the Arizona Department of Transportation said in a release last week.
The walls began going up between 40th and 48 streets in Ahwatukee as well as the western end of the freeway at 59th Avenue in west Phoenix.
ADOT called the walls “the most common type of noise-reducing barrier used” along Valley freeways, stating they will “limit the intensity of freeway traffic noise that travels into nearby areas.”
“Extensive studies helped determine where sound walls are needed for the South Mountain Freeway,” the department said.
While some walls are expected to be as high as 24 feet, most will be no higher than 20. Ultimately, ADOT will use more than a million concrete blocks to build the barriers.
“Sounds walls can significantly reduce freeway noise by blocking the path that sound waves travel from the traffic toward a residential area,” said Rob Samour, ADOT’s senior deputy state engineer for major projects. “Combined with our use of rubberized asphalt pavement, we’ll be able to limit traffic noise throughout the entire corridor, similar to other Valley freeways.”
Construction involves installing concrete footings for foundations, along with placing reinforced steel within the footings to support masonry blocks that are stacked layer upon layer.
The walls will be painted and aesthetic panels will be added at a later date to make them more visually pleasing, ADOT said.
It said the decorations will reflect the freeway’s “distinctive aesthetic character areas complementing its surroundings, helping tell an area’s story and creating a more appealing environment for drivers.”
One pattern will evoke the Laveen area’s agricultural heritage, while others – including those in Ahwatukee – will feature desert plants and simple shapes based on native cholla and ocotillo cactuses.
In contrast to vertical lines on walls along other Valley freeways, the South Mountain Freeway’s sound and retaining walls will display horizontal lines.
“These were designed in collaboration with the Frank Lloyd Wright Foundation to honor the legendary architect’s connection with the South Mountain foothills, where he worked on the design for a resort that wasn’t built following the 1929 stock market crash,” ADOT said.
Erection of the walls also is another sign that ADOT doesn’t appear worried that a pending appeal before the U.S. Court of Appeals for the Ninth Circuit will halt the work.
The appeal is awaiting a decision by a three-judge panel.