PHOENIX — On arguably one of the most narrow and winding roadways on the state’s highway system, the Arizona Department of Transportation will soon begin a project that will restore the pavement along a three-and-a-half-mile segment of State Route 89A through the Oak Creek Canyon switchbacks.

Beginning on Monday, April 21, crews will start work on the $2 million improvement project that will repave the roadway between Pine Flat Campground and Oak Creek Vista overlook (mileposts 387-390). The project area is located in the Coconino National Forest midway between Sedona and Flagstaff, just north of the popular tourist destinations in Sedona and Oak Creek Canyon.

In order to complete the work in safe and timely manner, a full closure of SR 89A through the switchbacks, which have steep grades with little to no shoulders, will be necessary for up to five weeks following the Memorial Day holiday and prior to the Fourth of July holiday (May 27 – July 2). While the closure isn’t expected to last more than five weeks, ADOT is offering incentives to the contractor to complete the work as quickly as possible, while focusing on safety and quality. During construction, access will be maintained for emergency vehicles.

During the first phase of the project from April 21 through May 22, a single-lane restriction during daytime hours will be required Monday through Thursday throughout the project length as crews begin preparations for a full closure of SR 89A. The roadway will be open, without lane restrictions, during the Memorial Day weekend, May 23-26.

During this time, access will remain open to Pine Flat Campground and Oak Creek Vista overlook, although flaggers will be present to guide traffic through the work zone. Delays are possible. There will be no restrictions during weekends, holidays, or at night prior to the full closure when there will be no public access.

The timeframe for the full closure from May 27 to July 2 was chosen because it’s the most favorable time to apply the new pavement, which is temperature sensitive, and it’s before monsoon season, when rain can delay paving.

In addition to removing and replacing the existing asphalt, crews will also make repairs to the surface of the historic Pumphouse Wash Bridge and perform rockfall mitigation work in this area, which is prone to rockfalls.

The full closure will allow crews sufficient space to safely perform rock scaling work, which involves workers rappelling from a cliff and using hand tools to remove loose rocks that could potentially fall onto the roadway and injure motorists or damage the roadway.

For Sedona and the Oak Creek Canyon area, it is business as usual during this time because the project is located north of these popular destinations.

During the closure, the recommended detour from Sedona to Flagstaff will be to take State Route 179 to Interstate 17. The detour could add up to an extra half an hour of travel time for motorists who are commuting between Sedona and Flagstaff.

“ADOT understands that some residents and businesses will be inconvenienced during construction, but if this project was done under any other traffic control condition, it would extend the project several months longer, not to mention it would overshoot the ideal temperature window for paving,” said Flagstaff District Engineer Audra Merrick. “In addition, the full closure of SR 89A will allow us to maintain access for emergency responders, at all times, which is especially critical during wildfire season.

“Rest assured, ADOT is working with the contractor to complete the project as soon as possible, and has provided the contractor monetary incentives to complete the project ahead of the scheduled five-week closure.”

During the full closure, access will be maintained at either end of the full closure to allow entry to both Pine Flat Campground on the southern end and Oak Creek Vista overlook at the northern end.

Signage and message boards are currently being used in advance of the closure to ensure traffic is properly detoured via SR 179 to I-17.

For more information on the project, please watch our video with information on the SR 89A switchbacks project.

PHOENIX – Three highway projects by the Arizona Department of Transportation, including two major northern Arizona projects, won Engineering Excellence Grand Awards presented by the American Council of Engineering Companies of Arizona earlier this year. Two other projects received Honor Awards.

The winning projects were the Interstate 17/State Route 69 Cordes Junction Traffic Interchange, the US 89T Interim US 89 Detour and a topographical survey on the State Route 89A improvement project through Oak Creek Canyon.

HDR Engineering, Inc., won a Grand Award for the I-17/SR 69 Cordes Junction traffic interchange project. This project was ADOT’s first federally funded highway project to be built under the construction manager-at-risk (CMAR) method in Arizona. The CMAR concept is an innovative contracting method that involves pairing a design team with a construction team to create one, coordinated entity that delivers a freeway project from beginning to end. This method can save time and money by overlapping the design and construction phases.

The US 89T project, built to serve as a detour to the landslide-damaged US 89, received the award for AZTEC Engineering Group’s coordinated effort to produce roadway plans and get environmental clearance in less than two months. This process normally takes one to two years to complete.

ADOT, the Federal Highway Administration, the Navajo Nation, Navajo Division of Transportation and Bureau of Indian Affairs worked together to accelerate the process in order to open the temporary route as soon as possible. US 89T cuts the original detour route via US 160 and SR 98 nearly in half, saving time and mileage.

The SR 89A improvement project, which will include repaving the roadway, replacing guardrail, repairing the bridge deck at Pumphouse Wash and mitigating rock falls in the area, received the award for David Evans and Associates’ innovative use of laser imaging technologies to conduct a topographical survey. The use of laser imaging resulted in fewer lane closures and significant savings in time and cost. Topographical surveys are a part of the design phase of a roadway project.

Honor Awards were received by URS Corporation for the redesign of the Interstate 10/State Route 90 interchange to solve safety and traffic capacity issues, and by Parsons Brinckerhoff for the Avenue 3E widening project from Gila Ridge Road to 24th Street in Yuma to provide better connectivity through the community.

The American Council of Engineering Companies of Arizona Engineering Excellence Awards competition recognizes engineering firms for projects that demonstrate an exceptional degree of innovation, complexity, achievement and value.

American Council of Engineering Companies of Arizona is a member organization under the American Council of Engineering Companies, and is devoted exclusively to the business interests of engineers in private practice.