Like a first-class jigsaw puzzle, key pieces of the Fern Valley Interchange project are falling into place around Phoenix as the two-year, $72 million interchange project rounds the corner for the last six months of construction work.
The project is scheduled for completion in September.
The Luman Road intersection was paved with concrete over a weekend in early February, which allowed the diverging diamond interchange to partially open the next week.
“The opening of the interchange is a milestone, even in its partial configuration,” said ODOT Project Manager Tim Fletcher.
In an effort to get the interchange open in mid-February, prime contractor Hamilton Construction striped the lanes with temporary paint. Once the weather improves, permanent durable striping will be applied with black striping next to the white for contrast.
“There will be some adjustment to the current striping locations to help drivers understand where they need to stop at the intersection,” said Fletcher.
Signing in the interchange area has already been fine-tuned, especially around the temporary northbound I-5 off-ramp, since the partial opening.
Hamilton Construction has since completed demolition of the old two-lane interstate bridge and focused on new I-5 ramps on the south end of the interchange.
Other portions of the project will be completed this spring, including the second half of the new Bear Creek Bridge.
“We’ve known since the first day that this would be a challenging project,” said ODOT Public Information Officer Gary Leaming. “This project involves building new roads, new ramps and new bridges. We’re also improving Oregon 99.”
ODOT expects the southbound on-ramp to open in May. To tie in the new and the existing temporary ramp, the southbound ramp onto I-5 will be temporarily closed from Exit 24 for several days. Meanwhile, the west side of Oregon 99 will be in full construction, wrapping up with new asphalt paving.
Diverging Diamond Design
The Fern Valley Interchange features Oregon’s first Diverging Diamond design, which reduced ODOT’s right of way needs for construction.
“The Diverging Diamond design was developed specifically with Phoenix in mind,” said Leaming. “The objective was to reduce the project footprint. That reduces the project’s impact on surrounding businesses and reduces right of way costs. The design also provides better traffic capacity and safety for motorists.
“To enter I-5 or cross over it, drivers move to the opposite side of the bridge, which reduces the number of signal phases a driver needs to clear.”
‘Show Me State’ Inspiration
The Missouri Department of Transportation was the first public agency in the United States to construct an interchange with this diamond design. Several additional DOTs across the nation have since adopted the design and successfully built new diverging diamond interchanges.
The ODOT project team traveled to Missouri in 2010 to meet with project manager Don Saiko and see the new design first hand. Located on Interstate 44 at the intersection with Missouri Highway 13 in Springfield, the new design moves traffic efficiently and safely through a previously-congested intersection in a major commercial area.
According to Saiko, the new design is important to freight haulers. Time spent sitting in a bottleneck is money lost.
According to Leaming, the trip to Missouri paid dividends for ODOT, capturing lessons learned from Missouri’s effort.
ODOT produced a 3-D traffic simulation video to illustrate how the new interchange design would work.
“It really helped people see how to navigate a diverging diamond interchange,” said Leaming. “The 3-D traffic simulation video is still available online at the project website.”
Problem, Process, Solution
The Fern Valley interchange connects I-5 and Phoenix at Exit 24. The interchange experiences traffic congestion through the day, but is much worse during the morning and evening commutes. Existing and proposed development along the east side of I-5, as well as development growth within the Rogue Valley, are reducing the interchange’s capacity and causing safety concerns.
The project’s design phase began in 2004. The Fern Valley Through design alternative was eliminated in 2009 because it would have an adverse impact on nearby farm land. The Project Development Team later unanimously supported the North Phoenix Through build alternative as part of the federally required environmental assessment.
A $25 million investment from the 2009 Oregon Jobs and Transportation Act — a funding package based in part on increases in truck weight-mile flat fees, registration fees, road use assessment fees, and heavy vehicle trip permit fees — was the last piece of the Fern Valley Interchange project’s funding puzzle.
Unlike previous Oregon transportation bills, the JTA dedicated most of the state’s share of revenue to specific projects. The bill listed 37 projects previously approved by the Oregon Transportation Commission that must be financed by bonds.
That same year, the Phoenix Planning Commission and Phoenix City Council approved an Interchange Area Management Plan for I-5 Exit 24. The IAMP is a requirement of the Oregon Transportation Commission, which sets policy for ODOT.
In 2012, the ODOT project team collaborated with a consortium of private contractors to develop construction methods best suited for the challenges ahead of this project, such as the close proximity of the new bridge ramps to the existing ramps.
Aesthetic features inspired by the natural colors surrounding Phoenix, the hills and grasses, are incorporated in the Fern Valley Interchange project. The use of concrete form liners and different stains and paints presented opportunities to design a bridge with a local look instead of the drab concrete structures commonly built when I-5 was first constructed.
The project team filtered through several designs with the help of Medford landscape architect John Galbraith, before selecting aesthetics for the Fern Valley Road bridges that span I-5 and Bear Creek at Exit 24.
Work Zone Safety
People benefit from many safety features in the Fern Valley Interchange project’s work zone, including TripCheck traffic cameras, the Rogue Valley’s Incident Response vehicle, transverse rumble strips and a reduced speed limit to 50 mph.
The Oregon State Police patrols the work zone. Traffic fines double in work zones, even when there are no workers present. TripCheck cameras were installed to help keep an eye on traffic in the work zone.
“Adding TripCheck cameras to project provides drivers with the timely information they need to avoid congestion during construction,” said Leaming.
ODOT maintains a temporary construction office within The Shoppes at Exit 24 to serve as a base of operations for the project inspectors. The public is welcome to stop by the office for more information.
How Do You Drive a Diverging Diamond Interchange?
The Diverging Diamond Interchange is a different driving experience. The DDI moves traffic more safely and efficiently. Do your homework now. Learn how to drive the DDI.
Project Page: http://goo.gl/9qIVIU
Watch the project video, which shows you how to drive the new Fern Valley interchange at I-5 Exit 24. https://m.youtube.com/watch?v=b01H54zLV0s
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