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Fern Valley Interchange Project: I-5 motorists brace for 25 days of single-lane traffic

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Construction workers and equipment are in full force at the Interstate 5 exit 24 interchange for Phoenix. With utility work wrapping up, prime contractor Hamilton Construction of Springfield began major road work on the Fern Valley Interchange project, which builds Oregon’s first crossing diamond interchange.

The $72 million Fern Valley Interchange project addresses Phoenix’s I-5 interchange. Traffic congestion is especially severe during the morning and evening commutes. Existing and proposed development along the east side of I-5 in Phoenix has reduced the capacity and created safety issues at the interchange.

The project area includes I-5, Oregon 99 and Fern Valley Road. Hamilton Construction crews and subcontractors are building the new Grove Road and excavating the new North Phoenix Road alignment on the east side of the I-5 interchange. The contractor will then work west toward Oregon 99. The project is designed to also realign North Phoenix Road between Peterbuilt Motors Co. and Home Depot.

Due to the size and complexity of the project, more than two full construction seasons will be needed to complete the job. The project is scheduled for completion in September 2016.

I-5 pipe crossing delays

Before Memorial Day weekend, prime contractor Hamilton Construction will install a four-foot drainage pipe across I-5. The project contract stipulates that this work must be completed in a 25-day work window.

Hamilton Construction will need to narrow I-5 to a single lane in each direction, so that an open trench can be dug to install the drainage pipe. Motorists will encounter significant congestions and delays during this
25-day period.

“Local drivers should plan ahead, leave early and consider taking a different route to get to their destinations on time,” said ODOT Project Information Specialist Gary Leaming. “Like local drivers saw first-hand during the South Medford Interchange project, the best scenario is to leave I-5 for through traffic and have commuters take advantage of alternate routes like Oregon 99.”

ODOT looked into ramming the drainage pipe under I-5 to reduce the impact on motorists. However, many large boulders were found during the study. Used as a road base, the boulders left pipe ramming as an unusable option.

Information sharing

“We had great attendance at our pre-construction open house in February,” Leaming said. “Our goal is to maintain a high level of visibility throughout the length of the project.

ODOT opened a temporary construction office within “The Shoppes at Exit 24” shopping mall. The office serves as a base of operations for the project inspectors, although the public is welcome to stop by the office for more information.

ODOT Public Service Representative Dennis Steers can be reached directly at 541-621-7034 or Steers is pounding the pavement, meeting with property owners and the general public to keep them informed of the work ahead.

“A major project goal is to keep construction impacts to a minimum,” said Steers. “We will use traditional media, social media and other communication resources to reach out to commuters. We want to encourage them to use alternate routes and adjust their travel plans to avoid the busiest traffic periods of the day.

“We will do our best to minimize the construction impacts, but there will be impacts.”

3-D traffic simulation video

“How will drivers negotiate the new interchange design?”

That’s a frequent question from local drivers and Phoenix residents, including stakeholders who have followed the project’s long development process. A 3-D traffic simulation completed in fall 2013 shows how the new crossing diamond interchange will operate.

“There is nothing like people seeing it for themselves,” Leaming said. “The video makes is much easier to explain how the interchange will look when completed.”

The 3-D traffic simulation video is available online at the project website,

“We learned through the project outreach for the South Medford Interchange project that a picture or, in this case, a video, is worth a thousand words,” Leaming said. “Once people see it, people will get it.”

TripCheck cameras will capture Phoenix traffic

New TripCheck cameras installed in the project area will help keep an eye on construction-related traffic.

“Adding TripCheck cameras to the Fern Valley Interchange project will help people navigate the area, especially during the phases when we expect significant congestion,” said Leaming. “Again, our first challenge is the 25-day period before Memorial Day weekend when Hamilton Construction installs a four-foot drainage pipe across I-5.”

The TripCheck cameras are located on the sign bridge spanning northbound I-5, roughly one mile north of the Phoenix interchange. Other cameras are being placed east and west of the I-5 interchange.

“TripCheck cameras were invaluable to the public during the South Medford Interchange project,” Leaming said. “The new cameras in Phoenix will also give motorists the information they need to avoid congestion.”

Crossing diamond design

The project design constructs the new interchange at a location just north of the existing bridge, leaving most roadways west of the interchange relatively untouched. The crossing diamond design has a narrow footprint, which helps avoid touching nearly all the businesses during and after the I-5 interchange project. The crossing diamond design also helps keep traffic congestion to a minimum while increasing safety.

“The interchange’s crossing diamond design provides a higher capacity to move traffic while reducing right of way needs,” said ODOT Project Leader Dick Leever. “Vehicles crossing the interchange move to the opposite side of the road to either enter I-5 or to cross it, reducing the number of signal cycles for traffic to clear.”

The Missouri Department of Transportation was the first public agency in the United States to construct an interchange with the crossing diamond design. Phoenix will be the site of the first crossing diamond design in Oregon.

Project funding


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.

The project was fully funded thanks to a $25 million investment from the 2009 Oregon Jobs and Transportation Act (JTA), a funding package based in part on increases in truck weight-mile taxes, flat fees, registration fees, road use assessment fees, and heavy vehicle trip permit fees.

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.

Collaboration with private contractors

The project team collaborated with several private contractors in 2012 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. Significant grade differences are in store for prime contractor Hamilton Construction. For instance, the new roadway at the top of the southbound I-5 off ramp is designed to rise nearly eight feet higher than the current level.

One of the results of the collaborative meeting with contractors was a staged approach that sets aside a large area for unimpeded construction and builds temporary roadways and ramps, opening up the entire project area for heavy construction.

“Reducing congestion during construction will be quite a trick in such a tightly-developed commercial and residential interchange area,” Leever said. “Our plans call for stages to build the new interchange while keeping I-5 and the local roadways open at the same time.”

Bridge aesthetics

Aesthetic features inspired by the hills and grasses — the natural colors surrounding Phoenix — are in the final design.

The utilization of concrete form liners and different stains and paints presents opportunities to design a bridge with a local look instead of the drab concrete structures common when I-5 was initially built.

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.

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