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The Beauty of Public Projects

by Aug 17, 2021Magazine, Transportation

The Glenn Highway/Muldoon Diverging Diamond Interchange.

Ken Graham Photography.com

A little design goes a long way

Perched in the northeast corner of Anchorage lies a curious piece of infrastructure that serves as a gateway to the City of Lights and Flowers.

Approaching from the north and south, drivers pass under a pair of bridges etched with detailed scales resembling those of a fish. When they aren’t questioning what brought them to the wrong side of the road, crossers east and west might take note of a crimson fence or tasteful landscape elements.

This gateway is the Glenn Highway/Muldoon Diverging Diamond Interchange (DDI): the only of its kind in the state.

Public projects don’t always contain aesthetic design elements, but when they do—like in the case of Alaska’s first DDI—they add an intangible, though intrinsic value to the city and its residents.

But who decides when a roundabout gets a face lift? And what amount of funding is allocated to the beautification of a bridge?

First of Its Kind

In most cases, these decisions lie with Alaska Department of Transportation & Public Facilities (DOT&PF).

“All the planning—whether there was going to be an artistic component or some of the extra landscape features—was decided before by the client [in this case DOT&PF],” says Kelly Kilpatrick, a project manager and transportation engineer with DOWL who was involved with designing the iconic Glenn/Muldoon DDI.

“We developed all the details, all the colors, every design, and basically told the contractor, ‘This is what it needs to look like.’”

The DDI, also referred to as the double crossover diamond, is a fairly recent design to the United States. There are less than 150 completed and currently in use in the Lower 48, though plenty more are in construction.

The Glenn/Muldoon DDI project was first pitched back in 2013 in response to growing concerns over safety and traffic congestion. The DDI was touted as:

  • more efficient and having a longer life span than other redesign alternatives;
  • the least disruption to traffic during construction;
  • and almost $10 million cheaper than other alternatives.

After navigating the usual hoops like preliminary engineering assessments and securing the proper documentation, construction began in spring of 2016 and was completed two years later, funded jointly by state and federal governments.

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Public projects like these take “quite a large team to develop” according to Kilpatrick, from the contractor performing the bulk of the construction to the specialized sub-consultants handling more peripheral details like the etchings of the wall panels. Kilpatrick notes that project management software like Deltek helps keep the process running smoothly along the way.

For the Glenn/Muldoon interchange, DOT&PF’s Request for Proposal already included a recommendation for a landscape architect: Vicki Scuri. As an interdisciplinary artist and designer, Scuri had worked on a variety of similar projects in the past.

There are fewer than 150 double diamond interchanges in the United States; this one is located on the Alabama Gulf Coast.

George Dodd | Dreamstime.com

Scuri partnered with DOWL’s internal landscape architects for the Glenn/Muldoon interchange’s final design.

And Kilpatrick says there were a lot of considerations that went into the design decision.

“When Vicki came up, she and our design team did a site visit in that area. And when we’re choosing artistic elements, we like to take the surroundings into it,” she explains, pointing to the bridge walls that took inspiration from the Native Heritage Center just around the corner.

“Vicki actually went on site when they were making those wall panels, just to make sure they came out just right,” Kilpatrick laughs. “It’s not something that’s typically done up here, but because it was a gateway feature, DOT allowed a little bit more intricacies in those MSE [mechanically stabilized earth] walls.”

The Price of Pretty

While the final products are typically a welcome sight, these projects can still face their share of resistance during the development stage.

“It’s a little controversial because people attribute all these added features as taxpayer money,” admits Kilpatrick. One way that those involved with developing public projects try to combat this is through extensive public outreach campaigns.

Throughout a project’s lifetime, a number of public meetings take place where developers share design renderings and field public opinion.

“There’s special features that help drivers as they go through roundabouts—sometimes they don’t necessarily want them to see through roundabouts because it slows down the traffic. We use landscaping elements a lot to help drivers navigate through the interchange.”

—Kelly Kilpatrick, Transportation Engineer/Project Manager, DOWL

“We have to find that balance of what’s not over the top versus what’s acceptable by the community,” says Kilpatrick. “We try to make them part of that decision process… Because as outsiders, they might see things that we don’t see when we’re engrained in it.”

During the outreach campaign for the Glenn/Muldoon DDI, state transportation officials doubled down on marketing efforts with a variety of social media posts and visual animations to educate the public on the benefits of DDIs.

One of these efforts, in the form of a 30-second video preview reminiscent of a Star Wars intro, even premiered in a local movie theatre.

Form and Function

But in addition to being easy on the eye, there also often exists an underlying function for aesthetic design.

Per the National Academies of Sciences, Engineering, and Medicine’s 2021 Diverging Diamond Interchange Informational Guide: “The DDI constructed on the Glenn Highway at Muldoon Road outside Anchorage, Alaska, applied the symmetrical widening technique and constructed new bridges on either side of the existing bridge. The wide median simplified the crossover design by reducing the crossover spacing. This also allowed large portions of the roadway approaches to be constructed while maintaining traffic on the existing bridge and cross street.”

A roundabout is another excellent example of planning that is both visually pleasing as well as serving an important purpose for society.

Only twenty years ago, Alaska didn’t have a single roundabout in the state. Today, there exists more than forty, with many more in the pipeline.

According to DOWL Transportation Engineer Kelly Kilpatrick, landscaping elements in the center of a roundabout can help drivers better navigate through them.

©Stephen Griffith | Dreamstime.com

The reason? They’re a safer alternative to intersections. And quite simply—they work. Per DOT&PF’s Design & Construction Standards section, several national studies revealed that roundabouts converted from signalized intersections experienced:

  • a 90 percent reduction in fatalities;
  • a 76 percent reduction in injuries;
  • and a 35 percent reduction in crashes overall.

Additionally, roundabouts have been shown to reduce congestion, fuel usage, and long term costs. These findings have led the DOT&PF to adopt a “Roundabout First” policy, which requires designers to submit a written justification for any decision to install a traffic signal instead of a single lane roundabout.

As Kilpatrick explains, the landscaping aspects of roundabouts (which were also implemented in the Glenn/Muldoon interchange) can serve important functions.

“There’s special features that help drivers as they go through roundabouts—sometimes they don’t necessarily want them to see through roundabouts because it slows down the traffic,” she says. “We use landscaping elements a lot to help drivers navigate through the interchange.”

Another big element in landscape planning, Kilpatrick notes, is recognizing the ongoing maintenance needs. For the Glenn/Muldoon interchange, DOWL implemented glare screens to help prevent opposing vehicle direction glare, which also aids vehicles in directing them through traffic patterns.


In terms of obstacles, no two projects are ever exactly alike.

“It definitely varies by project. I would say every project has its own challenges and we tend to adapt to those,” says Kilpatrick.

Though Kilpatrick admits an overarching theme is maintaining the partnerships between the public, the consultant, and the DOT&PF. But rather than viewing this as a challenge to overcome, DOWL approaches it as one of the most important aspects of a project.

And fortunately for DOWL and DOT&PF, the Glenn/Muldoon interchange is simply one of many projects the pair has collaborated on.

“It’s a very long partnership—they’re actually our number one client. We’ve probably got a good dozen or more projects a year with them,” says Kilpatrick.

Some of DOWL’s latest projects include the Windy Corner project along the Seward Highway and the Sterling Highway Milepost 45-60 in Cooper Landing.

“We have to find that balance of what’s not over the top versus what’s acceptable by the community. We try to make them part of that decision process… Because as outsiders, they might see things that we don’t see when we’re ingrained in it.”

—Kelly Kilpatrick, Transportation Engineer/Project Manager, DOWL

Enjoy this story? Check out other in-depth articles in our August 2021 Digital Edition.

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