Guides synthesize experience, current thinking on innovative intersection and interchange solutions

November 20, 2014

Four recently released informational guides about alternative intersection and interchange solutions, developed as part of the Federal Highway Administration’s (FHWA) Every Day Counts initiative, synthesize experience and current thinking nationwide on best practices for these innovative forms.

The guides – one focusing on diverging diamond interchanges and the others on displaced left turn, median U-turn and restricted crossing U-turn intersections – were introduced during two late August webinars. Each webinar drew 600 to 700 attendees, who heard overviews about the guides.

The webinars are just the beginning of efforts to raise awareness about the guides and focus on specific topics they address, says Andy Daleiden, PE, an associate engineer with Kittelson & Associates, Inc. (KAI), which was part of the team that developed the guides. The team included the Virginia Tech Transportation Institute, Wayne State University, Parsons Brinckerhoff, Chris Cunningham and Bastian Schroeder.

The guides expand on chapters from the 2010 FHWA Alternative Intersections/Interchanges Informational Report. The guides became part of the second phase of Every Day Counts because the innovative intersection and interchange forms were gaining momentum and more was being learned – and, in some cases, more data still is needed – about their operational, safety and other benefits, Andy says.

The goal, he adds, is to provide practitioners with “solid guidance going forward. The idea is that you have a benchmark for the profession to use for the next couple of years, and we’ll learn more through research and the guidebooks will be updated.”

Launched in 2010, Every Day Counts responds to the nation’s challenges in terms of vast infrastructure needs, an increasing population and declining public budgets. The initiative encourages innovative transportation technologies that can improve safety, shorten project delivery, save money and protect the environment.

Every Day Counts “emphasizes shrinking the timeframe to take something from new and innovative to routine and mainstream,” says Jeff Shaw, intersections program manager for FHWA’s Office of Safety.

The guides on diverging diamond interchanges and displaced left turn, median U-turn and restricted crossing U-turn intersections are the result of feedback from transportation leaders at the local, regional and state levels indicating that the alternative forms have been working “exceptionally well.” In addition, they address multiple aspects of Every Day Counts, “but first and foremost intersection safety,” Jeff says.

There was definitely a sense that these (forms) were becoming more common. We saw an opportunity through the guides to synthesize the experience and current thinking nationwide on best practices. But it’s still a dynamic time, and there’s not a cookie-cutter design approach. We wanted to capture that variety, how that translated to certain project outcomes and provide information so that practitioners could make appropriate decisions at the project level. This will continue to be dynamic. The information in the guides is the best of what we know at this time, and we expect local and state agencies will continue to build on their experience and there will be more to learn from.

In the coming months, FHWA intends to hold additional webinars that focus on specific topics within the guides, Jeff says. Attendees of the initial webinars indicated, for example, that they were interested in future presentations about how to conduct capacity analyses on the intersection and interchange forms, and strategies to integrate pedestrian and bicycle facilities.

You can access and/or download the four guides here.

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