BRIGHAM CITY — UDOT’s 1100 South/U.S. 91 DDI project in Brigham City has been selected as a Top 10 finalist in America’s Transportation Awards, sponsored by the American Association of State Highway and Transportation Officials (AASHTO).
The northern Utah project is competing against projects from eight other states to win first place in the competition, which includes a cash prize that will be donated to a deserving charity in Utah.
An aerial shot of the project. White substance is geofoam
“This Top 10 project is one more example of why UDOT has a reputation for being a national leader in quality and innovation,” said UDOT Executive Director Carlos Braceras. “I extend my congratulations to everyone who is associated with the project.”
Braceras suggested that anyone who would like to support the Brigham City project in the competition for best transportation project in the United States can participate in the voting for America’s Transportation Awards. “You can vote as many as 10 times per day per email address,” Braceras said.
Voting is currently underway online for the People’s Choice Award in the America’s Transportation Awards competition. To vote, go to http://nominate.americastransportationawards.org/Voting.aspx.
Voting will continue through Sept. 11.
A worker helps place geofoam, which helped “float the DDI” on geotechnically difficult terrain
The UDOT project is among 10 finalists in the competition. It is competing against projects from Florida, Kentucky, Indiana, Texas, North Dakota, New Mexico, South Carolina and Montana.
The Brigham City project qualifies in two top categories. One is the National Grand Prize, honoring the nation’s top transportation project as determined by a panel of industry experts and professionals. The other is the People’s Choice Award, which is voted on by the public through online balloting. The winner in each category receives a $10,000 donation to a charity or scholarship fund.
In order to be selected as a Top 10 project, it first had to be selected as a regional winner. The project won in the “Under Budget” category for an innovative design that could have cost as much as $100 million, but through out-of-the-box engineering and sensitivity to geological issues around the area, cost only $14 million.
With more than 20,000 vehicles a day — many of them trucks — originating throughout the region, this old, inefficient interchange was reducing the flow of the economic lifeblood of local communities to a trickle.
The 40-year-old interchange would frequently clog when vehicles at its ramps tried to enter the traffic flow. The predominant west to south-bound traffic on US-91 was so steady during the day that it was nearly hopeless for other movements to occur. This prompted risk-taking by trapped motorists at the ramps, and frequent crashes when they did. Regional special events, like local university football games, would bring traffic to a complete halt.
UDOT traffic planners needed a solution, but the answer was elusive. Soils adjacent to the Great Salt Lake were saturated by surface groundwater, making the interchange increasingly unstable. Engineers wondered how to upgrade it without a massive redesign to accommodate the increasing pounding from trucks. Similar rebuilds had cost upwards of $100 million – prohibitive under state budgets.
The answer: innovate. Engineers used an innovation to solve the water issue — geofoam — which allowed the new interchange to “float” on soggy soils. Another innovation — advanced bridge construction — replaced the interchange’s old bridge over I-15 while adding a completely new span in a little more than 10 months. Finally, the innovative diverging diamond traffic pattern was added to the design to solve the problem of congestion and safety.
The result of all this innovation was an efficient interchange that allows all traffic movements to occur safely and congestion-free, and all for less than $14 million.
The first car goes through the Brigham DDI.
The America’s Transportation Awards competition is co-sponsored by the American Association of State Highway and Transportation Officials (AASHTO), the American Automobile Association (AAA) and the U.S. Chamber of Commerce. The top two national winners will be announced in September at the AASHTO Annual Meeting in Chicago.