Construction progress on the 4-mile stretch of Dillon Road/144th Avenue is still slated to be substantially complete by October, but traffic along the major thoroughfare has dropped dramatically since the COVID-19 pandemic has kept people home, which is allowing for more work to take place simultaneously.
The project includes widening the road to four lanes between Zuni Street and U.S. 287, and installing utilities and trails.
Broomfield Capital Improvement Program Manager Kathryn Bergh said this is the city’s largest ever self-funded roadway project with no financial help from state or federal sources. It was planned on a three-year fast track, starting with design in fall 2017.
Originally the project was phased out to 2028 in four phases, according to a Jan. 13, 2015 Broomfield City Council memo. An initial master plan was developed in 2006 for conceptual design of the roadway sections between U.S. 287 and Zuni Street. The plan was refined and revised in 2012.
Originally the project was planned to be phasedin over 12 years, Bergh said, but City Council approved bond funding to get it completed faster because traffic was “overwhelming.”
Construction started in April 2019 on the eastern half of the project from Sheridan Boulevard to Zuni, Bergh said. Shortly after the city amended the construction contract to add the west half, from Sheridan to U.S. 287. Now, all 4 miles are under construction at the same time.
Fast-tracking the project means it will be completed in about half the time, Bergh said.
“Without bond funding and a fast-track schedule, the design and construction would typically take about twice as long, or six years,” she said.
Before Gov. Jared Polis’ stay-at-home order went into effect on March 26, traffic volume on the 4-mile stretch included in the project was 21,199 vehicles a day, Bergh said.
Traffic volume since the order was enacted is down to about 10% of that, or 2,200 vehicles a day, she said, based on her estimates and those of the contractor and consultant.
In fall 2017, City Council approved $40 million in bond funding for the project. Additional water and sewer funds were later added for a total project budget of $42.7 million, Bergh said. It made sense to build in the water lines at the same time as crews worked on widening the road, she said.
The project includes 17 lane miles of roadway widening, Bergh said, and 23 miles of new utilities, including water, sewer, storm drainage, irrigation, electric and fiber conduit.
“It is at least as much a utility project as it is a highway widening project and arguably more,” Bergh said.
Broomfield hired Hudick Excavating, Inc, which is doing business as HEI Civil, as the contractor and Mueller Engineering Co. for the project. They city also hired Ground Engineering, Inc. as a consultant on construction management, inspection and materials testing.
Peak traffic volumes on Dillon/144th, during the morning and afternoon rush hours, include up to 60% “cut-through” traffic, which refers to motorists whose trips start and end outside of Broomfield, Bergh said. Commuters from Thornton, Westminster, and Northglenn use Dillon to travel west to Boulder in the mornings and then to return to their eastern destinations in the afternoon, Bergh said.
By 2040 , traffic volumes along the east end of the corridor near Zuni Street are expected to increase by about 50%, and increase by 75% percent on the west end of the corridor betweenSouth 120th Street and the U.S. 287 interchange, Bergh said. No traffic studies have been done during the pandemic as traffic engineers are working from home.
Dillon/144th is reduced to one lane in both directions for all 4 miles of the project’s scope during construction.
“It is so quiet out here during the day,” Bergh said, which has been “awesome” for the project.
With the lack of traffic, crews are able to do more activities at once in different spots, she said, and while the completion date is still the same, it is nice to have less congestion with which to contend.
“There’s less people on the road impacting construction. It works both ways — we impact travel, but they impact our construction,” she said.
The project also includes upgrading all existing traffic signals and interconnecting them via fiber so the city can control the programming and timing, Bergh said, which will help with traffic flow. Crews also added a southbound right turn lane at Zuni and second southbound left turn lanes on South 120th Avenue and Lowell Boulevard, and are adding a frontage road at Aspen Street for residents who have driveways that feed to Dillon and converting the three-way intersection to four-way at Aspen.
The project also includes building a 10-foot-wide concrete trail on the south side of Dillon that will run 2 miles from Sheridan to Rock Creek Trail, west of U.S. 287. It also includes, at a $2 million price tag, burying 2 miles of power lines on that south side of 287, Bergh said, which will afford a better view of the mountains.
Crews are currently prioritizing drainage improvements because of flooding concerns.
“It’s not a safety concern to the public,” Bergh said, “but you don’t want to have big erosion control problems.”
