Roundabout construction project on US-18 on track to begin in 2026
By Steve Van Kooten
On the evening of Jan. 25, as the rain trickled down the pavement and mixed with the wet slush in the City Hall’s parking lot, three representatives from the Wisconsin Department of Transportation (DOT), JT Engineering and DAAR Corporation hosted a public information session for the scheduled roundabout construction on US Highway 18 in Prairie du Chien.
The Iowa Street and Wisconsin Street intersections with US-18 will transform into roundabouts to stem traffic concerns. Construction will include a length of Highway 18 from Blackhawk Road through Wisconsin and Iowa Streets to a point several hundred feet South of the Iowa Street intersection.
“This project was strictly driven by need,” Jill Fehrman, Project Coordinator for DAAR, said.
Jed Munroe, Consultant Project Coordinator for JT, presented crash data, which he said established a need for alternative traffic control at both intersections. From 2014-18 a DOT study recorded 39 crashes between the two intersections with 15 injuries. A subsequent study conducted between 2018-22 recorded 51 crashes between the intersections with 16 injuries. The severity of some of the crashes and increased number of incidents were considered when weighing improvement options.
“The traffic is growing, which is probably what is resulting in the additional crashes. It’s kind of symptom of how things develop over time,” Fehrman added.
Munroe said the DOT vetted multiple options, which included the installation of traffic signals, before single-lane roundabouts at each intersection were selected as the best solution.
The project was divided into three phases: the removal of the curb and placement of temporary pavement at the US 18 and Iowa Street intersection, construction of the US 18/Wisconsin Street roundabout and, finally, the construction of the US 18/Iowa Street roundabout.
Munroe stated the project’s contractor was required to maintain at least one access point for businesses and residences affected by the project at all times. Businesses in the area include the Waterfront Hotel and the Prairie du Chien Area Chamber of Commerce among others.
A release from the project team noted new permanent right of way and easements would be required due to the widening of the intersections during construction. These designs were not finalized at the time of the information session.
Munroe detailed the size of the proposed roundabouts, which were expected to measure 120 feet at the Wisconsin Street intersection and approximately 130 feet at the Iowa Street intersection. For comparison, Munroe said the corresponding intersections on WI-35 were 165 feet and 175 feet respectively. His measurements included the apron, traffic lane, barriers and sidewalks/pedestrian areas.
Along with the roundabouts, other proposed improvements include storm sewers, city utilities, lighting, Americans with Disabilities Act (ADA) compliant curb ramps and the preservation of accommodations for oversized and overweight (OSOW) vehicles. Both streets have been used as secondary routes for oversized vehicles, according to Fehrman.
“One of the interesting things about this project is there’s a lot of OSOW vehicles coming from 35 and 18,” Munroe said.
As part of the designs for the roundabouts, the team planned 70 feet wide “truck aprons” to account for the high volume of large vehicle traffic. Aprons are the cement circles that occupy the center of a roundabout that prevent traffic from driving through the area.
“If you watch how large trucks move through the intersections, back tires have to go on a lot of them,” Fehrman said in reference to truck aprons. “So they make them thick enough so it doesn’t damage them.” She also said the apron at Wisconsin Street is planned as a flat, cement circle with no installed vegetation or landscaping while a small plant area has been tentatively planned to occupy a portion of the Iowa Street apron.
During Stage Two, Wisconsin Street will be closed to through traffic. A detour will divert traffic South to US-18 and then backtrack up the highway to the Iowa Street intersection. “It’s like four miles. Is it perfect? No, but it’ll be relatively short,” Fehrman said.
During Stage Three, Iowa Street will be under construction one half at a time to allow traffic to still utilize a lane to enter Wisconsin.
As the roundabouts are constructed, portions of the corresponding street both East and West will be re-constructed to craft lane drops and traffic flow improvements to accommodate the new structures.
Munroe mapped out a tentative schedule for the project, which will include the submission of environmental and preliminary roadway design in March 2024, real estate negotiations in the Fall or Winter, final planing in August 2025 and construction between the Spring and Fall of 2026. Munroe stressed the timeline was not definitive and said the construction could last through October 2026.
The Wisconsin DOT and the project team have requested written comments, which can be submitted until Feb. 9, 2024. Comments can be emailed to John.bainter@dot.wi.gov or mailed to Wisconsin Department of Transportation, 33550 Mormon Coulee Road, La Crosse, WI 54601 Attn: John Bainter.