WILLMAR -- A proposed highway redesign would reduce crashes at the Business 71/County Road 24/23rd Street intersection west of the Kandiyohi County Health and Human Services Building.
The design would prohibit east-west traffic on 23rd Street and County Road 24 from crossing the northbound and southbound lanes of Business 71 and eliminate an unusually high number of right-angle intersection crashes.
The design was preferred among nine possible solutions studied by a consultant and discussed for a number of months by representatives of the City of Willmar, Kandiyohi County and Minnesota Department of Transportation.
Jon Henslin, design and traffic engineer with the MnDOT District 8 office in Willmar, cited a number of reasons why the group representing the three entities preferred Alternative No. 3, as it's known in a report by CH2M Hill Inc. of St. Paul, the consultant hired by the three entities to study the intersection.
"We thought it was the best one because it was easiest and shortest to implement. The crash rate was very low, no crossing conflicts, and minimal cost,'' he told a Thursday evening meeting of the Willmar City Council's Public Works/Safety Committee. Two county commissioners and other council members also attended.
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A solution similar to No. 3, but which included U-turns in the median, was estimated at about $800,000.
"There is no right-of-way acquisition and the opportunity to implement the U-turns could be done in the future if No. 3 causes problems at the signal at Civic Center Drive. We could add a U-turn there.''
Henslin said No. 3 was estimated at $180,000. Another solution was a roundabout, which was estimated at about $1.5 million. A grade separation (bridge) with restricted access was estimated at $2 million and an interchange was estimated $5 million to $10 million.
Henslin said approval from the city, county and MnDOT is needed to proceed at least through the design phase in order to construct the project in 2010, and to get funding commitments from the three entities.
Henslin said no decision has been made on funding, but he said the entities have already set a precedent by each paying one-third of the consultant's cost. He said the entities recommend the same formula be continued for paying for the project.
After the presentation by Henslin and Howard Preston of CH2M, the committee voted to recommend the council support No.3 and proceed with the preliminary design work.
CH2M was hired after a 2006 road audit identified potential short-term and long-term modifications to reduce crashes. The stop signs were upgraded to MnDOT recommendations, a one-way sign was added, and the radius was increased of the right-turn lane in the southwest corner of the intersection.
However, none of the upgrades significantly reduced crashes.
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In 2007, flashing stop signs were added and the intersection was evaluated.
"We didn't see the drop in accidents we were looking for,'' said Henslin "One of the things we also did was all three entities got together and hired a consultant to do a follow-up study to that safety audit, and that basically was a feasibility study of the more expensive-type improvements that were listed in the study.''
Preston said a fairly exhaustive process was used to identify the best strategy.
Preston said the intersection has a crash frequency of six crashes per year, which was unusual, compared with two crashes per year, based on a history of thousands of other intersections across the state, and has one injury crash per year, almost four times higher than similar intersections.
Also, 61 percent of the crashes -- an unusually high percentage -- are right-angle crashes involving a northbound or southbound vehicle and an eastbound or westbound vehicle.
"At this type of intersection we would tend to see an order of about 25 percent or 26 percent being right-angle crashes,'' said Preston.
He said the geometry of the intersection, such as the varying width of the median, violates drivers' expectations. He said the proposed design would eliminate most crashes.
"The safety data says, looking at these kinds of locations elsewhere, we would expect about 80 to 90 percent of the crashes to be eliminated,'' Preston said.
