$27M upgrade set for Hwy 22 north of Mankato

Mark Fischenich, The Free Press, Mankato, Minn.
·7 min read

Mar. 20—MANKATO — Passing lanes added, two dangerous intersections slated for complete makeovers, and numerous other upgrades — Highway 22 between Mankato and St. Peter is set for a significant transformation in 2024.

The Minnesota Department of Transportation this month budgeted $26.9 million for the 7.5-mile section of highway that carries more than 10,000 vehicles per day from the northeast side of Mankato to the south end of St. Peter — almost $12 million more than originally planned. The project now includes a roundabout at the entrance road to Kasota, a novel intersection to ease access and minimize crashes at the intersection of Highway 22 and North Riverfront Drive, and turn lanes at every public intersection.

The improvements are needed now based on travel delays and, especially, crash rates, said MnDOT project manager Forrest Hasty. With traffic in some parts of the segment projected to grow to 16,000 in the next couple of decades, congestion and crashes would become even more severe without the planned upgrades.

"It is the highest-traveled two-lane roadway in the district," Hasty said, referring to MnDOT's District 7, which covers south-central Minnesota and stretches southwest past Worthington to the Iowa and South Dakota borders.

By the end of the 2024 construction season, the section of Highway 22 won't be strictly a two-lane any longer. A third lane will be constructed, mainly to add left-turn lanes but also to allow for passing lanes for both northbound and southbound traffic midway between Mankato and St. Peter.

Along with the roadwork, MnDOT is working with the Department of Natural Resources to add a $3.4 million bike trail from St. Peter to the Sakatah Singing Hills Trail in Mankato.

"So this is easily a $30 million project," Hasty said.

Picking a plan

When MnDOT studied the corridor, including seeking input from road users, it considered a variety of options ranging from simply repaving the segment to turning it into a four-lane highway. The design chosen was based on public preferences, cost considerations and — most of all — a desire to reduce travel times and improve some ugly crash statistics.

"The pavement's not the best, but what's really driving this is the crash issues and the delay issues," Hasty said.

Some might have preferred an expansion to four lanes, but that wider corridor would have meant an extraordinary amount of disruption for people who live or do business on Highway 22. Hasty guesses it would have pushed the project cost close to the $100 million mark, even without accounting for the expense of right-of-way acquisition.

"We'd be buying homes, we'd be buying businesses," he said. "And that's never a good thing."

It's also more difficult to justify the cost of creating a four-lane highway when a four-lane expressway between Mankato and St. Peter already exists just on the other side of the Minnesota River — Highway 169.

"I think what we're doing is the right thing," Hasty said.

Three lanes

Much of the route will still have one thru-lane in each direction even after the project is completed. The exception will be in the middle portion of the segment where mile-long passing lanes are likely to be added to allow people to get around slow-moving vehicles.

For southbound traffic stuck behind a pokey driver, the chance to safely pass will begin near the asphalt plant about a half-mile south of the Chankaska Creek Winery. The passing lane for northbound traffic will be just to the south of where the southbound passing lane ends.

"You're not going to see yourself behind a whole platoon of traffic as you do today," Hasty said.

It appears the passing lanes are much-needed, but some additional traffic counts have been ordered to make sure.

"As an engineer, I have to see justification before I can spend millions of dollars," he said.

Elsewhere, the third lane will allow for the addition of left-turn lanes and longer turn lanes — left and right — so turning traffic can wait to decelerate until they've moved into the turn lane, which reduces delays and the danger of rear-end crashes in the thru-lanes.

MnDOT found there were 76 crashes over five years on Highway 22 from just north of Mankato to the Minnesota River crossing on the south side of St. Peter, not counting intersection crashes.

The frequency of crashes is twice the statewide average for similar two-lane highways on the southern segment — from the intersection of North Riverfront Drive to 480th Street, commonly called Squirrel's Nest Road. It's triple the statewide average on the north end — from St. Peter to Pearl Street, which leads to Chankaska Creek Winery.

Along with the additional and improved turn lanes, lighting will be added at intersections, some driveways will be combined, and driveway approaches will be made less steep.

Fixing intersections

Although every junction is slated for improvements of some sort, two bloody intersections are getting the most attention.

It will be a roundabout at Le Sueur County Road 21, which connects Highway 22 to Kasota on the west and serves as something of an eastern bypass of St. Peter for drivers looking to head east on Highway 99. So drivers will need to slow from highway speeds to roundabout speeds in that area.

In return, there's expected to be a dramatic reduction in a crash rate twice what's typical for similar intersections. Of the 16 crashes at County Road 21 over a five-year period, nearly two-thirds were dangerous right-angle collisions and another 13% were head-on.

At North Riverfront Drive, also known as Blue Earth County Road 57, the crash-rate is more than triple the average, and over half of the collisions are right-angle crashes. Most of the trouble there involves traffic on Riverfront making a left turn to northbound Highway 22, with traffic backing up significantly during afternoon peak-travel times. The solution there is a "continuous T" intersection.

Hasty said he believes it will be the first intersection of that design in District 7. It involves separating the northbound and southbound lanes of Highway 22 with a broad median and constructing an acceleration lane in the median for drivers turning left from Riverfront onto northbound Highway 22. By doing that, those drivers will need to find a gap in oncoming traffic only in the southbound lane of Highway 22 rather than gaps in both the southbound and northbound lanes of the highway.

In addition to improved safety, the new intersections are expected to reduce delays faced by drivers trying to access the highway at those intersections. The Kasota intersection already grades out as "D" during the morning rush hour and at an "F" in the afternoon on an A-F scale. The North Riverfront intersection has a "D" grade for the afternoon rush hour, and the grades for both intersections are projected to get worse as traffic levels rise.

The planned improvements to the highway, including the intersections, are projected to reduce crashes by 78% and delays by 71%. Under MnDOT's complex formula for monetizing the societal cost of crashes and delayed travel time, the project has a benefit-to-cost ratio of 10.6-to-one.

A ratio of 4:1 is the threshold of a viable project, according to Hasty: "10.6, you're hitting it out of the ballpark."

Trail route pending

The specific location of the bike trail will be decided in the next six months following detailed conversations with property owners. While the trail is to roughly follow Highway 22, that doesn't mean it will be immediately adjacent to the vehicle traffic. The path will be at least 25 feet from the highway, and large portions of it could be out of sight of the road because of various barriers that might make it less intrusive and less expensive to construct it farther away from the highway corridor.

"We'll be having a lot of one-on-ones with property owners," Hasty said.

For nearly a decade, the DNR has been attempting to negotiate a route for the trail, which will be a piece of a much longer trail planned for the length of the Minnesota River Valley. But the DNR doesn't have the authority to condemn land and has struggled to create a continuous route from St. Peter to Mankato. By connecting it to the Highway 22 project, MnDOT could condemn property if that's necessary to fill one or two gaps in the route.