Roundabouts recommended
March 04, 2010 · Jake Krob

A consultant's final report to the City of Mount Vernon indicates there's basically no cost difference between roundabouts versus signals on Hwy. 30. And that consultant recommends the city choose the roundabout alternative.

In a special city council meeting last week - with just three council members present - Erv Mussman of Cedar Rapids-based Shive-Hattery presented the firm's final report on ways to improve the Hwy. 30 corridor in the city. The report recommends a three-lane urban Hwy. 30 (the third lane as a turn lane) and roundabouts at the intersections with 10th Avenue and Hwy. 30. Shive-Hattery also estimates cost of such work at about $4.5 million, slightly less than an urban highway with traffic signals at Hwys. 30 and 1.

Council members Marty Christensen, Neil Rud and Diane Hoffmann discussed the report during about a one-hour session. Not present were mayor Paul Tuerler and council members Slaton Anthony and Scott Peterson. In the end, the three asked for a more detailed cost breakdown. And they recognized that the big next step for the city is to select an alternative and decide whether or not to move forward with more detailed design plans.

Last October, the council commissioned Shive-Hattery to work on proposals (at a cost not to exceed $45,500) for improving the Hwy. 30 corridor in the city. Three alternatives were shared earlier this year - alternatives that remain in the final report by the firm. All include widening Hwy. 30 in the city and providing some kind of intersection improvements. Per Iowa Department of Transportation standards, stoplights are not warranted at the Hwy. 30/10th Avenue intersection. The options, and their cost estimates, are:

1 - A rural three-lane highway (with no curb-and-gutter) and signals at Hwys. 30 and 1: $3.13 million.

2 - An urban three-lane highway (with curb-and-gutter) and roundabouts at Hwys. 30 and 1 and Hwy. 30 and 10th Avenue: $4.5 million.

3 - An urban three-lane highway (with curb-and-gutter) and signals at Hwys. 30 and 1: $4.56 million.

The final report also includes cost estimates what are titled "interim" projects. Mussman said that would only involve making improvements to the Hwy. 30/10th Avenue intersection. He pointed out that the intersection is a concern, particularly for the school district as 10th Avenue leads to the district campus. According to crash history data in the Shive-Hattery report, there were 18 crashes there from 2001 to 2007, 11 of which were rear-end collisions.

The following cost estimates were given to just improve the Hwy. 30/10th Avenue intersection for the three alternative styles of highway:

1 - $450,000

2 - $690,000

3 - $620,000

In early January, the city was notified that it has been approved for $373,419 in Iowa Clean Air Attainment Program (ICAAP) grant funds to improve the Hwys. 30 and 1 intersection. Specifically, the application was for a signalization project at the intersection, but Mussman said the funds could be used for a roundabout.

City administrator Mike Beimer said the money hasn't been received, and the city also hasn't received a contract for the use of the funds.

"There's always the outside chance that we may not get the funds," Beimer said.

Mussman said that's one reason for the city to consider approving one of the next steps - engineering drawings for an ultimate plan of corridor improvements. Additionally, he said such a plan could be used to apply for other funding sources. He pointed out to the council that designing an ultimate plan doesn't mean the project has to be completed all at once, but that it could be used to identify pieces to complete as funding warrants. Additionally, he said if planning gets under way and the chosen alternative is not what the city wants, it could change course.

What alternative the city council will approve was unclear at last week's meeting.

What was clear was that the council wants a bit more information.

Christensen said he'd like to see a more detailed breakdown of the various cost estimates. Rud said that could be done by percentages. The council desires to know, for instance, what the cost is for the three-lane urban work, each of the roundabouts, and signals at Hwys. 30 and 1.

Hoffmann said she was "somewhat disconcerted" that the cost estimate for roundabouts is actually slightly less than the option of signals. She pointed out that in preliminary reports the roundabout option was more costly.

Mussman said some discrepancies were found in the per-unit costs related to concrete in previous estimates. He also said that the biggest cost issue is the urbanization work, not in the style of intersections.

In another cost-related discussion, Beimer asked about discussions with the school district to participate in the 10th Avenue intersection improvements. Hoffmann said she'd imagine the mayor would be having those discussions with school leaders. Personally, she said, "the school should be considering ... partnering with the city."

"It's logical to do that," Rud added.

There were also some questions about the specific options presented in the final report.

Mount Vernon resident Robert Caldwell wondered about an option discussed before. Although not specific in the alternatives, there's the possibility of urbanizing Hwy. 30, putting a roundabout at 10th Avenue and signals at the Hwy. 1 intersection. Caldwell said if the signal is red, and traffic is stopped, there will be no movement through the roundabout. He said if roundabouts are the option, they should be placed at both intersections.

Mussman said he's "pretty confident" it would work if there were a roundabout and a signal.

Tim Simodynes of the Iowa Department of Transportation agreed. He said the intersections are far enough apart for it to work.

Hoffmann said people have asked about how large machinery, such as farm equipment, would get through a roundabout.

Simodynes said the DOT has videos of combines going through such an intersection. He said if the wheel base is such that the equipment can travel on typical roadways, they can do so through roundabouts. He said the roundabout at Hwys. 30 and 1 would actually be wider than a typical highway and would have a sloped curb that large machinery could go up on.

Beimer, referring to an area near the Hwys. 30/1 intersection as being one of two possible sites for a new fire station, wondered about the impact of signals versus a roundabout when it comes to getting firefighters to the station and trucks from the station.

Simodynes said signals can be equipped with devices to turn the light green for responders. Roundabouts, he said, reduce crashes and thus benefit the fire department by reducing calls.

City engineer Dan Boggs said regardless of how the intersection is treated, the response time for a fire station located in the southeast corner of Hwys. 30 and 1 is the longest compared to the other location considered.

The three members of the council last week took no action on the final report from Shive-Hattery.

Mussman urged action on determining a preferred alternative and moving forward with more detailed design. He said he didn't know the cost of such design work.

And, he said, roundabouts "most thoroughly address the issues in the corridor" area.