The Cole County Commission is on board with Jefferson City officials' pursuing a roundabout at the intersection of Clark Avenue and Dunklin Street within the next few years.
Jefferson City Public Works Director Matt Morasch and Jefferson City Engineer David Bange told commissioners Tuesday this would be a cooperative project, with the county using money from the city and county half-cent capital improvement sales tax.
The County Commission gave its approval during its regular meeting Tuesday.
Earlier this month, the Jefferson City Public Works and Planning Committee approved city staff's request to direct engineering firm Bartlett & West to design a roundabout for the Clark Avenue and Dunklin Street intersection.
The initial cost to place a roundabout at the intersection — $1,719,812 — is higher compared to the initial cost to place a signal there — $1,307,635, Morasch said.
However, the cost over 20 years is significantly different between the two, with the roundabout being the cheapest option. Over a 20-year period, the roundabout would cost $1,016,833, while the signal would cost $3,783,056.
The large difference comes from the loss in service and delay costs, along with replacement signal equipment.
The loss in service and delay costs for the signalized intersection option are nearly three times the costs for a roundabout, Morasch said. Replacement signal equipment would also cost the city about $350,000 over 20 years, he added.
If Jefferson City builds a roundabout at that intersection, Morasch said, the city would have to acquire a nearby building currently being rented and used as a church.
In November 2017, the Jefferson City Council approved a $126,852 contract with Bartlett & West to conduct a traffic study on the Clark Avenue interchange and corridor, from East McCarty to Hillcrest streets, and determine feasible solutions.
The study also reaffirmed roundabouts would work at the intersection of U.S. 50 and Clark Avenue, which currently is maintained by the Missouri Department of Transportation.
News Tribune reporter Nicole Roberts contributed to this article.