Jefferson City is considering placing a roundabout at the intersection of Clark Avenue and Dunklin Street within the next few years.
The Jefferson City Public Works and Planning Committee approved city staff’s request to direct Bartlett & West to design a roundabout for the Clark Avenue and Dunklin Street intersection Thursday morning.
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, Public Works Department Director Matt 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 the 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.
The Clark Avenue project is listed as a joint Jefferson City and Cole County project under the half-cent capital improvement Sales Tax G for 2017-22, Morasch said. He plans to present the proposal to the Cole County Commission this month.
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 is currently maintained by the Missouri Department of Transportation.