South Iowa News

Ottumwa was awarded $500,000 from an Iowa Department of Transportation grant to renovate and improve an intersection in their jurisdiction that has a high rate of accidents, and a roundabout might be the answer.

The city council heard a presentation for a redesign that includes that technique.

“Roundabouts are a very safe option when we're trying to make our road safer,” Shive Hattery Design Engineer Justin Campbell told the council. 

He shared a graphic that showed the statistics when a town converts traffic signals to stop signs or stop signs to roundabouts. 

“We can see here, from converting a signal single lane to a roundabout, you can see … basically a 78% crash reduction factor,” Campbell said. “That's very high for changing intersection control types. And on the bottom, you can see that from the Highway Safety manual that we also use for selecting intersection types, I believe, 99% crash reduction in all types.”

Ottumwa was awarded $500,000 from an Iowa Department of Transportation grant to renovate and improve an intersection in their jurisdiction that has a high rate of accidents. The city chose the intersection of Albia Road and North Quincy avenue, which has had 13 crashes in the last five years. 

Campbell explained how roundabouts are made and how they can improve traffic and pedestrian safety and decrease accidents and improve traffic flow. The proposed roundabout, like all generic roundabouts, would have a circular land connecting the three points of the “T” intersection. It will incorporate pedestrian crossings, island splitting and directing each lane, and a truck apron in the center island that reduces curb collisions and improves maneuverability for larger trucks or trailers.

The graphic he presented shows why they are safer.

“When you have your typical four-way intersection, you can see there are 32 conflict points,” Campbell said. “That's any time a car can it's either going through an intersection or making a turn where they could have a conflict with another vehicle. Again, in a typical ’T’ intersection you'd have nine … but with a four-lane roundabout, you would have only eight. So fewer conflict points lead to fewer crashes.”

The project will also include new lighting and landscaping on the islands. The total cost is estimated at $711,000, most of which is covered by the IDOT grant and the rest will be funded through local avenues. 

The project is estimated to take 135 working days, or the majority of the summer construction season. 

The council is putting the project out to bid this month so that construction can begin around May and can hopefully be finished by September.