MARION — Commuters who drive County Home Road might be detoured starting next month as construction begins on building two roundabouts in place of four-way stops.
Construction on County Home Road is scheduled to begin April 6, and will go from about Interstate 380 to Highway 13. The intersections at C Avenue extension and at North Alburnett Road will be replaced with roundabouts.
With 8,000 vehicles a day on County Home Road, officials with the Linn County Secondary Roads Department know residents will be inconvenienced. But they hope the benefit outweighs the temporary disruption.
“Five to 10 years down the road, we can compare data (from the Department of Transportation) to previous years and see if accidents have decreased,” said Garret Reddish, assistant engineer with the Secondary Road Department.
Reddish said that even if there is the same number of crashes, the severity decreases with roundabouts. “They turn into fender benders versus T-bone (crashes) or severe injuries,” he said.
Signs will be posted leading up to roundabouts advising drivers to reduce their speed to 20 mph through the roundabouts.
The rest of County Home Road will receive an upgrade. Turning lanes and paved shoulders are expected to make the road safer altogether, Reddish said.
During peak commuting hours, traffic on County Home Road is likely to be backed up now at these intersections, Reddish said. With high traffic counts and 55 mph speeds on the road, the County Secondary Roads Department thought roundabouts would be a good alternative to four-way stops.
The contractor on the project is Horsfield Construction of Epworth, for a cost of $7,934,357. The contractor has 240 working days to complete the project, not including weekends or bad weather days, which means the project could be completed any time between October or spring 2021.
Only one roundabout will be constructed at a time to keep either the C Avenue extension or North Alburnett Road intersections open to traffic.
Redding said signs will be posted before construction begins and throughout the work to alert drivers to detours.
Reddish knows roundabouts in Eastern Iowa aren’t popular with residents, but the county roundabouts will be built for high-speed traffic — unlike Marion’s urban roundabouts, he said.
“They’re imagining a city roundabout in the middle of the country, and that’s not the case,” Reddish said.
Roundabouts with high-speed approaches typically feature signage and pavement markings far in advance, as well as a design that more obviously channels the lanes.
The county does not have plans at this time to build more roundabouts on county roadways, but Redding said he could see four-way stops replaced with roundabouts when intersections need repairs in the future.
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