Construction (and traffic delays) starts on 146th and Allisonville interchange roundabout

It could be a painful six weeks for daily commuters on Allisonville Road and 146th Street in Hamilton County.

The first phase of the $44 million intersection reconstruction has begun, with lane closures both ways causing traffic back-ups.

One of two through lanes in each direction is now closed on 146th Street and one of two left turn lanes in both directions on Allisonville are closed.

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County Highway Director Brad Davis said the restrictions, around the clock, will last through June, including the 35 mph speed limit. After that both through lanes on 146^th will open but left turns won’t be allowed in either direction until the end of the year.

“That should help east-west flow a lot,” Davis said. Nearby alternative routes in those directions are few because access is limited to bridges that cross the White River at 116^th Street and State Road 32, he said.

Allisonville Road’s restriction to one left turn lane will remain after June.

Davis said the changes have caused back-ups but workers are monitoring and “tweaking” the length of traffic signals to keep vehicles moving.

“We are keeping an eye to see what works best at different times of the day,” he said.

Construction crews are removing center concrete medians and preparing to put down temporary pavement, as well as utility relocation work in the right-of-way.

The county is building a roundabout and overpass intersection and widening the White River bridge.

The project is expected to be finished in the summer of 2025.

Drivers should expect more headaches before then. Next year, Allisonville Road will be completely shut down from March through May, Davis said.

Call IndyStar reporter John Tuohy at 317-444-6418. Email at john.tuohy@indystar.com and follow on Twitter and Facebook.