CHICAGO (CBS) — The plan for an extensive widening of the Tri-State Tollway has some homeowners in Oak Brook concerned, and they’re calling for more details on the project.

A massive wall along the tollway already looms over Joe Scrappo’s back yard, and it could get much closer to his house when the state begins to widen Interstate 294 between Rosemont and Bridgeview.

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Despite the wall, Scrappo can hear traffic on the Tri-State all day long.

“Measure it at 4 o’clock to 6:30, and it’s unbearable,” he said. “You can’t hear yourself on the back of the patio.”

Design and construction of the widening project are still years away, but the $4 billion plan has been approved by the Illinois Tollway board.

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The plan would add one lane in each direction along a 22-mile stretch of I-294 between Balmoral Avenue in Rosemont and 95th Street in Bridgeview.

Scrappo said, if the Tri-State wall moves a few feet closer to widen the tollway, it wouldn’t be so bad, but if it ends up moving 20 feet – as has been proposed – things could get very loud for him and others whose yards back up to the Tri-State.

“The concerns are the unknown,” he said.

Scrappo has lived in his Oak Brook home for more than 40 years, and he said he and neighbors just want some answers, beyond just noise.

“What’s going to happen to the land values? People are ready to move,” he said.

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According to the tollway, construction on the project would begin in 2020, and be completed by 2022.