The state is gearing up to expand Interstate 270 to alleviate rush-hour traffic congestion between Manchester Road and Interstate 44.
And while some Des Peres and Kirkwood residents along the corridor may get a sound wall to help reduce traffic noise, others will not.
The additional lanes are needed because of significant backups on the highway during morning and evening commutes, said Kristy Yates, area engineer for MoDOT.
The plan calls for an additional southbound lane from Dougherty Ferry Road to Interstate 44 and a new northbound lane from I-44 to Manchester Road.
Work on the $12-million project is not expected to begin until spring. But officials have already conducted studies of 16 areas along the corridor to determine whether sound walls were warranted under federal guidelines.
Yates said officials took measurements in numerous locations and at various times of day. The decibel levels were then used to make predictions on future noise levels.
Of the 16 sections studied, only four are being considered for sound walls, Yates said.
In some neighborhoods, a sound wall was not deemed cost effective. In others, topography or other reasons would prevent a wall from sufficiently reducing decibel levels, Yates said.
Debi Postal and neighbors in her subdivision in Des Peres got letters from the state saying their neighborhood would not qualify for a sound wall because it would cost far more than $30,000 per property, the limit set by the guidelines.
Postal was disappointed, saying traffic noise had increased considerably since she moved into her home 13 years ago. She was concerned that it would get worse.
“It can be really loud,” she said, adding that she was worried home values would be affected. “In the mornings and evenings it’s probably the worst because of high traffic. It’s annoying."
MoDOT representatives and officials from Burns and McDonnell, the engineering company that conducting the sound studies, will be on hand to discuss their findings with residents during an open house between 4 p.m. and 7 p.m. Wednesday at .
About 500 letters were sent to affected homeowners in Des Peres and Kirkwood, Yates said. About half of the homes in the study areas were not eligible to receive sound walls, she said.
The four areas that might be eligible will be studied further. If officials decide they meet all the federal criteria, homeowners will get a chance to vote on the issue.
The department of transportation plans to hold public meetings in November to discuss the overall impact of the project, including timetables and scheduled lane closures.
The project includes permanently narrowing all lanes of the highway in the corridor to 11 feet from 12 feet. Yates said that was due to railroad bridge columns and the Marshall Road overpass, which will not be replaced. In addition, some of the rock bluffs just north of I-44 will be removed.
Work is expected to begin in the spring and be completed in December 2013.