By Sheila McLaughlin
The Cincinnati Enquirer

From Euclid Road in Kenwood to Deerfield Road in Blue Ash, a 5.2-mile, $10 million stretch of sound barrier walls went up along busy Interstate 71 in 1994 as part of a federal mandate to reduce noise along expanding highways.

They were some of the first in Ohio, and the state's most extensive project at the time.

For the most part, the barriers were effective, state transportation officials said. They were meant to reduce noise levels below 67 decibels, to lend some semblance of peace and quiet to residents along the interstate.

Lloyd A. Herman, assistant professor of civil engineering at Ohio University, was hired by ODOT for several studies, taking a closer look at problems to help the state improve ways to reduce traffic noise.

Herman said he found that road noise was reflecting off walls and that it was sneaking through some gaps. That led ODOT to modify barrier design and to use computer software that better predicts reflection, he said.

"It was no fault to them," Herman said of ODOT. He said the agency was following the same technology that everyone across the country was using at the time.

In recent years, ODOT also has quit building walls with gaps and changed the design of the walls to help absorb noise, said Keith Smith, an environmental engineer who oversees projects in seven counties, including Hamilton, Clermont, Warren and Butler.

Walls that have since gone up on I-71 north of Interstate 275 are textured, Smith said, as are barriers being constructed along a stretch of I-275.

"There are small gaps in the texture to make it more spongelike. It's a coarse texture, supposedly trapping sound in the texture," he said. "That's all we put up now."

E-mail smclaughlin@enquirer.com