Apple Valley's Cedar Avenue has the odd distinction of having one of the state's shortest noise walls.

Despite city and county opposition, the 376-foot-long wall was built this summer because of strings attached to federal funding. Such funds come with noise rules that give residents a voice in deciding whether they want a 20-foot-high wall looming over their homes.

In Apple Valley, the desires of six homeowners were enough to require construction of the $124,000 wall.

In times of tight budgets, rules that require such walls, even when local officials aren't sold on their usefulness, are getting more scrutiny. The noise wall rules were revised this summer, but residents still have the last say -- only now, renters get a vote instead of just homeowners.

"I can't believe a small number of families have this kind of sway over a project," said Apple Valley City Council Member John Goodwin. "We on the council thought it was absurd. It is only a block long; the sound comes in either end. ... I think it is a ridiculous waste of money."

Even some residents living behind the wall, just south of 153rd Street, are questioning it.

"It still seems loud to me," said Natasha Kennedy. She moved into her townhouse unit in June while the wall was going up. "I am not impressed."

Her neighbor, Steve Short, who voted for the wall, is having second thoughts.

"It does help," said Short, a longtime townhouse owner who misses seeing the sunrise. But "for the amount of noise it takes care of, it wasn't worth putting in. ... You can hear it [traffic noise], but it is not as predominant."

Federal grants paid $23.4 million toward the nearly $56 million project, now underway, to turn Cedar Avenue into a corridor for bus rapid transit, designed to mimic light rail but with buses instead of trains.

Noise analysis indicated the wall would do some good, though city and county elected officials were skeptical, said County Engineer Mark Krebsbach, who oversaw the project.

At local officials' request, U.S. Rep John Kline, R-Minn., contacted federal highway officials in support of their efforts to stop the noise walls. His spokesman, Troy Young, said Kline was pleased the agency agreed to nix one of two proposed walls. Federal officials said they dropped it because costs rose too high and one resident switched her vote and thus the majority sentiment was anti-wall.

However, Young added, "the process of federal funding for transportation is still onerous and the congressman supports cutting through the bureaucratic red tape by giving states and local communities more flexibility with how they can use federal dollars."

State and federal rules require road project planners to model future noise levels and the effect on nearby residents.

Residents don't always get to vote: Nearby residents get a say if the potential wall first meets cost-benefit and noise-reduction standards. The rules say if noise analysis shows sound barriers could reduce noise to nearby residents by 5 decibels (a 10-decibel reduction would cut noise in half) and cost less than $43,500 per benefitted home, then residents can vote.

It will be easier to trigger a vote on a wall now than in the past because the cost threshold was raised in June from $32,500 to $43,500, the first such increase since 1997.

The new rules do strengthen the noise-reduction standard a bit: They require a proposed wall to reduce noise for at least one home by 7 decibels, said Peter Wasko, a noise specialist for the state Department of Transportation.

On Cedar Avenue, one potential wall segment in Lakeville was dropped early because it didn't meet cost/benefit and noise-reduction criteria. But two groups of Cedar Avenue residents were asked to vote on possible walls in 2009. One group, north of 160th Street, voted 4-3 for a 720-foot-long wall. But then came the one resident who switched her vote and the outcome to anti-wall, said Kristine Elwood, project manager for the county.

The other group of 11 homes, with five homeowners not responding, voted 6-0 for the wall that went up this summer. The wall, tan painted planks bolted to concrete posts, protects two townhouse buildings.

While Minnesota has at least one shorter wall -- a 150-footer in Eden Prairie -- shorter walls are not unusual in the nation, said Doug Hecox, a Federal Highway Administration spokesman. He said walls are designed to preserve quality of life for residents living behind them. "Throughout the nation, there are some [noise walls] that are thousands of feet [and miles] long while there are others which are less than 20 feet long," he said. For example, federal records show Florida has about two dozen noise walls shorter than Apple Valley's block-long wall.

Hennepin County built the Eden Prairie wall in 2009 on Pioneer Trail, said County Engineer Jim Grube. He said it protected three homes from heightened noise after a road upgrade.

Grube said he was surprised noise modeling showed the little wall met minimum noise reduction standards. "One hundred fifty feet is getting awfully short," he said.

Jim Adams • 952-746-3283