Everyone knows each other on Malibu Drive at Edina's western edge. It's a great place to live, people say, with good neighbors and beautiful surroundings, including a wetland with pheasants, fox and deer.

But it's hard to sleep with windows open on a summer night, or even to eat dinner in the back yard. Motorcycles gun their engines. Ambulances scream. Downshifting semitrailer trucks grind their gears.

The noise comes from the Hwy. 169 bridge on the other side of the wetland. Last summer, 19 Malibu residents petitioned Edina to add a sound barrier to the bridge. They knew they would be assessed for the cost.

This week, the Edina City Council was told a barrier of preserved wood can't be built because of Minnesota Department of Transportation concerns that leaching chemicals could pollute the wetland. Any wall must be Plexiglas.

The estimated cost: $2.75 million, with possible assessments ranging from $165,000 for those closest to the highway to a low of about $21,200 -- 80 percent higher than a wood wall.

That "is not economically feasible," City Engineer Wayne Houle told the council.

And Catherine Antil, a longtime Malibu resident, agrees. "That's a bit out of reach for me," she said.

So there will be no wall. A disappointed Donna Thoele, who started the petition drive 14 months ago, said the ruling that a wall had to be Plexiglas seemed "silly."

"Can't they seal the wood or something?" she asked.

How irritating the bridge noise is varies by location. Gloria Cooper, who has lived on Malibu for more than 20 years, said she is now used to it.

"It's pretty much background noise for me," she said. She signed the petition partly because she thinks a sound barrier would help if she and her husband ever wanted to sell their house, she said.

But Antil thinks the noise is getting worse. While she said the neighborhood is wonderful -- she watches for the same big buck to visit the wetland each year, looking for a mate -- "it really is noisy out there, and I think the pollution is bad, too. You can smell it."

Carol-Jean Meldahl has rented half of Antil's twin home for four years. She said traffic passing over the low bridge makes it reverberate "like pounding on a drum." It has gotten worse since the Interstate 35W bridge collapse, she said. The noise got so bad last summer that she moved her patio set from a screened-in room in the back yard to the front yard.

"Now we're looking over our driveway, which is not like looking over a beautiful wetland and the wildlife," she said. "The noise is so intense you can't have a conversation back there."

Meldahl and Thoele wonder why the city doesn't help pay for a sound wall.

Houle said that where barriers don't qualify for state funding, the city's policy is to bill residents who benefit from a wall for its construction. That's what happened several years ago when a wood barrier was erected along Hwy. 100 near Minnehaha Creek. Houle said homeowners were assessed between $18,000 and $20,000 apiece.

"They saw it as worth it," he said.

Even wood plank and concrete post barriers cost about $2 million per mile, MnDOT public affairs coordinator Beth Petrowske said in an e-mail response to questions. She said the Edina location doesn't meet MnDOT's cost-benefit standards for a wall, and that a wall wouldn't do much good because homes are some distance from the bridge.

MnDOT reviews of treated wood walls indicate that they shouldn't be used within 100 feet of surface water because of chemical leaching, Petrowske said. Engineers also were concerned about having any barrier on the Hwy. 169 bridge because of concerns about snow storage and whether the bridge could support a barrier.

No Plexiglas sound barriers exist on state roads yet, but one will be built on the Minnehaha Creek/I-35W bridge as part of Crosstown reconstruction, Petrowske said. She said MnDOT experts haven't found another lightweight material such as Plexiglas that has a crash approval rating and is suitable for bridge barriers.

Edina will investigate low-tech alternatives to a sound wall. At the City Council meeting, council members wondered if a berm or evergreen plantings could be used to muffle bridge sound.

Thoele was skeptical, saying they'd have to be pretty big evergreens to block bridge noise. Cooper agreed, but said she hopes someone finds a solution.

"With all the smart people, the technically bright people out there, you'd think they could come up with something else," she said.

Mary Jane Smetanka • 612-673-7380