The Washington State Department of Transportation has asked  the city of Seattle for a noise variance to allow nighttime construction on the State Route 520 bridge for the next seven years. About 50 residents of waterfront communities near the construction had one word for that request at a recent meeting: Shush.

During a meeting held April 6 at Saint Demetrios Hall on Boyer Avenue East, Deputy Engineer Manager Todd Harrison told residents certain elements of the SR 520 project couldn’t be done without placing workers next to live traffic lanes.

The department wants to move construction into the night in order to avoid construction during periods of peak traffic, which could mutually compromise workers’ safety — and drivers’ commute times.

But residents like Pete DeLaunay think the seven-year request is “crazy.”

“We understand that the road has to be built,” said DeLaunay, who serves as president of the Portage Bay and Roanoke Park Community Council. “Our concern is that it will be built in a way that really compromises public health, compromises our neighborhoods in many meaningful ways.”

He added, later: “The idea of cost saving, efficiency, expediency at the cost of public health is really disturbing and concerning.”

The Montlake phase of the project is scheduled to begin in 2018 and expected to take four to five years to complete. Improvements planned during this phase include a new Montlake interchange, a freeway lid that will allow construction over 520, new on-ramps and a land bridge. WSDOT has requested the variance to cover six years of construction and clean-up, plus an additional year to cover delays.

According to the noise variance application, “Completion of all construction activities during only daytime hours would be unreasonable in light of public or worker safety and would require multiple periods of closure of SR 520 and Montlake Boulevard during peak traffic periods and would result in extensive delays to the travelling public and increase traffic volumes on city streets.”

Colleen McAleer, vice president of the Laurelhurst Community Club, said she believed the department had not met the criteria for the variance.

“The application doesn’t meet any other requirement than just the general argument that it would be cheaper if they run construction all night along,” McAleer said. “And we don’t think that justifies the loudness of the decibel levels.”

To set a baseline decibel level for the application, WSDOT employees sampled current nighttime noise in the area surrounding the construction site. According to the application, all monitored locations exceeded the city of Seattle nighttime noise limits of 45 decibels.

“What we are requesting from the city is to be allowed to produce up to six decibels higher than those averages over the nighttime hours,” said Lawrence Spurgeon, the project’s environmental manager.

The six-decibel increase would result in a range of 62- to 78-decibel noise limits at night, depending on the site.

“The human ear can barely perceive a three decibel increase, while a five decibel increase is about one and one-half times as loud,” according to the application.

Transportation officials said work would not occur every night and some phases of the work would generate less noise. An independent noise monitor would be hired, and a 24-hour live telephone construction hotline will be maintained for the duration of the project.

Without a variance, construction is allowed between 7 a.m. and 10 p.m. during the week and 9 a.m. to 10 p.m. during the weekend and holidays. During this time, the city allows construction activity to exceed the noise level limits by 25 decibels. Noise level limits vary depending on land use of sites.

Some residents said they were concerned higher noise levels would harm their children’s health.

McAleer pointed to noise standards established by the World Health Organization, which, according to the agency’s website, recommend an average noise level of less than 40 decibels outside of bedrooms. WHO officials write that louder ambient noise levels can lead to adverse health effects associated with disturbed sleep, such as hypertension, depression, and likelihood of accidents.

The Laurelhurst community has dealt with construction noise for the past three years, McAleer said.

“Our experience tells us this noise variance request is too long and too loud,” McAleer said.

The public comment period for the noise variance for the Montlake Phase has been extended to April 28. Comments can be sent to prc@seattle.gov.