A Vienna neighborhood that is hearing just how much traffic travels along the Dulles Toll Road each day received notification it did not qualify for the Dulles Toll Road Highway Noise Program, falling 3 decibels short of the necessary level to qualify.
Representatives from the Metropolitan Washington Airports Authority, which became responsible for the toll road in 2008, spoke with the residents of Shouse Village at the homeowners association's regular meeting Sept. 18.
"The purpose of this meeting is to be as transparent as possible regarding the Airports Authority's findings," said Michael Cooper, MWAA's manager of state and local government affairs. "... The Airport Authority understands that your community is experiencing traffice noise levels coming from the Dulles Toll Road. Tonight's presentation is designed to equip your community with the information you requested about our process, our policy and findings from the Traffic Highway Noise study so you can be better informed."
The meeting attracted dozens of Shouse Village residents, all of whom supported the assertion their neighborhood should qualify for a sound wall to protect from the toll road's noise.
Neighborhoods surrounding Shouse Village all have existing sound walls and qualified for either wall repairs or replacements based on the latest noise test results.
MWAA began development of a noise policy for the toll roll in early 2010 after assuming responsibility for the Dulles Toll Road in late 2008. After public meetings and input from the Federal High Administration and the Virginia Department of Transportation, the MWAA Board of Directors adopted a Noise Policy in February 2012.
The policy established three criteria an area must meet before qualifying for a sound wall: toll road impact, feasibility and reasonableness. Results from a noise test indicated Shouse Village did not meet the minimum impact level necessary for a sound wall.
To qualify for a sound wall, an area must experience noise equal to or greater than an average of 66 decibels during the loudest hour worst-case scenario, as determined by the highway noise computer model. The worst-case scenario included expected decibel levels the community would hear when Dulles Rail is completed.
The computer model showed Shouse Village hits 63 decibels under those circumstances.
In Shouse Village, the noise measurement testing consisted of a 20-minute monitoring session at two locations along Sibelius Drive — one between 9:20 and 9:40 a.m. Aug. 31, 2010, the other between 10:45 and 11:05 a.m. the same day.
The results are used to calibrate the model that determines the worst-case scenario noise level, not to determine whether the area qualifies for the Noise Wall Program.
But residents questioned the validity of the test results, doubting engineers from MWAA and JMT Engineering could get an accurate outcome from the model when measurements were taken in off-peak hours at the end of the summer.
"There are very strange acoustics in Shouse. There are places you can go where the sound is dead, you can't hear anything. Then you walk 10 feet and you hear everything from Wolf Trap or the toll road," one resident said. "You have to be very careful whether you're measuring dead space or live space, and at what time of day."
The engineers said topography is accounted for in the study.
To reassure the residents of the validity of the results, MWAA offered to retest the area, using residents' suggestions for where and when the measurements should be taken. Shouse Village accepted the offer.
A date has not yet been set for the retest. A decision will likely be made in early October, and a retest will likely take place sometime in December — a time of year residents agreed would come closest to mimicking the worst-case scenario because traffic flow is heavy and leaves are not on trees to block sound.
"I think what we're hearing from the audience is 62 decibels is unpleasant," said one resident, who asked both MWAA and a representative from U.S. Rep. Frank Wolf's (R-10th District) office whether another option exists to help Shouse Village block the noise.
MWAA said it is looking into what the next step would be for community's like Shouse Village that do not qualify for sound walls. Craig Witham, a legislative assistant to Wolf, said the congressman is committed to helping neighbors affected by the noise from Dulles Toll Road.
"Mr. Wolf's position has always been that communities that are impacted noise should get a sound wall. So I think you're hearing that MWAA has put out a model and they're willing to work with the community to try to get a successful resolution," Witham said. "So Mr. Wolf supports getting a sound wall for communities that are impacted. He will do what he is able to do to make that happen."
A few residents suggested expanding the testing area to include their homes that lie just outside the boundaries MWAA set, but one resident suggested tightening the boundary would yield results beneficial to the neighborhood because a sound wall must have better potential to reduce noise levels by 5 decibels for at least 50 percent of the affected properties.
"I would hate to see Murphy's Law happen where you [MWAA] come back out and say, 'Congratulations, you meet the 66 decibel threshold, however, it's not feasible because a sound wall will not improve the sound levels at more than 50 percent of the affected properties,'" the resident said.
The estimated cost to test at 81 different sites along the Dulles Corridor was about $120,000, said Kimberly Gibbs, an MWAA spokesperson. The cost to redo the noise measurement testing in Shouse Village has not yet been determined. Costs associated with the Noise Wall Program are funded by the Dulles Corridor Enterprise Capital Improvement Program, which is derived from toll road revenues, Gibbs said.
MWAA said it would provide guidelines to help Shouse Village residents make decisions regarding the retest ahead of the homeowners association's next monthly meeting scheduled for Oct. 16, when the residents would discuss when and where the retests would take place.