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The 1996 Measure B project of noise reduction on Highway 85 might have been placed on hold, but its test run has not.
A micro-grinding test run for noise mitigation began Oct. 30 and will run all nights except Sundays through Nov. 17 along the northbound route of 85 between Saratoga Avenue and Saratoga-Sunnyvale Road.
Although the project has been shelved until further notice, the Santa Clara Valley Transportation Authority (VTA) decided to continue the test run. "Regardless of money, we have to find out if the method works," said John Pilger, public information manager for VTA. "There will be no point in grinding if there is no noticeable difference."
Pilger points to the fact that the human ear only responds to a change of three decibels or greater—anything less and the ear cannot tell a difference.
"We want to make sure that this change would create a perceivable difference," Pilger said.
Micro-grinding is currently the only approved method for noise reduction. Parallel saw-wheels are used to grind down roadway tinning, creating a smooth surface that is quieter than the standard diamond-ground pavement.
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Photograph by George Sakkestad
The Santa Clara Valley Transportation Authority has begun a test run of micro-grinding along Highway 85. Micro-grinding is a new type of pavement grinding that uses a parallel saw to scour down rough patches of road.
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A month prior to the first test run, the VTA took sound readings adjacent to the road and in surrounding neighborhoods. Thirty days after the current test is completed, new sound measurements—involving volume and pitch—will be taken to see what changes, if any, have occurred. Pilger said it is likely that report findings will be available in early January.
Test runs will involve monitoring regular traffic, as well as using test vehicles. Pilger said test vehicles would be used in order to ensure at least one set of consistent measurements and to better identify what types of cars and tires cause what kinds of sounds.
The project, slated for completion in fall of 2004, was recently placed on hold due to lackluster sales tax revenues. Roughly 20 transportation projects, including the $9.3 million noise mitigation project, were reliant on sales tax revenues that have not met projected standards. Funds are now only being budgeted for top-priority endeavors that affect the entire county, such as easing traffic congestion and streamlining highway interchanges.
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Photograph by George Sakkestad