But the Santa Clara Valley Transportation Authority (VTA), conducting the study and eventually mitigating the entire stretch of highway from Interstate 280 to Highway 87, says Caltrans, which owns the road, won't let VTA pave it over with open-graded asphalt.

Instead, Caltrans wants VTA to keep the existing concrete, expected to last decades longer than the asphalt, and just grind down the longitudinal tining on the roadway that, when driven over, creates a high-pitched hum that has irritated neighbors since the highway opened in October, 1994. A process of microgrinding, it says, should bring about the same amount of noise reduction—between five and seven decibels—that the asphalt would.

VTA wants to see for itself. So it plans to try the technique, said to produce better results than regular diamond grinding, and see if the claims are true on a one-mile stretch of Highway 85 from Calabasas Creek south into Saratoga to Azule and Kevin Moran parks.

Microgrinding uses parallel saw-wheels to remove bumps and roughness, leaving a smooth surface with narrow, longitudinal grooves that keep the roadway skid resistant. The one-mile test segment was chosen because it provides a good, level testing surface.

VTA will take noise measurements both near the tire-on-road surface and in the surrounding neighborhoods before starting the test early next month and after completing the two to three weeks of grinding. The grinding will occur between 11 p.m. and 6 a.m., to minimize the impact on traffic, and will involve one-, two- and occasional all-lane closures.

Once it has the results, by the end of September, it will either see that the grinding will work and commence doing the rest of the roadway early next year. Or, if they show a less successful reduction, VTA will try "one more time" to convince Caltrans to let it lay the asphalt, said Mike Evanhoe, VTA director of highway programs.

In a presentation to affected neighbors at the Saratoga Civic Center July 18, Evanhoe and Jeff Funk, VTA highway programs manager, explained this to the about 50 people in attendance. But most of those wanted to know, not only why it was taking so long to rid the roadway of noise, but why VTA couldn't just do what they want—pour the asphalt.

Saratoga Mayor Nick Streit explained to them that the city has worked with VTA, and even engaged state officials, in trying to get what the neighbors want, to no avail. Several attendees suggested writing more letters to public officials.

Evanhoe pointed out that, although asphalt is more proven to reduce noise than grinding, which hasn't been tested, its noise reduction features diminish over time, long before the surface itself needs to be replaced. In five to seven years, when the asphalt wouldn't reduce noise anymore, Santa Clara County won't have any more money from its Measure B transportation tax—$9 million of which is to fund the Highway 85 mitigation project—to lay more asphalt, he said. The money is sufficient to allow VTA to mitigate the roadway, using either process, only one time, he said, and depends on the neighbors' willingness to go along with their only real option right now.

"We have offered to do the test to see if we can get a long-term solution that will last the life of the pavement. We need the data to be able to say, 'Yes, it works,' or 'No, it doesn't,' " Evanhoe said. "If we get the seven [decibels] and you still say you don't want grinding, I suspect the money will go to some other program."

The neighbors also weren't happy about the nighttime noise or the airborne dust that the test process would cause. But one neighbor said that it might be necessary to put up with it in order to get what they really want.