The bitter snows of last winter have chalked up another victim: $37,500 worth of reflective devices that Virginia highway authorities implanted along traffic lanes on Shirley Highway.
The markers, round plastic disks known as cat's eyes, were imbedded as part of a statewide experiment to improve highway lane visiblity along a two-mile stretch near the Pentagon. But of the 5,000 glued to the Shirley Highway pavement a year ago, only 1,000 remain.
"I think the culprit was the susceptibility of the raised markers to snowplows," said Al Coates of the Department of Highways and Transportation.
Highway officials are now looking at an improved - and costlier - cat's eye that would be imbedded in grooves cut into the pavement. According to Neal Robertson of the highway department's research branch, the new version should be impervious to snowplows. The improved markers cost $15 to $20 each. The first batch had a unit cost of about $7.
State officials knew the markers would not withstand snowplows when they decided in 1977 to apply them to Shirley Highway, the state's busiest road, said David Gehr, the state's regional transportation engineer. But they went ahead anyway in order to see if the cat's eyes eased visibility problems on rainy nights or on bright days when light reflecting off white cement bridges and lane dividers tended to dazzle motorists.
There are no data yet on whether the markers have helped. "But we are measuring visibility on roadways in bad weather with and without markers," said Robertson.
Researchers have found that on a bad night with poor visibility, painted road lines could be seen 200-250 feet ahead, while lines with raised plastic cat's eyes could be seen up to 800 feet.
While some Northern Virginia commuters say they have found the cat's eyes helpful, one congressional aide, originally from snowy Chicago, was not surprised that the cat's eyes fell victim to the snowplows.
"I know they never put those things in any place where they use snowplows," said Suzanne Langsdorf, 32, of Fairlington. "When I saw them put them down, I thought, what fools these Virginia highway people are."
The supposedly foolproof reflectors now being eyed by highway officials have a ribbed steel casing with two prongs that slip into glue-filled shots cut into the highway's surface. The reflector portion is recessed inside the ribbed steel whichwhic , researchers say, forces any maurauding snowplows to ride up and over the markers.