Surprising as it may seem, Virginia highway officials can't tell us how many commuters are using the new toll road alongside the Dulles Airport freeway.

Lynda South, speaking for the state Department of Highways and Transportation, told my colleague Barbara Carton that traffic counters won't be installed until later this week.

While about $8,000 in tolls was collected during the first 24-hour period and about double that the second, they vary so much from day to day and from one toll booth to another that it was impossible to extrapolate the totals.

Before the road opened little more than a week ago, officials estimated that 40,000 vehicles would use the road daily, a figure rising to 60,000 by 1995. Metro Scene's guess is that those figures are conservative.

The only real trouble spot on the new tollway, South said, are mile-long backups of eastbound travelers in the morning who want to exit at Rte. 7, the Leesburg Pike. For 25 cents more, they can avoid the jam by exiting at the next interchange, Spring Hill Road.

Some commuters still try to fight the tolls by illegally using the Dulles freeway itself. Federal Aviation Administration police have issued citations, costing $25 each, to at least 100 such freebie seekers. "They're from the Reston area, from Herndon -- you name it," police Lt. William B. Morse said.