Photos by Eric Brady | The Roanoke Times

Virginia State Police Trooper Andy Cochran gives a reckless-driving ticket to a driver who was clocked going 82 mph in a 60 mph zone on Interstate 81 in Roanoke County.

Virginia State Police Trooper Andy Cochran approaches a driver who was driving erratically on Interstate 81 in Roanoke County. Statistics show that about 84 percent of drivers stay within 10 mph of the speed limit.

Trooper Andy Cochran jots down notes to use in court after issuing a reckless driving citation on Interstate 81 in Roanoke County.

DALEVILLE -- Vaskin Kissoyan, who lives near Washington, D.C., pulled into the Daleville truck stop Thursday to stretch his legs on a road trip to Chattanooga, Tenn., for the holiday weekend.

Interstate 81 traffic whooshed by in the background as he and his family got out of their van and contemplated where to eat.

He said he had been driving about 70 mph on the interstate and would like to see a third lane added because there are so many trucks.

"Most folks are going faster than us," he said.

Kissoyan is not the first to notice that speeding is common on I-81. The fact is that most drivers are exceeding the limit, although remain close enough to it to avoid a ticket.

You might think that with gas being up 93 cents a gallon from a year ago to $3.48 in the Roanoke Valley, motorists would have slowed down to conserve fuel, especially for long-haul trips.

Not so. The average speed of traffic is about the same on Interstate 81 between Christiansburg and Buchanan as it was a year ago -- a hair more than 65 mph, according to northbound pavement sensors maintained by the Virginia Department of Transportation.

But speedsters -- those going more than 10 mph over the limit -- make up approximately 15 percent of the motoring public using this Western Virginia stretch of I-81 known for hills and valleys.

A Roanoke Times analysis of VDOT pavement-sensor data shows a tiny drop in speeding this year compared with a year ago.

In one week in early August, the share going more than 10 mph over the limit was 14.7 percent, compared with 15.3 percent during a comparable period a year ago.

Sgt. Rob Carpentieri of the 14-county Salem division of Virginia State Police said the data reflects well on the agency's enforcement efforts, especially considering that a certain share of the high-velocity vehicles detected by VDOT were likely to have been ambulances, police cars, fire trucks and other emergency vehicles.

Take them out of the equation, and the share of speedsters is smaller.

"It sounds like the troopers are out there doing their job and doing it well," Carpentieri said.

He said the agency's enforcement strategy is to stop aggressive drivers because they are a safety threat.

This weekend, when AAA reports more than 800,000 Virginians and 34 million Americans are expected to travel more than 50 miles from home, state police will dedicate at least 75 percent of their personnel to speed control. Unmarked vehicles and airplane-assisted enforcement are other strategies used.

Carpentieri declined to say how many miles over the speed limit police officers choose to let drivers go before issuing them a warning, summons or arrest.

"We give a little tolerance in case people's speedometers are off," he said.

What share of the speeders are getting stopped? Nobody in law enforcement seems to know.

Without knowing how many speeders there are, "it's kind of like quantifying, 'How many fatalities did we prevent?' " said Corinne Geller, a state police spokeswoman.

Joel Branscom, the commonwealth's attorney for Botetourt County, which I-81 cuts through for nearly 30 miles, said local courts process a steady stream of speeding cases in an ongoing attempt to improve the safety of the highway.

Speeders face a fine and a statistical black mark for their infraction. Those whose speed is so excessive it amounts to reckless driving -- essentially 20 mph over the limit -- face up to a year in jail and a $2,500 fine.

Judge Louis Campbell, who hears many of the cases in Botetourt County, has a practice of jailing any driver who is found guilty of exceeding 90 mph, which Branscom said is fairly common. The confinement period is one day for every mile of speed over that benchmark, Branscom said.

In spite of such sanctions, speeding continues, Branscom said.

Branscom said troopers have told him: "Why write somebody for going 80? If you wait five minutes, you'll get one going 100. The thing about it is, it's not hard to catch people. It's just we are completely outnumbered."

Joanne Cooke of Covington said she knows what to do when she deems conditions on I-81 too unsafe, which is much of the time.

"I take the back roads," she said, such as U.S. 60 to Richmond.