ASHLAND, Ore. -- Since infrared cameras went up, Oregon highway workers at Ashland have nailed about a trucker a day cheating on the requirement to stop at a weigh station.

The $8,000 camera system at the Ashland port of entry is the state's first, but state Department of Transportation officials say truckers should expect them at other weigh stations.

Since the cameras went up March 13 in Ashland, officers have already issued more than 30 citations, almost as many as the six months before, said Sven Johnson, who manages the Ashland station.

"It's a little bit more than I expected," he said. "Now we're hoping that we're going to all but eliminate the problem."

Oregon law requires truck drivers to check in for inspections and have their weight and mileage logged, which determines the amount of tax they must pay to drive through the state.

In 2004, officers stopped pulling over trucks and began using digital point-and-shoot cameras to nab offenders. The pictures, however, were not always clear, especially at night. Johnson said that is where infrared comes in.

One of the infrared cameras is aimed at the side of trucks, the other records license plate numbers as they pass the state's port-of-entry weigh station across the highway from Ashland.

Truckers who bypass the weigh stations receive a photo in the mail and a $427 fine. A repeat violation could result in a $2,500 ticket, a 90-day suspension or jail time.

Cheaters often have suspended licenses or are driving without an Oregon permit, cheating the state of tax dollars and increasing hazards, Johnson said.

"Overweight trucks have a negative impact on the roads," he said. "If you're running overweight, you're going to tear up the road."

Some drivers with good records can legally bypass the station under the Green Light system, which allows trucks equipped with the technology to drive over scales imbedded in the road and gain clearance automatically.