The annual Fairfax County personal property tax on a $10,000 Toyota is $457 and $1,828 on a $40,000 BMW. But the fine for driving without the bright blue and red decal showing you've paid is only $25.

Faced with numbers like these, tens of thousands of Fairfax residents have chosen to risk the $25 ticket rather than pay the tax to get the decals.

On Jan. 11, police began setting up checkpoints outside developments where residents had complained that vehicles without stickers were endemic, and in the next four weeks issued 1,119 tickets. On Jan. 14, the County Finance Department also sent 40,000 letters to Fairfax car owners who collectively owed an estimated $6 million in unpaid taxes.

"They would rather pay a $25 fine for not having a sticker than pay $300 or $1,000 depending on the value of their car," said Supervisor Martha V. Pennino (D-Centreville). "They're even willing to pay three or four or five fines."

Pennino said one of her constituents had called to complain that on his small cul-de-sac, 18 cars had no stickers. "Now when someone calls me to say they've got 18 cars, that indicates they've got some sort of a problem. They're using Virginia roads and they should pay their fair share," she said.

Pennino has proposed raising the fine to $100, with $75 refundable if the offender then pays his tax.

Police spokesman Warren Carmichael says police continue to catch about 300 people a week driving without decals. "There are repeat offenders," he said. "We do know there are people have indicated they would take their chances rather than pay their taxes."

Stickerless cars annoy other drivers who have paid their taxes, he said. "People take umbrage at seeing other people without them," he said. People living in rental developments appear slightly less likely to get decals than those living in areas where most residents own their homes, he said.

The county collected $113,060,307 in personal property taxes in fiscal 1987 from taxes on 635,000 vehicles in the county, according to Supervisor of Assessments Paul Smith. It also collected $10,413,425 in license fees, the additional payment of $20 or $25 that car owners must pay for their windshield decals along with their taxes.

Smith said his office compared Virginia Department of Motor Vehicles records with Assessment Office figures earlier this year and found 40,000 cars were registered in the county but not declared with the county. While many of these cars may have been junked without notifying the agency, he said, other people may owe taxes on cars housed in Fairfax but registered in another state.

Decal renewal forms are due May 2.