But last week, the Alexandria government, striving to tax used cars at a rate closer to their actual value, told LaValle her Volvo was worth $1,908 -- up from its estimated value of $200 just last year. LaValle's car-tax bill correspondingly jumped from $10.40 last year to $99.22 this year.

"At first I thought it was a mistake," she said. "I thought the computer screwed up." To her dismay, she found out she was wrong.

LaValle and about 400 other owners of certain older cars and trucks in Alexandria recently received their annual personal property tax bills. Because of the new assessment method, most discovered dramatic increases in what the city says their cars are worth and the taxes they owe.

LaValle and other incensed motorists have flooded the offices of the assessor and City Council members with dozens of calls and letters.

Many say they are disturbed by a method that makes an owner of a vintage Chevy Corvette, for example, pay a disproportionately higher tax than the owner of a vintage Ford Mustang. Many see that as unfair, and some plan appeals.

"It shows a lack of intelligence," LaValle said of the reassessments. "It's typical Virginia bureaucracy at its best."

But city finance officials said the tax increases, in some cases more than 6,000 percent, are the result of the first part of a two-step process to more fairly tax the 70,000 registered vehicles in Alexandria.

The high price of many new cars has heightened not only demand for used cars but also their values, even if they are several years old, a spokesman for the National Automobile Dealers' Association said.

Although the city stands to gain $200,000 through the new taxation method, finance officials emphasized that the change was made to correct past inequities rather than to raise additional funds.

Roy Clark, Alexandria's acting finance director, said that in the past the city had no way of knowing what older cars were worth, so they were given a nominal value of $100 to $200, and were therefore undertaxed.

"A battery and four tires are worth $100," he said. "We had to comply with the state law that says we must assess personal property at its fair market value."

In determining the market value of older cars, Clark used the dealers' association guide as a reference, as the city has done in the past. The NADA book lists all car and truck makes and models and their suggested trade-in value for the last seven years.

Up to this year, Alexandria assessed 8-year-old cars at 70 percent of the value of the same model manufactured a year earlier. Cars nine years and older were assessed at no more than $200.

But this year the city singled out cars and trucks made in 1975 that are worth at least $2,000 according to the NADA guide. All 1974 cars of the same make and model were then valued at 90 percent of the 1975 cars' NADA book value.

For each model year before 1973, the values of those cars were depreciated an additional 10 percent until they fell to the $100 minimum, Deputy City Manager Bradford Hammer said.

But 1975 cars not worth at least $2,000 are still taxed under the old method. The result, to cite one example, has been that an 11-year-old Datsun sports car was not taxed the same as an 11-year-old Dodge station wagon. Last year, the city would have valued each car at no more than $200.

This year, according to the city, the sports car is worth $2,070, and its tax, computed at $5.20 for every $100 of assessed value, swelled from $10.40 to $107.64. But the old station wagon remains worth no more than $200 because its 1975 version is valued at less than $2,000 in the NADA guide.

"It's one class of automobile owner being discriminated against," said Bill Hurd Jr., whose 1962 Mercedes-Benz was reassessed at $550 from last year's $100.

"We sort of regret the feeling on the part of some people that we are being arbitrary," Hammer said. "This is a reasonable approach."

Clark said anyone with questions about the reassessments should call his office at 838-4560. Appeals based on condition of the car require a written estimate of repair costs the car needs; appeals based on age should be accompanied with a dealer's appraisal, he said.

Clark said that next year the system probably will be expanded to include all older cars, not just those 1976 models worth at least $2,000. Just how that would be accomplished is unknown.

One method under consideration is to use a newly available NADA guide that would increase the model years of cars covered from seven to about 16 years. Another approach would be to affix values to all older cars based on an analysis of the current prices of used cars in Alexandria.

Currently, Fairfax and Prince William counties conduct such surveys to assess their older cars. Arlington County relies on a system much like Alexandra's old method, something City Council member Donald C. Casey wishes the city still used exclusively.

"Considering the staff time taken by appeals and all the grief to members of the council, it is just not worth it," he said of the new system. "I much rather we had stayed with the old system."

City Manager Douglas Harman supported the new value method, however, and noted this year's selection of certain older cars for review was a "reasonable transition" toward reassessing the entire pool of Alexandria's older cars.

Meanwhile, LaValle is preparing an appeal of her car's reassessment. She has documented that her Volvo, with 129,000 miles, has not run since August, and when she recently offered it as a trade-in for a new Toyota, the car dealer wouldn't give her more than $200 for it.

The car sits in her back yard, where leaves have found their way into its musty interior through the open window.

"If they turn my appeal down," LaValle said, "they'll have to take me to court. I will not pay my tax at that rate."