By the time Sharon Mistler drives to a Metro subway parking lot, all the handicapped parking spaces frequently are filled -- by able-bodied motorists. Mistler, who uses a wheelchair and drives a specially outfitted car, circles the lots until she finally gives up and takes Interstate 66 into work.

It's the same situation at grocery stores, apartment complexes, restaurants, and the place where she works, she says. At one time Mistler underwent chemotherapy at Georgetown Hospital, and "time and time again delivery trucks, university cars {and} other cars would park {in handicapped spaces}, to the point that I couldn't be sure I'd make my treatment."

It's a familiar lament, according to advocates for the handicapped, who say regulations protecting parking spaces for the handicapped are frequently ignored both by the public and by police.

Last month, after receiving repeated complaints from people with disabilities, Fairfax County police set out to find out how bad the problem was. Normally Fairfax police ticket 60 violators in a week. During a special enforcement effort, they nabbed 699.

"It's a violation that's really silly for people to commit," said Lt. Dana Libby, an aide to the deputy chief for operations in Fairfax. "Folks feel there aren't enough parking spaces, or that they'll just run in and just run out."

One reason for the widespread illegal parking practices could be that such tickets have been rare in the past. "I'm sure that's part of it," Libby said. "It is an important violation, but when you have officers responding to calls for" serious crimes, such crime "takes precedence over just checking parking lots to see if there is a violation."

The largest numbers of tickets issued during the special effort from Sept. 8 through Sept. 16 were at shopping malls, such as Tysons Corner and Springfield Mall, in part because they have a large number of handicapped spaces, Libby said. Many tickets also were issued at multiplex theaters and Metro stations, he said.

People who use wheelchairs need the special spots, Mistler said, because they need the extra large spaces to accommodate their wheelchairs when getting in and out of their cars and because of the access to curb cuts.

Some handicapped motorists, unwilling to wait for the police, take revenge more directly.

"Sometimes I get real angry and leave notes on their windshields," said Marian Vessels, director of the Governor's Office for Handicapped Individuals in Maryland.

In one Arlington parking lot, it is not unusual for motorists illegally parked in handicapped spaces to return to their cars and find big red-and-white signs plastered across their windshields. The signs, which take up to a half hour to scrape off, say, "You are illegally parked in a handicapped space" and are quietly placed there by disgruntled people with disabilities.

Sometimes, Vessels said, she reports the violators to police, but she added, "Obviously it's not a high priority for policemen."

Montgomery County, for example, enforces the handicapped parking laws as part of an officer's regular duties, said Sgt. Joseph Price. One such ticket was given out between Monday and Friday this week, according to the county's parking division.

"A lot of {disabled} people find they can't go grocery shopping when they intended to because there are no parking spaces they could use," Vessels said. "Even if {illegal parkers} are only there for a minute, there's a limit to how many times you can circle a lot" waiting for a space.

Most jurisdictions, including Maryland, Virginia and the District, require either a license plate with the wheelchair sign on it or a portable tag that can be hung around the rearview mirror signifying that the driver or passenger in the car has a physical handicap. These tags generally are issued by motor vehicle departments after they receive certification of a person's disability.

The fine for illegally parking in a handicapped space is $50 in the District, Montgomery and Fairfax, and $100 in Arlington, officials said.

Arlington County, in response to complaints from groups representing disabled people, started a hot line for reporting illegal parking in handicapped spaces last August. But Sgt. David Green, of Arlington's special operations section, said that some handicapped people are misinformed about who is illegally parked.

For example, tickets can be given only at spaces with above-ground signs, not where signs are painted on the pavement, Green said. Additionally, although a car may not have a handicapped sign on the license plate, there may be a sticker on the dashboard or around the rearview mirror that the reporting person may not see, Green said.

"I don't think it's a problem," Green said. He said very few calls have been received through the hot line since August. "The problem is more one of perception than one of reality," Green said.

That sentiment gets some disabled people riled.

"There's been a lot of complaints and a lot of inactivity on the part of the police department," said Don Swain, an activist for disabled people in Maryland. "When you only have a county police department, they're looking for rapists, beaters and the like. You need an auxiliary team to give out tickets."

Swain suggested that private citizens be deputized to monitor handicapped parking spaces. "A lot of retired people, they'd love to get out and get some of these people and nail them," Swain said. "Some of these people have no concern at all."