The last time nursing assistant Terrie Patterson saw her car was three months ago. Ever since then she has had to ask friends for rides to her midnight shift job.

Patterson's 1986 Chevrolet Sprint is not missing. It is sitting in a D.C. police department impoundment lot where it was taken in March after a friend who borrowed it was arrested on drug charges.

Patterson was not present during the arrest, but police confiscated her car using a city law that allows the seizure of property and cash during drug arrests.

The law bars the city from gaining permanent possession of cars when an owner is unaware the car is being used for a drug transaction, but police and lawyers say that police are now routinely seizing most cars and money and are leaving final determination about ownership to the courts. The process to return the property could take up to two years.

"It's a scandal," said Arthur Spitzer, legal director for the ACLU, that "certainly does not comport with any modern conception of due process, especially in cases where people who are not convicted or even charged with any crime lose their property."

Police officials reject criticism of the law and say its enforcement has been highly successful in sending a stern warning to drug users. Since District police announced plans last September to enforce the law as part of the city's massive crackdown on street drug trafficking, police have seized more than 300 cars and nearly $1 million in cash, a figure more than double the seizures in the previous period last year.

No official figures exist on the number of people whose cars or cash have been seized even if they are not suspected of wrongdoing since Operation Clean Sweep began last summer. However, several defense lawyers said they are filing challenges in more and more of these kinds of cases.

In addition, these lawyers said, city attorneys are refusing to return property in cases where charges are dropped by the U.S. attorney's office or no drugs but large amounts of cash are found. In recent weeks, some Superior Court judges have agreed with the challenges and ordered the return of some cars.

"It's the other side of Clean Sweep," said lawyer Brenda Granttland, who represents Patterson and about 10 other clients in similar circumstances. "If you throw out a wide enough net you are going to pick up some innocent people."

Capt. William White III, a police spokesman, pointed out that for every 56 arrests during Operation Clean Sweep only one car has been confiscated. "Those figures don't reflect abuse," he said.

But to others such as Patterson and Spitzer, the law represents a rigidly applied standard that has victimized innocent people or punished others far too severely.

"Is it against the law to loan out your car?" asked Patterson, a single mother of two who said she lent her car to a friend in exchange for his making a few minor repairs. Patterson is still making her $355 in monthly car and insurance payments.

Confiscating property during drug arrests is nothing new. Enforcement authorities in heavy drug traffic areas such as Miami have been using a 17-year-old federal statute for years to seize boats and airplanes used to transport large shipments of narcotics. Recently, however, other jurisdictions such as New York City and the District, which modeled its law after the federal one, are turning to these kinds of statutes to attack small-time drug users.

Under the current city law, vehicles can be confiscated only if they are "used . . . to transport . . . for the purpose of sale or receipt" an illicit narcotic with the knowledge of the vehicle's owner. Police spokesman White, however, said it is the department's policy to turn over most cars or money to the Office of the Corporation Counsel, the city's attorney, for a decision about forfeiture.

Once there, a spokesman said, civil forfeiture actions are filed against more than 90 percent of the confiscated items.

"Our posture is that even though the owner of the vehicle may not be the person arrested or may not be in the car," said White, " . . . one of the factors to be considered is whether the owner had knowledge of what the person who had borrowed the car was using the car for."

White and a spokesman for the corporation counsel's office said also that the city routinely proceeds against people who may be charged with possession of a drug rather than selling it or against whom criminal charges may have been dropped altogether because the standard of proof is far easier to meet in a civil case. In civil cases, the government is required only to show a "preponderance of evidence" rather than meet the far stiffer criminal standard of "proof beyond a reasonable doubt."

Although similar arguments about the government's right to keep such property have been upheld by the Supreme Court, they have met with varying degrees of success in Superior Court. Judge Harriet Taylor in December ordered the city to return a car belonging to a woman convicted of drug possession, but in February Judge Curtis von Kann rejected a defense motion that the city was not entitled to proceed because the defendant pleaded guilty to possession of PCP.

Lawyers in the corporation counsel's office said they sympathize with otherwise uninvolved people whose cars have been seized, and give car cases a high priority, but they explained that the city often cannot determine if an owner is innocent until a lengthy investigation is completed. They said a plan to use administrative hearings, such as those in New York City, is being considered and would eliminate the need to go to court.

In the District, forfeiture cases can take 2 1/2 years to get to trial in Superior Court and become so expensive to try that most lawyers will not accept these cases. Owners, too, get worn down by documentation requests that usually include a demand for income tax returns for the past five years.

"I don't think anybody would want to be questioned about all their financial transactions," said lawyer Paul Zuckerberg. He said one of his clients recently decided to accept as a settlement $1,000 of $8,000 confiscated by police from his car during a Clean Sweep roadblock because he did not want to go through the expense or trouble of a trial.

It took Sandra Harris, a nurse in Maryland, 2 1/2 years to secure the return of her 1981 Datsun that was confiscated when her son was arrested in October 1985 on drug charges. Her son's name was on the title of the car, but Harris sought the return of the car on the grounds that she and her son had bought the car and she had made nearly all the payments on the car for the six months before her son's arrest.

Superior Court Judge A. Franklin Burgess Jr. agreed and ordered the car returned to her March 1. But even then Harris did not regain her car until May 22 because of administrative problems. Shortly before that date, the city sent Harris a letter requesting storage fees for keeping her car past March 1, a request that was later rescinded.