After a year-long crackdown on illegal parkers, Washington's tough parking enforcement program has decongested city streets and revived the almost forgotten practice of putting money in parking meters.

But the program has generated only half the revenue that city officials had predicted it would. It also is plagued by an archaic computer system that continues to pursue motorists after they have paid up.

"That aggressive parking program has struck fear in the hearts of the people," said Officer Winfred Harris, one of two police department traffic analysts.

"Georgetown used to be a mess, with vehicles double-parked and everything. Now it's wide open . . . Not only can you drive through now, but you can even find a meter on the street," Harris said.

But city transportation director Douglas Schneider told a City Council committee Friday that while he was "pleased with what's happened on the streets, the revenues are less than anticipated."

The program failed to generate the $12 million in new revenue that Schneider's department had forecast when the program was started last Oct. 23.

Instead the city cleared only $6 million after it spent $5 million for new equipment and 200 people hired to operate the program, according to John Brophy, head of the parking bureau.

Brophy said total revenues fell short because of overly optimstic estimates of the number of cars that would be towed and ticketed and a three-month delay in starting the program's "booting" phase.

To make matters worse, the police un expectedly wrote one-third fewer tickets this year than last for a number of reasons, including their feeling that the new parking program would pick up the slack.

But the parking bureau's outdated computer system also contributed to the problem.

The bureau had planned to hire a private collection agency last January to dun out-of-town scofflaws for about $2 million in overdue fines. But the burea held off because it wanted to avoid harrassing people who had already paid. When the city rechecked its list of 700,000 unpaid tickets, it found that 17,000 had been paid without the computer canceling them.

In addition, because of a programming error, about 20,000 District motorists avoided paying about $1 million in overdue tickets last March when they received their new license plates. The computer was supposed to identify them, but failed to do so.

Not only is the computer costing the city money, it is also causing three to four drivers to be towed or booted by mistake each week because of delays in getting information into the electronic system, Brophy said.

But a reporter recently saw three such mistakes in a six hour period at the parking bureau's headquarters.

John Parker, a computer repairman, went to the headquarters that day because his car had been booted, although he had paid all his delinquent tickes the week before. He and his boss spent two hours trying to resolve the mistake, and while he didn't have to pay, he said he didn't get an apology either.

Earlier that day, a downtown lawyer faced a similar mistake. His car was towed away because 10 tickets issued against it, which had been dismissed, still showed up as unpaid by the computer.

"We're still working with a Rube Goldberg system," Brophy said of the computer that he inherited from the city's court system, which used to process ticket payments.

The mistakes occur because there is a delay from the time a ticket is paid until that information gets into the computer system. Brophy said it usually takes about two weeks; Harry Gray, chief of the computer system, said the delay is only one of two days.

However, clerks at the program's Indiana Avenue headquarters told motorists yesterday that the program was eight weeks behind in putting information into the computer.

To reduce the number of errors caused because "none of the information (in the computer) is current," Brophy said, most booting crews now call in before they attach the orange metal clamp to the car of a suspected scofflaw.

Then a clerk manually checks all current payments to make sure that the fines have not been paid since the "boot lists" were prepared. The lists are issued every two weeks, according to Brophy.

But "with all the headaches we go through with the manual system, sometimes we still boot people twice," Brophy said. He added, however, that the number has been "substantially reduced" since the program started.

Brophy promises a new era starting Oct. 22. Then the city will put into effect a new computer system that will update payments every 24 hours.

We're going from an awful system to the most sophisticated system in the nation," he said.

The city launched its stiff enforcement program last October when 50 uniformed civilian ticket writers took to the streets.

In their first year, they issued 851,428 tickets and put downtown motorists on guard for their white caps. City police officers also kept writing tickets -- 840,278 to be exact. But this was much less than the 1.3 million tickets they wrote the year before.

The parking program booted just as many cars this year as the police did last -- 11,000, and police booted another 6,800 cars this year.

City coffers did enjoy an unexpected $1 million increase in revenues from parking meters -- an increase attributed to motorists who pay the meters now for fear of being ticketed or towed.