A story in yesterday's editions incorrectly said that Turner Harris, a former assistant supervisor for the D.C. Transportation Department's parking meter collection unit, pleaded guilty to larceny of the money. He was found guilty of the charge by a judge after an uncontested statement of facts in the case was submitted to the judge.

The D.C. government collected nearly $1 million more in parking revenues last year than in 1975 with some of the increase due to improvements in a collectin system that had been losing an estimated $500,000 ayear, transportation director Douglas N. Schneider Jr. said yesterday.

During the 1976 fiscal year, Schneider said, $2.3 million in nickels, dimes and quarters was collected from city parking meters compared to $1.3 million for the previous fiscal year - an increase of 74.8 per cent.

John Brophy, head of the Transportation Department's parking branch, said $3 million in meter revenues is expected "the current fiscal year, which ends Sept. 30.

A 21-month grand jury investigation that ended early last year found that between $2 million and $5 million in meter revenues had been embezzled by city employees over a 10-year period. Investigators said the losses were possible by widespread mismanagement in the parking meter collections system.

During the course of the grand jury investigation, Turner Harris, a former assistant supervisor in the collection unit was arrested and charged with larceny, after police entered his home and found more than $2,000 in coins. Last November, Harris pleaded guilty to the charge.

Two other city employees were later arrested and also charged with larceny. But those charges were dropped, and the men were placed on 30-day suspension from their jobs.

In March, Mayor alter E. Washington approved a series of recommended changes in the collection system. Some of those changes - including the use of a private guard firm to make the collections instead of city employees - were not in effect when the revenue increases occurred. But those changes that were operative, Schneider said yesterday, had some part in the revenue increase.

"How much of the additional revenue you can attribute to the additional attention we're paying to security, I don't know," Schneider said, "But obviously it had some effect."

There were several nonsecurity factors that may also have played a part in the boost in meter revenues, Schneider said. The city increased from 29 cents to 40 cents the hourly parking rate at about 3,000 meters in the downtown area. In addition, 2,000 new meters were installed in various parts of the city during 1976, he said.

But, Schneider said, other meters were removed to increase bus parking space during the Bicentennial, and that action reduced the amount of revenues for the city.

Among other steps that have been taken and that would have affected the increase, Schneider said, is a reorganization of the meter maintenance shop that has improved upkeep of the city's 10,000 meters.

Before the reorganization, 10 per cent of the meters were likely to be out of operation on a given day. That figure has been reduced to 1 per cent, Schneider said.

He said the city also has developed a better system for keeping track of who has keys to the meters. The grand jury had found that an unspecified number of master keys to the meters and locked coin boxes in which the coins are stored had been lost or stolen.

The Transportation Department also has a three-member staff monitoring the collection, counting and storage of meter money, Schneider said.

Brophy said optimistic forecasts for large collections during the current fiscal year could be dimmed by the unseasonably cold weather that occurred during part of the winter.

Last month, for example, only $164,686 was collected, down $37,187 from the previous January, he said.