The cost of transporting District of Columbia employes on shuttle buses has been reduced to the point where it is almost as cheap as taking a taxi-cab, according to a new report on municipal efficiency.

In the first half of the 1977 fiscal year, each trip on a shuttle bus cost the city government $2.86. In the second half of the year, the service was expanded and reorganized, and the cost for each trip dropped to $1.45.

This compares with $1.10 for a single-zone ride in a taxicab, and 40 cents on a Metrobus.

According to the report, released over the weekend by Mayor Walter E. Washington, the reduced cost for each trip was not the result of lowered expenses. It happened because nearly twice as many employes decided to ride the buses, which interconnect D.C. offices in the downtown area.

The 80-page report, titled "Improving Program Performance" and prepared by the D.C. Office of Budget and Management Systems, also disclosed that city parking meter revenues have more than doubled in the two years since some city employees were found to be systematically stealing from the meters.

The city's, 1,100 meters took in $2.8 million in fiscal 1977. In 1975, before the thefts were found and a new security system was established, the meter income was about $1.3 million.

The lowered cost per rider of shuttle bus transportation was one of the items singled out by the mayor in a letter transmitting the efficiency report to the City Council.

For many years, city employes who needed to travel between buildings were sent in automobiles individually dispatched from a motor pool. In 1975, there were 47,000 such trips, and each cost $4.80.

Five small shuttle buses, operating on a single loop through the downtown, carried about 53,000 employes in 1975, an average of only 211 per working day. By 1977, the cost of each employe's bus trip had risen to $2.86.

After an analysis it was decided to expand the fleet to eight buses, all of them new, and to assign them to three routes, each designated by a color code.

One result was higher costs, because there were more buses. Another result was a lower average cost for each rider, because there were nearly 11,000 riders a month where there had been only 6,000 previously.

According to the report, the analysis ruled out Metrobus service (the routes do go to the right places), increased use of drive-yourself cars (parking problems) and taxicabs (problems with administrative control).

Expansion of the bus sytem is expected to reduce the number of individually dispatched automobile trips from the previous 47,000 a year to about 28,000, mostly to destinations outside the downtown area. This freed six drivers, three of whom were transferred from driving automobiles to driving buses. Two others resigned and one was reassigned to other duties.

There were among other finding in the efficiency report:

More traffic signals are breaking down as the devices get older, and it now takes longer - 75 minutes, instead of 61 minutes in 1976 - on the average to repair a malfunctioning unit. Plans will be prepared for better preventive maintenance.

The number of accidents involving fire trucks and other Fire Department vehicles has dropped 41 percent in two years, the apparent result of safety programs. A total of 67 accidents were reported in 1977.

A better standby system has reduced the time police officers spend in court by 15 percent, to 322,269 hours in 1977.

Escapes from the city's jails and prison declined from 29 in 1973 to none in 1977, partly the result of improved security precautions.

Complying with a court order, the Department of Human Resources is processing its largest category of public welfare applications 15 percent faster than it did in 1976 - from 777 a month in 1976 to 894 in 1977.

The Department of Manpower placed 6 percent more individuals (a total of 21,634) in jobs despite a 29 percent decline in the number of job openings listed during 1977.

The Department of Finance and Revenue has eliminated its backlog of 2,995 bad checks totaling $700,000, and takes immediate steps to collect on the 30 bad checks it receives every day. Anybody who writes a check that bounces must pay the city a $5 penalty.

The Department of Environmental services caught up on its issuance of water bills, is working to create a fully automated system.

The mayor claimed credit for the expected future efficiency of a civilian (rather than police) parking-enforcement program, which has not yet been enacted by the City Council.