A tall man in a brown suit squeezed his way through a crowd of 250 worried Metrobus riders at a public hearing in Silver Spring this week to plead for his son, a 35-year-old mentally handicapped resident of Inwood House on University Boulevard.

"Without the bus, my son can't get to his job at the National Institutes of Health," said William W. Brownholtz, a concerned father who protested a proposed fare increase and the possible elimination of the C-2 bus line that carries his son to work.

His plea came during one of a recent series of unusually crowded public hearings in Metro subway fares and the future of 38 of Maryland's Metrobus routes. The hearings will conclude tonight at Largo Senior High School in Upper Marlboro where a proposal is on the docket to end bus service after 8 p.m., and on weekends, throughout Prince George's County.

Brownholtz said his son is one of 175 residents at Inwood House, a federally subsidized home for the handicapped who have decided to tackle living on their own.

"With public transportation available, our residents are proud of what they can accomplish, rather than being depressed by their handicap," added Thomas D. Woodward, the resident services coordinator at Inwood House. Woodward testified that 75 of the Inwood House dwellers rely on Metrobuses for their transportation.

The Inwood House residents, however, are not the only people irritated by the prospect of higher bus fares throughout the system and the elimination of routes C-1, C-2 and C-4, among others.

The C-2 line starts at Montgomery Mall, passes the National Institutes of Health, Wheaton Plaza, Langley Park, the University of Maryland, and ends at Beltway Plaza. C-1 provides service from Glen Echo to Wisconsin Circle in Frienship Heights. And C-4, the Randolph Road line, winds its way through Rockville, Viers Mill Village and Colesville to White Oak Shopping Center.

"We fear the effects on traffic of a new Metro fare increase," said Lance Compa of the Takoma Park Citizens Traffic Committee. More expensive bus rides, said Compa, will prompt hundreds of commuters to switch back to their automobiles.

Metro is forecasting a budget that will be $12 million short this year unless the eight contributing local governments increase subsidies. Cleatus E. Barnett, the board chairman of the Washington Metropolitan Area Transit Authority (WMATA), told the audience at the hearing that the alternatives are service cutbacks, fare increases, or higher subsidies from local governments.

The major contributors to the budget shortfall are contractually required cost-of-living pay increases for Metro's 5,000 bus drivers, train operators, station attendants and mechanics, an unexpected need for spare parts for buses and the rising cost of diesel fuel.

Bethesda resident Robert Kerensky characterized the move to shut down routes -- especially the C-2 line -- and to increase fares as "criminal."

"We speak about our concern for the poor and disadvantaged minorities, but we raise fares and eliminate routes that provide access to gainful employment," he said.

Several speakers, including Montgomery County Council member Esther Gelman, who said she came to represent herself and not the county, warned Barnett against insensitive mass transit planning.

"I don't think we want to make it harder for people to use the system that they paid for," said Gelman, to loud approval from the crowd.

In reply to the steady stream of calls for helping low-income and handicapped wage-earners who ride the endangered lines, Barnett said the decision is strictly a matter of cost.

"There seems to be a great deal of support for these lines. But this is a fiscal issue. These are heavily subsidized lines," added Barnett, who is a voting member on the six-member WMATA board.

Metro cost studies estimate that the subsidy per ride is $1.08 on C-1, $1.39 on C-2 and $1.09 on C-4.

But daily Metrobus and Metrorail users such as Eloise Ullman oppose rate hikes, especially on the subway's Red Line, which is scheduled to expand to Bethesda by 1983. Instead, Ullman, a Wheaton resident, asked for lower fares for commuters.

"My government has said it will provide quick, cheap, reliable transportation, by using mass transportation," she said.

"A fare increase is not the answer to Metro's problems and, in my opinion, will only serve to augment them," added Ullman, who said she wants Metro to build up ridership, not curtail it, in preparation for subway expansion.

An additional loss of $3.7 million is foreseen if Congress, as expected, cuts the Carter administration's recommendation for public transportation operating funds.

Although she admits it's highly unlikely that Prince George's County will elect to follow the county staff proposal to halt service after 8 p.m. and on weekends, Dee Allison, Prince George's transit director, said many of the existing routes are highly underutilized and face elimination.

David LaPlaca, the Prince George's alternate member on the WMATA board, said the county's 1980 transit deficit is $15 million, and warned: "At that rate it will be $100 million in ten years."

To solve its current budget crunch, Metro wants to standardize all one-zone bus fares at 60 cents throughout the metropolitan area. This would raise the existing non-rush hour cost of a one-way trip in Maryland, now 45 cents, by 15 cents. The cost of crossing the District of Columbia line from Maryland would rise from 25 to 35 cents. Peak hour bus fares would remain at 60 cents; but the 20-cent charge for crossing from Maryland to Virginia would increase by a dime, according to Metro cost estimates.

Another 10 cents would be added to the existing fare of 15 cents for transferring from subway to bus.

Base Metrorail fares during rush hour are proposed to go up a nickel from 55 to 60 cents, and the charge for traveling more than three miles would increase from the current rate of 11.5 cents to 12.5 cents per mile. In off hours, the flat rate on Metrorail would jump from 50 cents to 60 cents for all trips, regardless of length.

The cost of parking at a Metro lot would be changed to $1.25 a day at all Metro lots. The daily rate currently is 75 cents at the New Carrollton station lot and $1 at all other stations.

Another possible change involves the cost and value of flash passes, the color-coded cards that provide riders with two weeks of bus service for $18 in Maryland and Washington during rush hours.

As a bonus, Metro has given $5 dollars of Metrorail service to purchasers of the flash passes, small cards that are compatible with both Metrobus and Metrorail systems. But the proposal would eliminate this "extra" $5.

Metro spokesman Cody Pfanstiehl said the final decision on routes, cutbacks and fares rests with the Montgomery and Prince George's county councils and other participating jurisdictions.

Metro financial planner John Fularz said local governments will have to increase their subsidies if all existing service is to continue. Any service changes, he said, would take effect in January.

In the face of reduced service, one Inwood House resident expressed her opinion in a poem:

I'll make a fuss if you take away the C-2 bus.

We need it every day. So let the C-2 stay."