A Metrobus in a parking lot (Courtesy of WMATA)

The Metro board should consider the needs of its riders in setting fares this week, but the transit authority isn’t a social service agency.

Metro must focus on providing the best possible service on its trains, buses and vans, not on deciding whether bus riders are financially needier than rail riders.

Yet the central sticking point among board members involves how to minimize the impact of the fare increases on Metrobus riders, relative to the price of riding Metrorail.

Tom Downs, the board chairman and a District representative with decades of experience in transportation policy, is among those who makes the case for achieving the “right balance from a social equity basis for rail and bus.” A significant portion of bus riders are low-income and are hit by fares that are regressive because everyone pays the same amount, he told the March meeting of the Metro Riders’ Advisory Council.

He described a real need. Transit managers note that some bus riders live so close to the financial edge that even though they use a SmarTrip card to avoid the 20-cent surcharge on cash fares, they still pause at the farebox to load $1.60 onto the card to cover the cost of a single trip.

But systemwide fare increases are a blunt instrument for enhancing economic or social equity.

On March 13, the board reviewed a proposal that increased the bus fare with a SmarTrip card 15 cents to $1.75, and the cash payment from $1.80 to $2. Overall, it’s about a 10 percent increase. The proposed increase in Metrorail fares is 3 percent. Metrorail’s peak boarding charge would be $2.15, which covers the first three miles. Many rail riders would pay more, up to a maximum of $5.90, and many also pay for parking, a cost that would increase 25 cents systemwide.

There was little outcry about any of that from bus and rail riders at Metro’s six hearings on the fare hikes. Most of those who spoke were MetroAccess riders, discouraged that paratransit fares also would rise under a formula that links them to the bus and rail fares.

Regina Lee, a member of Metro’s Accessibility Advisory Committee, a citizens’ panel, was among many who urged the board to consider changes in the formula to reduce the impact on people with disabilities.

These riders, many of whom are utterly dependent on Metro, have an obvious need for assistance. They spoke about having to make difficult choices between the types of medical appointments they could afford to reach.

The board may do something for them, but it’s unlikely to do everything they want. Here, the board members accept a financial reality. It costs Metro an average of $56.97 to provide a paratransit trip, though the most Metro will recover from a rider is $7.

Instead, many board members want to reach out to local jurisdictions to increase their support for paratransit services. That’s a good idea. Why not devote similar energy to developing community support for subsidizing the neediest bus riders?

But the equity issue is just part of what goes into the board’s decision-making.

This is a familiar city versus suburbs fight. The board members representing the core jurisdictions making the heaviest use of Metrobuses traditionally resist bus fare hikes.

The suburbs are home to many of the commuters who pay $4.50 for daily parking at Metro stations, then pay the maximum fare for a long train trip. Their representatives seek to hold down those costs.

There’s an extra element this year. One of the board’s District representatives is Muriel Bowser (D-Ward 4), a council member and candidate for mayor. A key element in her campaign is empowering low-income city residents, and a key element in her approach to the fare increases is protecting bus riders.

In a sense, bus riders already are protected. Even if the board approved all the transit staff’s fare hike proposals, the price of riding a bus would remain significantly below Metrorail fares.

Yet Metrorail riders aren’t any more uniformly high-income than Metrobus riders are uniformly low income.

Junette Wilson of Gaithersburg, a student at Trinity College, is one of those rail riders who gets to the station early, then waits till the lower, off-peak fares kick in before going through the gates. Wilson, who spoke at a fare hearing, calculated her transit costs at $685 per semester. The rail fares are “starting to be unaffordable for a lot of us,” she said.

Helping other people get around is the right thing to do, whether it involves aiding a rider on a platform or assisting the needy in covering their transit costs. The benefits bounce back. Ensuring that people can get to their jobs and medical appointments boosts the economy and enhances the general welfare.

That’s a task for the entire region — its governments, social service agencies and individuals. The transit authority can’t fine-tune its fares well enough to achieve this goal.

Dr. Gridlock also appears Thursday in Local Living. Comments and questions are welcome and may be used in a column, along with the writer’s name and home community. Write Dr. Gridlock at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071, or e-mail drgridlock@washpost.com .