NEW YORK » Subway and bus fares will rise again in March. The only questions are by how much and for which riders.

When the Metropolitan Transportation Authority’s board members meet this week, they are expected to discuss proposals for a 4 percent increase in fares and tolls across the system’s trains, buses, tunnels and bridges. The fares are scheduled to rise every two years as part of the authority’s long-term revenue plans, but details of the upcoming increase are still being worked out. Riders will have a chance to weigh in at public hearings next month.

One proposal would raise the base fare for subways and buses by 25 cents to $2.75, while increasing the bonus on pay-per-ride MetroCards to 11 percent from 5 percent. A second proposal would keep the base fare at $2.50, but reduce the current pay-per-ride bonus.

Under both plans, weekly and monthly MetroCards would cost more, according to Mitchell H. Pally, a longtime board member who confirmed the details of the proposals, which the authority has not released publicly yet. Weekly passes would go up by $1 to $31, and a monthly pass would increase by $4.50 to $116.50, Pally said. There would be a similar 4 percent increase in fares and tolls for rail lines and tunnels and bridges.

Two years ago, the board considered eliminating the pay-per-ride bonus, which gives riders an extra $1, for example, when they put $20 on a card. But after a public outcry, the authority agreed to continue the discount. Transportation advocates say that it is an important benefit for low-income riders who cannot afford weekly or monthly passes.

An earlier plan proposed a 7.5 percent fare increase for 2015, but that was scaled back because of an improved financial outlook, with higher than expected passenger and real estate revenues, the authority said. Last year, the base fare rose from $2.25 to $2.50, under a 7.5 percent increase in revenues. The pay-per-ride bonus was lowered from 7 percent to 5 percent.

The board is expected to vote on the fare increases in January, and they would go into effect March 1. Another 4 percent increase is scheduled for 2017.

Adam Lisberg, a spokesman for the authority, said that the agency had not finalized the specific proposals for how the increases would take effect. He noted that the increases amounted to "only 2 percent a year" and that was possible because the authority had trimmed more than $1 billion from its annual expenses.

Gene Russianoff, the staff lawyer for the Straphangers Campaign, a riders advocacy group, said he supported the proposal with the increase for the pay-per-ride bonus because it was important to continue to offer a good discount for the low-income riders who use it. Many riders are frustrated that fares are rising again, he said, noting that it will be the fourth increase in seven years, Russianoff said.

"People are not going to be happy about it, but the question is whether they are going to do anything about it," he said. "It’s a pretty modest fare increase."

Altogether, the changes to fares and tolls are expected to generate $234 million for the authority in the 2015 calendar year. About $139 million will come from New York City Transit. Another $51 million will come from tolls on bridges and tunnels. The rest will come from Long Island Rail Road, Metro-North Railroad and other services.

Even as fares have risen, the number of riders using the subway continues to climb. More than 6.1 million people rode the subway on Sept. 23, the highest single-day number since the authority started collecting the figures almost 30 years ago.

At the same time, the authority is wrestling with an even bigger question over how to fund its five-year capital plan, a $32 billion proposal to keep the aging system running and to pay for new projects. The plan has a funding gap of $15 billion, and board members have argued that the authority needs to look at new sources of revenue and to appeal to state and city lawmakers for more funding.

The state comptroller, Thomas P. DiNapoli, has warned that if the authority closes the gap with additional borrowing, it could increase pressure to raise fares and tolls more than those scheduled.

The recently reopened Fulton Center in Lower Manhattan showed the promise and the challenges for the large-scale projects the authority has taken on. The shiny complex, part of which was destroyed in the Sept. 11, 2001, terrorist attacks, received positive reviews, but it opened seven years late and cost $1.4 billion, nearly double the original budget.

Even Russianoff, a frequent critic of the authority, said that any long-term rider of the subway had to acknowledge that it had improved substantially in recent years.

"We New Yorkers are a grudging lot, and we find it hard to admit that our public services have gotten better," he said.

© 2014 The New York Times Company