When it comes to transit fares, what goes up rarely comes down. But the San Francisco Municipal Transportation Agency is considering reducing some fares — especially for visitors and for those who rely on monthly passes.

Muni also plans to introduce a day pass to lure more riders.

The MTA Board of Directors will discuss the possible fare changes Tuesday as part of its budget planning process, which will also include consideration of increased fees for everything from residential parking permits to parking citations. The agency needs to close an anticipated $23 million gap for the coming budget year that starts July 1 and $20 million for the following year.

The deficits are the result of a variety of factors, including free fares to low- and moderate-income youth, seniors and disabled riders, reductions in towing fees for low-income drivers, an increase in the number of MTA staff, and pension and health care costs.

The expected shortfall doesn’t take into account the costs of opening the Central Subway in 2019, increasing rail service as new Muni Metro cars arrive and addressing equity issues in transit service levels. Those could increase the deficit to $35.9 million in the 2019 budget year and $63.1 million the year after. The agency’s annual budget is about $1.2 billion.

Balancing the budget will require what the agency describes as some difficult choices, including strategic cuts and efficiency improvements, as well as the use of some reserve funds to cover one-time expenses and the use of some funds tied to population growth, to cover operations instead of capital projects.

Not surprisingly, some fare increases are being proposed, but the MTA also hopes that decreasing some fares will draw new riders and reduce the expense of processing cash taken in primarily from day riders.

The biggest fare hike would be in the cash fare for riding Muni. It’s now 25 cents more than what Clipper card and MuniMobile mobile phone app users pay. The transit agency is considering raising that differential to 50 cents, which would make a single ride on the bus or Muni Metro $3 for those paying cash.

Muni would limit the planned price increase for the monthly Fast Pass that includes BART rides within the city limits to $15, or 20 percent more than the pass that includes only travel aboard Muni. The result would save those riders $1; they’d pay $93 instead of a $4 inflation-based price increase that had been planned.

Since 2013, sales of those passes have dropped 28 percent.

Visitor passports, which offer unlimited rides for one, three or seven days, would drop sharply under a proposal to discount passes purchased and loaded on Clipper cards and the MuniMobile app.

Now $22 for a single-day pass, including cable car rides, $33 for three days and $43 for seven days, the price would drop to $12 for one day, $24 for three and $39 for seven — if purchased electronically. Passports bought in person, with cash or credit cards, would cost $23, $34 and $45 respectively.

Muni is also proposing a new type of fare — a one-day pass valid for unlimited rides except on cable cars — and priced at a rate equal to 2.5 rides, or $6.25.

Day passes are common at many transit agencies, including AC Transit, which charges $5, and the Santa Clara Valley Transportation Authority, where passes cost $7. Nationally, day passes range from $5 in Portland, Ore., to $10 in Chicago. Initially, the passes would be available only on MuniMobile.

In addition to rejiggering fares, the MTA board also will consider raising dozens of fees that are limited to covering costs. They include the annual residential parking permit, which would rise $8 to $136; the boot removal fee, which would increase $40 to $505; and cable-car rental charges, which would rise $107 for two hours to $892.

“This is another step in the overall process of sharing the agency’s vision of the transportation system and to hear from the public about what they want,” MTA spokesman Paul Rose said.

The MTA Board of Directors must finish its budget and submit it to the Board of Supervisors by May 1. The supervisors can either approve the MTA’s spending plan or reject the entire document and send it back for revision. They’re not allowed to accept and reject portions of the budget.