Transit ridership nationwide last year reached one of its highest points since 1957, according to a transportation trade group. In the Washington region, Metro kept pace with the trend but predicts that ridership will fall this year.

The number of bus and train passengers across the country last year was up 2.3 percent compared with 2010, according to figures released Monday by the American Public Transportation Association.

For subway systems, nationwide ridership was up 3.3 percent. At large agencies, bus ridership was up slightly, by 0.4 percent. Small, medium and large transit systems, as well as commuter bus lines, saw growth, said Michael P. Melaniphy, president and chief executive of the association.

“People are really flocking to transit,” he said.

In places such as Boston, Miami, San Francisco and Nashville, ridership is “outpacing employment,” Melaniphy said. Some riders are being lured by new rail lines in cities such as Dallas and the comfort of new buses and trains.The trend is expected to continue as gas prices rise, the economy bounces back and people use public transportation to get to work, he said.

“They are turning to public transportation as a cost-efficient, dependable, less stressful mode,” Melaniphy said.

Metro saw overall ridership on its buses and trains do slightly better than the national average, rising 2.4 percent in 2011. Rail ridership grew just 0.4 percent, while bus ridership far outstripped the national trend with an increase of 7.1 percent.

Dan Stessel, Metro’s chief spokesman, said the growth was partly “attributable to more favorable weather this winter versus last winter.” Bus ridership, he said, is “increasing at a higher rate because there’s been a population increase in the District, and many of the new residents are very comfortable taking the bus.”

But according to Metro estimates, its rail ridership for fiscal 2013, which begins July 1, may drop 3 percent, while bus use may remain relatively flat.

Metro has been plagued by problems that might be pushing riders away, said Ronald F. Kirby, director of transportation planning at the Metropolitan Washington Council of Governments.

“Here, they’ve not added new rail service,” he said. “There’s been a significant fare hike in the last few years and they’re considering another, and people have lost some of their transit benefits. That’s an enormous hit, and that’s dampening demand.”

Even though Metro is investing $5 billion over six years to fix the deteriorating system, Kirby said the “problems are still there on a day-to-day basis” for riders.

“There are people who are not riding the system because it is not reliable,” he said. “It’s not worth what they have to pay compared to the alternatives.”

There might be more trouble ahead.

The amount of money commuters are allowed to set aside for transit before taxes are taken out of their paychecks fell by $105 this year. Congress is debating whether to increase it. If the increase doesn’t happen, it could mean a decline in Metrorail ridership of nearly 3 percent and a $16 million drop in revenue, according to the transit authority’s estimates.

A possible across-the-board fare increase also could push away riders. Metro General Manager Richard Sarles has proposed the increases in rail and bus fares and parking fees to help fill a $116 million budget deficit.

Metro officials estimate that rail and bus ridership could drop by 1.2 percent if fare increases take effect. But any drop in revenue from lower rail ridership is expected to be dwarfed by the approximately $60 million that a fare increase would generate, Stessel said.

Some riders at six recent Metro hearings on the proposals complained that they do not want to pay more because they think the system is unreliable.

Atlanta’s transit system experienced a loss of riders in 2011 after several years of cutting service and raising fares. The subway there saw a 3.5 percent drop in ridership compared with 2010, according to the transportation association.

That, coupled with a still-struggling economy and a depressed housing market, means fewer people are using Atlanta’s buses and rail, said Ted Basta, chief of business support service at the Metropolitan Atlanta Rapid Transit Authority.

With high unemployment, it translates to “fewer people going to work, and that means fewer people using transit,” he said.