PROVIDENCE -- By the time the Chalkstone Avenue bus reached Fern Street on its way downtown a few mornings ago, Missy Smith, who was headed for a doctor's appointment, was already standing. A bit closer to Kennedy Plaza, all the seats were full and more people were standing.

Journal photo / Mary Murphy

The seats are full Friday morning on RIPTAs Route 56 bus on Chalkstone Avenue to Kennedy Plaza in Providence. Sales of monthly passes and discount ticket books are up sharply, and the ridership increase is taxing the mass transit system.

Often these days, driver Michael Rose said, "It's packed to the doors."

Across the state, bus ridership has shot up a remarkable 24 percent in the wake of Hurricane Katrina and the jump in gasoline prices, Rhode Island Public Transit Authority officials say.

The surge in ridership has left many buses jammed and forced drivers to leave passengers by the roadside.

RIPTA isn't unique. The ridership increase is "coast to coast," said Virginia Miller, a spokeswoman for the Washington, D.C.-based American Public Transportation Association. "It's in all areas in the country, and it's in big cities and small."

In Rhode Island, the new riders offer an extraordinary, perhaps unique, chance for RIPTA to achieve a long-term increase in ridership, something transportation officials, planners and environmental advocates all want.

State plans for cleaner air and less-congested highways rely, in part, on increased public transit use. The state Department of Transportation is often identified with road building, but James R. Capaldi, the DOT's director, said at a recent RIPTA board meeting that while Route 95 is getting more congested, "I have no plans to widen it." The future of ground transportation, Capaldi said, is in trains and buses.

But the opportunity isn't easy to grasp, and buses will probably stay crowded. For the moment, at least, RIPTA is scrambling to accommodate new customers without spending much extra money, for fear of upsetting state officials unhappy at RIPTA's past deficit spending.

"I'm happy, but I have to worry about meeting my budget, too," said General Manager Alfred J. Moscola.

RIPTA HAS no complete count of riders because only a handful of buses are equipped to count every passenger, including those using passes.

Mark Therrien, the agency's assistant general manager for planning, said he compared the ridership on 689 specific weekday bus trips since Aug. 30 with the same days' trips 12 months before. That showed an average ridership increase of 24 percent. Across the system, he said, that translates into about 15,800 additional one-way weekday rides, for a total of about 72,000 rides per day.

Therrien said that other factors suggesting a sharp ridership increase include a 55-percent increase in monthly passes sold in September compared with last year, and a 50-percent increase in revenue from sales of RIPTIKs, tickets sold at a discount in packs of 10. (RIPTIKS are $13.50 for a pack of 10 compared with the $1.50 cash fare.)

The ridership increase is taxing the system. Therrien said that trips that used to be crowded are now forced to leave passengers to wait for the next bus. On the Chalkstone Avenue bus, which Rose drives from 5 a.m. to 1 p.m., "I have three or four trips when it's packed to the doors."

Passengers are all supposed to be behind the yellow line, at the driver's seat. But even bending the rules, Rose said, "Sometimes I can't pick everybody up. I hate to go by people -- it's a problem for them."

Therrien said the express bus from the Westerly park-and-ride lot to Kennedy Plaza was one of the system's most crowded lines. Last spring it was carrying about 20 passengers each way. But by September it averaged more than 75 passengers, prompting RIPTA to add a second bus.

Buses are also running late because it takes longer for more people to get on and off, he said. That is eroding the "fallback" time built into route schedules to make up for traffic delays while keeping on time, or to give drivers a break.

The agency had been operating with barely enough buses to handle the regular ridership. Happily, the ridership increase came just as RIPTA was getting 36 new buses. "It comes at a good time as far as equipment is concerned," Moscola said.

But solving the crowding problem by adding service, a RIPTA staff report says, would require 26,600 additional hours of bus service per year. That would cost an extra $1.8 million that RIPTA does not have.

RIPTA HAS BEEN under increasing financial and political pressure. A series of budget deficits and threatened service cutbacks brought difficult relations with the governor and General Assembly before they rescued the agency with extra funding. The Assembly has ordered a study on whether to end RIPTA's independence by folding it into the DOT.

Therrien said Moscola has promised the state's political leaders that he would not expand service unilaterally.

"We have a commitment to the governor and the legislature to run steady-state service until we talk to them," Therrien said.

"We could add 40 [runs] tomorrow, and there'd be plenty of people on them," he said. But he said RIPTA needs to demonstrate "that we're not just throwing money at the problem."

So far, Therrien said, RIPTA has added only four buses and is trying to deal with crowding with a variety of adjustments like shifting buses from routes, or parts of routes, with lower demand to those under more pressure.

However, "We're getting trips that are so heavy that the drivers aren't getting out of their seat" for a whole eight-hour shift, said Stephen Farrell, president of Local 618 of the Amalgamated Transit Union, which represents the drivers.

Whether juggling existing service can satisfy riders, new and old, without a substantial spending increase isn't clear.

Asked if would-be passengers can expect to continue to see packed buses drive by them rather than stopping, Therrien said, "Hopefully not. We're doing everything possible to make sure that doesn't happen."

Asked if people can expect to be standing on buses through New Year's, Therrien replied, "On a lot of buses, yes."

ALTHOUGH RIPTA ridership had been gradually rising, the gasoline price increase has done something years of advertising hasn't: given RIPTA a chance to sell itself to thousands of new riders. But it's not clear whether gas prices will remain high, nor whether many of the new riders will stick with transit if prices fall.

Unlike many RIPTA customers who have no other transportation choice, most of the new riders are people who can take RIPTA or leave it, Moscola said.

"I think the new folks are people with cars that say, 'Let me try this,' " Moscola said.

But Moscola is optimistic. "I think once we get people on the buses to try them, we can keep them," he said.

Therrien said that based on the trend of his ridership data, matched with gasoline prices, the signs are good.

Gasoline prices peaked in the first week in September, then retreated. But Therrien's figures showed ridership continuing to increase through the end of September.

What happens next depends on the price of gasoline, RIPTA's ability to respond to its new riders and what the riders make of it all.

At least some of them are pleased.

As she was getting off the Chalkstone Avenue bus at the Veterans Medical Center, a woman in a black leather jacket gestured toward Rose as she passed a reporter and photographer on the way to the door.

"Give these guys credit -- they're great," she said.