More people in the New York region are taking public transportation to and from work but rising gasoline prices are only one of the reasons behind the shift toward buses and trains, transit officials say.

On top of record-breaking Long Island Rail Road ridership last year, the Metropolitan Transportation Authority yesterday reported even more riders rode the rails in the first three months of this year.

The cost of filling the tank, however, is not necessarily the biggest factor behind the increase, an MTA spokesman said. The price of gas - now over $4 a gallon at some stations - is only the latest development that may give some commuters an excuse to give up their cars.

"Gas prices remain a factor for customers, but not the only reason," MTA spokesman Aaron Donovan said.

In February, LIRR President Helena Williams said the growth was also a result of improved on-time performance and job growth in New York City. Yesterday, the MTA listed a host of other factors for the growing popularity of mass transit, including cleaner facilities, a reduction in system breakdowns, environmental awareness and traffic congestion.

Ridership on the Long Island Rail Road was up 5.3 percent for the first three months of this year compared to the same period last year, the railroad said. The MTA yesterday reported ridership increases on all of its services for the first three months this year.