Ridership on Prince William's commuter bus system has risen to record levels because of high gas prices, new buses and construction on I-95, but the region's financial pinch could prevent further growth.

Nearly 250,000 people rode Commuteride's rush hour routes to Washington, the Pentagon and Vienna in the fiscal year that ended in June. That's an average of 1,000 commuters each weekday, up from 900 daily passengers in the previous year, according to the Prince William Planning Office.

The Persian Gulf crisis and the accompanying rise in gasoline prices pushed those numbers even higher.

"We gained 150 riders in one day," said Stephen Rowland, senior transit planner. Ridership is hovering around 1,200 daily passengers, even though August is traditionally a very lean month for the bus system.

"If we're carrying that many right now, we're going to be really full come September," he said.

Planners are trying to keep pace with the demand, replacing old buses with new ones with working air conditioning, a major selling point in the summer months, and expanding service.

Over the last year, Commuteride has added nine morning routes and 11 evening routes, bringing its total offerings to 34 morning and 38 evening runs. Buses now come every 15 minutes on some of the most popular routes, those that serve Lake Ridge and Dale City.

But the buses are still crowded. The evening runs average 95 percent of seating capacity, so many of the more popular buses are filled with standing passengers.

"We've got more people that want to ride the bus than we have seats for them," said Steve Dixon, who heads the county's Mass Transit Committee. Some transit planners worry that some would-be passengers will be driven away if they have to stand for the entire ride, which takes more than 45 minutes.

The crowding problem is acute on early morning and late evening runs right now, Rowland said. "We have so many {Department of Defense} employees that are working long hours because of the Iraqi situation."

But further expansion will not be easy.

"Given the budget situation in Virginia," Dixon said, "it may be difficult to add service.

"We're getting about the maximum routes we can out of the equipment we have."

Buying new equipment will be virtually impossible because Commuteride is already facing cutbacks in the funds it gets from both the state and the Potomac Rappahannock Transportation Commission, a multi-jurisdictional transit committee.

Fares will cover only about half of the system's $2.6 million operating budget this year, with $624,000 coming from the state Department of Transportation and $682,000 from the commission, said commission planner Randall G. Farwell.

The state has already taken back the real estate transfer tax money that county officials had hoped to use for an intra-county bus system, and the state secretary of transportation has announced cutbacks in some local grant programs. Prince William officials don't know whether Commuteride is one of the programs vulnerable to cuts.

Commission money is also in short supply because the panel has begun channeling its money toward getting the state's first-ever commuter rail service to the District ready for its debut in October 1991. Last year Commuteride received $1.86 million from the commission, but this year, the bus system will get only $682,000, Farwell said.

Fare increases are a likely result, and the system has recently bought fare boxes to improve collection. For five years, tickets have been $5 a ride, $28 for a book of 10. "If state funding is seriously cut, we're going to need to make it up, and {charging} riders is usually the way," Rowland said.