Jessica Hanson is looking forward to gas prices falling 50 cents a gallon next week and found herself yesterday trying to survive on the last remaining drops of precious fuel left in her 1989 Mazda 323.

Like drivers across the Islands, Hanson filled up last weekend anticipating the rise in prices on Monday. She's now trying to squeeze by until next Monday, when prices are expected to fall.

"I hope I can make it," Hanson said yesterday, "because I'm down to the very end."

The state Public Utilities Commission said yesterday the maximum wholesale, pre-tax price of a gallon of regular unleaded gasoline will fall by 50 cents on O'ahu beginning Monday. To drivers that means they could pay about $3.11 per gallon — compared to this week when some dealers charged as much as $3.69 per gallon.

Since Sept. 1, when Hawai'i became the only state in the nation to impose a gasoline price cap, drivers have been able to anticipate price changes based on the state's weekly announcement. Each Wednesday, the state posts what the maximum wholesale price for gas will be for the following week.

As prices bounce up and down, several drivers yesterday said they're adjusting both the timing of their gasoline spending and their driving habits depending on where fuel prices are heading.

Hanson, a Hawai'i Pacific University student and a manager at Duke's Canoe Club, drives from her home on University Avenue to go to school at HPU's downtown campus. But to get to work, Hanson car pools with her roommate, a dinner server at Duke's.

"For school, I have no choice. I have to drive," Hanson said. "But I car pool whenever I can."

Like Hanson, Ryan Tokumura, an associate in an actuarial firm, filled up last week "anticipating prices would go up — and they did."

And like Hanson, Tokumura is also trying to hold out until next week before filling up his 1998 Toyota 4Runner.

"I'm waiting until Monday," Tokumura said. "I hope I can make it. I'm trying not to drive too much."

While it is inconvenient for some drivers, the price swings could lead to real headaches for gas-station owners like Barney Robinson, who owns Chevron stations in Kahala and near Honolulu International Airport.

If prices fall next week as expected, Robinson could find himself selling the old gasoline he bought at a higher price to customers who are expecting a new, reduced price.

"I have no choice but to pass the savings on when I can, even though I bought it at a higher price," Robinson said.

Robinson has the capacity to hold 30,000 gallons of fuel at his stations and likes to keep a minimum of 10,000 gallons in reserve.

"What I don't want to do is end up tying up dollars in the ground unnecessarily," Robinson said. Next week, "I will have gasoline in the ground at the old price and if I lower my price 50 cents a gallon, I will be selling at 50 cents below what I bought it. If you take 10,000 gallons times 50 cents, that's $5,000 — and that's a lot of money."

Station owners are already seeing the impact of the changing habits of drivers as they adjust to the gas cap.

Bob Swartz, who owns Chevron stations in Kalihi, Kane'ohe and Kailua, saw sales drop 10 percent to 15 percent at one of his stations on Monday and about 20 percent at another. Business held steady at the third. Monday was the day the price for regular on O'ahu went from around $3.16 to about $3.62.

"People are paying attention to what's going on," Swartz said. "All that's going to do is create all kinds of delivery problems and possible supply problems where you've got no place to put the gasoline and then all of a sudden you need gasoline and there isn't enough."

Not all drivers are adjusting their buying habits. Among them: Dylan Ching, whose wife, Kanoe, kept pushing him to fill up his 2001 Ford F-150 truck last weekend before Monday's price increase.

Ching listened — but failed to follow his wife's advice.

"She was all about, 'Fill up, fill up' and I didn't do it," Ching said. "Now she's telling me to hold off until next week. But if I need gas, I need gas."

Marc Lum, a property manager who lives downtown, said, "I don't pay too much attention to it. You gotta do what you gotta do. It doesn't make sense to me to try to save 60 cents by driving 10 miles to get it."

But others like Ward Fukunaga from Kaimuki represent a new generation of drivers who suddenly find themselves basing their gasoline purchasing power around the rise and fall of Hawai'i's gas cap.

Fukunaga even finds himself spending more time at home watching TV instead of going out with his friends like he usually does at night and on the weekends — all to cut down on his gas consumption.

"I now drive as little as possible," Fukunaga said. "If I don't have to do it, I don't drive."

And for the rest of this week, Fukunaga will find himself coaxing what gas remains in his 2001 Nissan Frontier truck until fuel prices fall again.

"If I can," he said, "I need to make it until next week."

Reach Dan Nakaso at dnakaso@honoluluadvertiser.com.