Sara Cassio was planning to visit with family and friends in Mesa, Ariz., over the Memorial Day weekend, but high gas prices will keep her home in North Salt Lake.

"I was going to drive down there with my roommate," she said. "I'm from Mesa."

When Cassio realized the cost of gas made driving too expensive, she checked airfares but discovered that they, too, have increased with rising fuel prices. "It was even worse than gas," she said.

On Thursday, the average price of a gallon of unleaded gas in Utah was $3.74. Nationally, a gallon cost $3.83, a record high.

Oil prices also have broken records during the past week. On Thursday, July Brent crude futures settled at $130.51 a barrel on the ICE Futures Exchange. Oil prices overnight Thursday reached a record high of $135.09 per barrel, leading many analysts to speculate that gas prices will soar above $4 a gallon in coming weeks.

A poll conducted this month for the Deseret News and KSL-TV found that 63 percent of Utahns said they have changed their driving habits in recent weeks as a result of gas prices. Among those surveyed, 46 percent said they have "definitely" changed their habits, and 17 percent said they have "probably" done so.

Pollster Dan Jones & Associates interviewed 604 Utahns between May 13 and 19. The margin of error for the poll was 4 percent.

Among the 380 Utahns who said they have changed their driving habits, the majority — 95 percent — said they were driving less. Sixty-one percent said they were reducing their driving speeds, 29 percent said they were carpooling and 8 percent have begun using more mass transit. The margin of error on that sample was 5.1 percent.

Jared Tadehara of Murray began carpooling with his mother to work at the Salt Lake City nursery Louise Gardens, and he carpools to Salt Lake Community College with friends. He also rides TRAX to get downtown.

Gas prices, he says, are affecting his summer vacation plans. Typically, summertime for Tadehara means weekend road trips with friends to Wyoming, Idaho and St. George. But not this summer.

"I'm going to try to stay around here as much as possible," he said. "I'm trying to get into biking. We'll see how it goes."

Tadehara's altered vacation plans are not unusual. The Dan Jones poll found that 49 percent of Utahns said they were scaling back on summer vacation plans. Thirty-six percent said they "definitely" were changing their plans, and 13 percent said they would "probably" do so.

To cope with the rising costs, 22 percent of Utahns in the survey said they are using credit cards more to pay for gas. Among that group of 134 Utahns, 85 percent said they were "definitely" or "probably" able to pay off their credit-card balances for fuel each month. The margin of error for that group was 8.5 percent.