Gasoline prices this week reached a new record average of $4.02 per gallon, according to the AAA Fuel Gauge Report.
Two-thirds of Americans have already changed how much they drive due to high prices at the pump, according to a poll commissioned by Access America Travel Insurance and Assistance.
Seventy-four percent of those polled said they would drive less, once gas hits $4 per gallon. Eighty-five percent said $5 costs per gallon would motivate driving changes.
The median price to spark a shift in driving habits was $3.20 per gallon, which was near the average several months ago. Gas prices have risen by 29 percent in a year, according to the American Automobile Association.
However, 9 percent of respondents said no amount of sticker shock at the pump would change the way the drive.
To save money, 26 percent of people surveyed said they'd reduce recreational driving, and 21 percent said they would try to run multiple errands at once. Only 7 percent named carpooling as an option, followed by 6 percent claiming that they would walk or bicycle more.
Among the first people to adjust the way they get around are those in homes earning less than $50,000, as well as Southerners, parents of children younger than 18, and "those saying the country is headed on the wrong track," according to Access America. Public transportation was favored most by people earning less than $25,000.
The telephone survey of 1,000 adults was conducted by Ipsos Public Affairs between May 30 and June 2.
Dealers report a short supply for hybrids, which people are waiting months to buy.
In January, 44 percent of respondents to a survey told trade group Hybrid Owners of America that they would consider buying a hybrid, once gas topped $4 per gallon.
Diesel, at $4.79 per gallon, costs even more than gasoline, according to the AAA.
Prices have also skyrocketed in the past year for biodiesel and other biofuels, which are increasingly demonized for driving up food prices. Waste vegetable oil, which restaurant owners used to beg green gearheads to haul away for free, is fetching high prices.
Web sites including GasBuddy.com help locate less-expensive gas- and diesel-filling stations.