“I used to fill it up pretty regularly, but now I drive it until the tank is almost empty, looking for the cheapest place to buy gas,” said Ms. Berry, who drives a beat-up Dodge Caravan. She said that she used to take her four children to the movies four or five times a month. But with the cost of gas, tickets, popcorn and soda adding up to $70, they now go only once a month.Still, things are not quite as bad as during the 1970s and 1980s oil shocks. In the early 1980s, at the height of the last energy crisis, energy accounted for more than 8 percent of household spending. As prices fell and the economy became less energy intensive, energy costs fell under 4 percent of household spending in the early 1990s.

With the run-up in prices in recent years, economists say energy’s share of disposable income is slowly creeping up again. Last December, that figure reached 6.1 percent, the highest level since 1985. The increase of two percentage points  amounting to $200 billion  is a huge sum, a little less than half what Americans spend each year on new cars and automobile parts.

“You’re adding an oil shock on top of a crunch on credit and a housing collapse,” said Nigel Gault, an economist at Global Insight. “Even the U.S. economy cannot withstand all of that at the same time.”

American consumers have responded belatedly by cutting back on their energy use. Oil demand in the United States grew by just 0.4 percent in 2007 and is expected to be flat in 2008.

But global oil demand, the relentless driver behind higher prices, is still expected to increase by 1.4 million barrels a day this year, analysts estimate. That growth, from China and the Middle East, may help keep prices up, whatever happens to the American economy.

According to the Energy Department’s latest forecast, gasoline prices should peak near $3.40 a gallon this spring. That figure would match the inflation-adjusted record price for gasoline that was reached in early 1981.

But many outside analysts consider the government’s forecast conservative, foreseeing a sharper spike as refiners come out of the seasonal maintenance period and start producing summer-grade gasoline in March and April.