With gas prices averaging nearly $4 a gallon at the pump, thousands of Americans planning on hitting the road over the Memorial Day weekend may be forced to rethink their travel plans.

Americans are now paying an average of $3.79 for a gallon of regular gas — up slightly from last month's price of $3.47, according to a daily gas price index produced by AAA and the Oil Price Information Service. A year ago, drivers were paying $3.18.

In some parts of the country, like California, prices have exceeded $4 a gallon. In Alaska and Connecticut, prices average just above $4 a gallon statewide.

Cities like Chicago and New York City have hit new all-time highs, averaging slightly over $4 a gallon, according to Gasbuddy.com, a website that tracks national gas station prices. Some of the cheapest gas can be found in Arizona at $3.58 per gallon and Missouri at $3.59 per gallon.

Analysts say pain at the pump is likely to reduce the number of travelers taking to the nation's highways. AAA estimates that close to 37.9 million Americans will travel 50 miles or more from home, down by 360,000 travelers.

“What we have seen is that historically when the gas prices hit really high levels, some Americans will attempt to compensate in other ways,” said AAA spokesman Troy Green.

“First, they’ll travel closer to home. What we’re seeing this year is that 4 out of 10 will travel 250 miles round trip or less this holiday weekend. The average travel distance will be 640 miles round trip. Besides traveling closer to home, some people will also compensate by staying at less expensive hotels and dine at fast food restaurants.”

But Mike Lynch, president of Strategic Energy & Economic Research Inc. in Winchester, Mass., thinks there may be an end in sight. He said national gas prices will peak around $3.85 to $3.90 a gallon just before the Memorial Day weekend.

"I don't think we'll go much higher than that," he said.

As the price for gas climbs, the demand continues to slide. Many analysts think American consumers' declining appetite for fuel will eventually pull prices down. However, that theory could prove wrong if the price of oil continues to climb.

On Friday, the investment bank Goldman Sachs hiked its oil price forecast for the second half of the year to $141 a barrel.

"If we don't get a break in crude oil prices ... I can't imagine that we're going to see any relief at the pump this summer," said Stephen Schork, an analyst and trader in Villanova, Pa.

Click here to view the AAA index.

Click here for gas prices in your area.

The Associated Press contributed to this report.