WASHINGTON —  The number of Americans driving and flying over the Memorial Day holiday weekend is expected to rise only slightly this year as consumers respond to the rising cost of airfares, hotel rooms and motor fuel, according to travel agency AAA.

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AAA said 37.6 million Americans will travel 50 miles or more, or about 1 percent more than last year — an estimate derived from a national phone survey of 1,500 adults. More than 80 percent of those travelers will take road trips, while another 10 percent will fly. The remainder will be packed into trains and buses.

For people traveling by rail on the East Coast this weekend, Amtrak says train service should be in good shape.

It says the cause of the power outage on Thursday that led to long delays along the Atlantic seaboard is still under investigation. Thousands of commuters were stranded during the morning rush hour when a cascading power outage on Amtrak equipment shut down service between New York and Washington.

The number of Memorial Day travelers had risen by more than 2 percent in each of the past two years, after remaining flat in 2003 and declining marginally in 2002.

The average retail price of gasoline is $2.93 a gallon, or 36 percent higher than a year ago, and that appears to be having some impact on fuel consumption, according to Energy Department statistics.

AAA forecast that flights over the holiday weekend would be about 10 percent more expensive than a year ago and that hotel rates would be roughly 5 percent higher. More than 40 percent of those surveyed said they would be staying with friends or relatives, with another 35 percent sleeping at hotels and motels.

AAA said the largest rate increase will be in the rental car segment, with prices roughly 20 percent higher than a year ago.

The price of "everything is up. But people are just going to travel," said AAA vice president Sandra Hughes. "It's not that much more than they would have spent otherwise."

For people driving on Texas highways, they may get where they're going faster than before. The speed limit is now up to 80 miles per hour, the nation's highest.