While two-thirds of American families say they haven't yet scaled back their summer vacations because of higher gas prices, the other one-third are significantly changing their travel plans, The Conference Board reports today in a special survey.

Among families who are changing plans because of the run-up in gas prices, 63 percent say they will be staying closer to home, about 26 percent say they have postponed or shortened their vacations this year, and about the same number say they are canceling vacation plans because of high gas prices. The survey covers 5,000 U.S. households and was conducted for The Conference Board by TNS in July. The survey was conducted before news reports announced an alleged plot to blow up aircraft en route to the U.S. from London.

"These survey results show that while most Americans haven't changed their vacation plans because of rising gas prices, a substantial proportion -- one in three -- have been compelled to alter vacation activities. Looking ahead, the combination of high gas prices and possible fallout from the recent terrorist threat could further change Americans' travel plans."

GAS PRICES AND COMMUTING

When asked if higher gas prices have affected their commute to work, nearly one-fifth said yes. Among those who have changed their commuting routines, about 20 percent said they are doing more work from home, another 16 percent said they are car-pooling, and 10 percent are using public transportation.