You might think that fewer airline flights and higher air fares would mean more Americans taking road trips to the national parks.

That hasn't happened yet, although National Park Service spokesman David Barna hopes it will. Meanwhile, for those who like their parks less crowded and overrun, this could be a good year to go.

There are 391 national park properties across the country -- monuments, sea shores and historic sites, as well as the big, scenic preserves with their mountains, lakes, deserts and rock formations.

The number of visitors hit an all-time high of 287 million in the late 1990s, but after the 9/11 attacks the number dropped by almost 20 million, mostly due to a fall-off of travelers from abroad.

When the numbers bottomed out, Mr. Barna said, it wasn't the Grand Canyon, Yosemite, Yellowstone, the Grant Tetons or Acadia that took the big hits. "Their numbers actually went up," he said.

For the past four years, overall visits have held steady at 275 million. "They're going back up, but not as high as projected," he said.

Mr. Barna gave several explanations for that. Rising gas prices played a part; so did a lessening of American prestige abroad.

Also, he said, "the face of America is changing, but the parks' visitors are not." Middle-class Caucasians still make up the majority of visitors, but growing segments of the population -- Hispanic, black, Asian -- are not coming very much.

"We're trying to get into inner-city schools and interest the kids in the natural world," he said.

The parks are also low-tech at a time when many families are seeking the whiz-bang effects of the giant theme parks.

"The whole Disney thing pulled a lot of our previous visitors, and we don't have data to show we're getting them back," Mr. Barna said.

Now that gas has dropped below $2 a gallon, travelers may want to take another look at the national parks. Information is available online at www.nps.gov.