There is certainly not less to celebrate this July Fourth -- this is America's birthday, after all -- but there is less celebrating.

Economic uncertainty and rising prices at the pump (now at $2.67 per gallon of unleaded) are keeping more of us home-- at least closer to it -- this holiday weekend, say those in the business of tracking such things.

The American Automobile Association projects that the number of Americans traveling this holiday weekend -- an estimated 37.1 million -- is a 1.9 percent decrease from last Independence Day. It's a much bigger decline -- 10.5 percent -- if you look to 2007, when 42.3 million hit the road and skies.

A trip is defined as traveling 50 or more miles from home; for these numbers, AAA surveyed 2,700 Americans.

The AAA, whose East Central office is in East Liberty, said the projected decline was blamed on continuing uncertainty about the economy, rising joblessness and sagging personal incomes. The recent rise in gasoline prices -- up steadily since May, though significantly down from last July -- also is keeping more of us in "Porchville."

Caroline Grossman, of McKeesport, is one.

Usually the Mon Valley grandmother, her daughter, son-in-law and three teenage grandchildren make a 12-hour drive by van to Myrtle Beach, S.C., the week of the Fourth. Not this year.

"Why go and worry about money and if the price at the pump is going up while you are miles from home?" explained Mrs. Grossman.

"A vacation is supposed to be about fun and relaxing ... not counting pennies," she said.

Instead, the widowed retiree is putting together a barbecue in her back yard. "No one will be driving more than 15 miles to come," she said.

The beach now falls into the wistful category of "maybe next year," she said.

About 1.4 million Pennsylvanians will travel by car and van this holiday, which for the most part is celebrated tomorrow through Sunday. The July Fourth holiday is typically the busiest time of year for travel by auto.

"Many Americans remain cautious about the outlook for their personal finances, and these attitudes are reflected in the slight decline in travel we are forecasting for the upcoming holiday weekend," said Jim Lehman, of the local AAA. "Those who do vacation this summer will find unprecedented discounts. If you can afford it, this year is a smart time to travel."

However, air travel will increase, Mr. Lehman said. The AAA estimates that 50,000 Pennsylvanians will travel by plane this weekend.

Air travel accounts for only 5 percent of July Fourth leisure travel, but the industry expects to see a 4.9 percent increase in leisure travel bookings this holiday. Two million Americans will board airplanes.

Mr. Lehman said the increase was due to airfare bargains as well as pent-up demand from those who have not traveled recently. Last July Fourth, air travel declined steeply, so this year's rebound is significant.

According to AAA's Leisure Travel Index -- a monitor of pricing in 20 popular cities across the United States for hotel and car rentals as well as 40 pairs of cities for air travel pricing -- the lowest average published airfares over the July Fourth holiday weekend are expected to decrease 16 percent from last year.

The AAA also put together some statistics for those who do venture far from home this holiday. Note that you pay to play:

Average spending will be $1,160 per household, and transportation and accommodations will account for about half.; average distance traveled will be 614 miles.