MADISON, Wis. -- AAA officials are offering a friendly warning to those planning a driving trip during this July Fourth holiday weekend: expect some company on the roads.

Officials said that they believe this will be the busiest July Fourth ever with an record 40.7 million Americans are estimated to be hitting the nation's roads.

This week also marks the 50th anniversary of President Dwight D. Eisenhower signing an act that started the interstate highway system. The project is widely credited with helping Americans get to their holiday destinations faster and safer than ever before.

Some Wisconsin Department of Transportation officials are saying that more care will be necessary as the highways get older and face increasing demand.

Rob Miller, a DOT spokesman, said that three-fourths of the interstates in Wisconsin were built between 1959 and 1969.

"Overall, the system is in shape and there are parts where we're gonna need to address congestion in the future and that will have to be looked at," Miller said.

With concerns of road congestion uppermost on her mind, Deerfield resident Kim Petrick said that she plans to leave early on her trip to Indiana.

"I have the day to get ready, get on the road and miss the bulk of traffic," Petrick said. "I'm afraid if we leave Saturday morning, we'll get stuck in Chicago construction and all that fun stuff."

The congestion that many drivers will face this weekend is caused by the amount of traffic increasing faster than the roadways could be built, officials said.

To avoid traffic, officials said that the busiest times on the roads will be Friday between 11 a.m. and 8 p.m. and again on Saturday morning. On the way home, they advise drivers watch out on Tuesday between 11 a.m. and 8 p.m.

Gas Prices Surging

Another headache that holiday travelers will have to face is higher prices at the gas pump. The prices spiked Wednesday night, just in time for holiday travel.

The average price for a gallon of gas locally is $2.97 -- almost 75 cents more than last year. Nationally, gas prices are about $2.90 a gallon.

One year ago, gas sold for $2.24 locally and $2.22 a gallon nationally, WISC-TV reported.