Of course road traffic is going to be horrendous this Fourth of July -- record-breaking, in fact, according to AAA.

But it's not just cars that'll be clogging the transportation byways. Up to 48 percent of travelers plan to use public transit when they travel this summer, according to the American Public Transportation Association. In a new survey -- the first ever of its kind -- the APTA found of the 90 million American adults will travel to large American cities this summer, an average of one out of three will use public transportation.

The survey also showed that travelers' use of public transportation will increase this summer. Twenty-eight percent of those who will use public transit while visiting a city said that they are more likely to use it this summer as opposed to last year.

Most of the survey respondents said they plan to use public transportation because it's cheaper that taxis and less of a hassle than driving and parking in an unfamiliar city. (Interestingly, "high gas prices" didn't rank highly as a reason for switching to public transit.)

So enjoy your Fourth of July holiday -- and, uh, maybe you should think about walking to that fireworks display?