In childhood and parenthood alike, road trips mean quality time in the back seat, punctuated by theme and national parks, car games, and extended bouts of complaining. But in the giddy interim, starting the moment the car keys get handed over in high school, the road trip becomes a symbol of freedom.
''There's something liberating about not knowing where you are going, or when you're going to come back," says 18-year-old Michelle Marshalian, a sophomore at UCLA whose road trip itinerary this summer spans Mexico, New Orleans, and New York. ''After college, it will be harder to collect your closest friends and take an adventure together."
Marshalian is one of countless college students conquering the continent this summer, one highway at a time.
Marie Lee, 22, will follow her graduation from Tufts with a cross-country drive to Los Angeles. She hopes to get a job in the film industry, but for now, the city stops along the way to visit friends are her only plans.
''Everyone I've talked to is jealous that I'm going on the road trip," she reports. ''My mom wanted to come with me." She pauses. ''I said no."
The timing for this kind of open-ended odyssey is key. College often yields a new network of friends around the country. All of this takes place in a window in life where time still feels plentiful.
''For most people, as they get farther out of college, money becomes more available as time becomes scarcer," says three-time Let's Go editor and researcher Matthew Hudson, 23. ''A road trip really requires time more than money."
Hudson should know. He and Tabitha George are part of the team researching Let's Go's new book, ''Roadtrip America: The Complete Coast-to-Coast Guide to the USA." They've been chronicling their 90-day Mexico City to Anchorage trip at http://roadtrip.letsgo.com.
In another high-profile road trip, three groups of three college students each will hit the road accompanied by camera crews, armed with a mission to interview luminaries about their career paths for this year's installment of the documentary series ''Road Trip Nation."
The project kicks into full gear this month with the airing of last year's trip on PBS, a book, and a new website for college roadtrippers everywhere, www.roadtripnation.com.
Erica Cerulo, 21, who will complete the project's Southern route this summer with two University of Chicago classmates, says the program takes to the open road to provide career direction for college students.
''It's about discovering yourself and your individual route," Cerulo says.
For everyone else, the youthful trip has kept up with the times. Some iPod MP3 libraries and burned mix CDs provide the soundtrack, and the Internet eases planning, but the Jack Kerouac-style romance of the road is unchanged.
''It's perpetual choice. There's no one road less traveled, there's an infinite number that just branch off," says Hudson. ''You move through such ecological, cultural, and political diversity, and only the road itself is constant. You begin to understand these places as being a continuum with one another."
North America's vastness is seemingly made for long drives. Still, many of the Northeastern college students interviewed confessed to greater familiarity with Western Europe than with what lies between America's coasts.
For Michael Torsiello, 23, a first-year graduate student at Tufts, helping his friend and recent Tufts graduate Adrian Pellereau, 21, move to Los Angeles from Boston by car was an education in America.
''There were a lot of 'Jesus Saves' billboards along the way, so we got to talking about politics and religion a lot," says Torsiello, a New Jersey native.
Pellereau hails from Zurich, and the two were united in wonder at cross-country America. As Torsiello puts it, ''If he drove 40 hours any direction in Switzerland, he'd probably be in a different continent."
Misha Leybovich just turned 21, and in a slightly more daring take on the road trip, he's looking for a motorcycle.
''I should do it when I'm young and stupid rather than when I'm old and responsible," says Leybovich, an engineering student at the University of California at Berkeley.
Still, the jaunts around California and to Las Vegas won't necessarily be solitary.
''I might take a buddy," he says.
Hours along the highway are a way for friends new and old to get close -- or to get on each other's nerves.
''I'm sure there will be catfights," says Marshalian of her ladies-only trip. ''Shove five girls in a car for a couple weeks and there's no guarantee but catfights."
Best friends and Virginia Beach natives Andrew Flowers and James Adler are setting out with cameras and a national park pass for a multi-state Southwest tour. Having just graduated from high school, Flowers says that for him, the trip is ''a little liberation."
Adler, a sophomore at the College of William and Mary in Williamsburg, Va., was granted university funding for a photography project, and a local church also chipped in. Flowers says the two will be frugal, camping under the open sky when they aren't staying with friends or relatives.
Thriftiness doesn't always entail sticking too closely to the rules. Experienced roadtripper Brian Rozelle of UC-Davis describes how he and friends have gotten their money's worth out of hotel rooms: ''People can sleep on the ground, or get a sleeping bag and hit the bathtub," he says.
Being flexible sometimes has nothing to do with cost. On one memorable trip that found Rozelle and his friends sleeping in their car, a friend's snoring became unbearable.
''Another friend got fed up," says Rozelle, so he took his sleeping bag to snooze, somewhat precariously, atop the sedan instead. It was quieter up there, and he was that much closer to the sky.
Irin Carmon, a student at Harvard University, is a researcher-writer for ''Let's Go Travel Guides." Taking Off, her column on student travel, appears every month. She can be reached through www.irincarmon.com.