Road-trip politeness is a must, you big pain

Good choices, it's hoped. Bad choices on a road trip include lengthy cellphone conversations, messy or smelly food and failing to share snacks or treats. Swan also suggests that everybody begin the trip bathed (but not wearing strong perfume or cologne) and wearing clean clothes. It may sound a bit touchy-feely, but it's really all about caring and sharing. And that includes the driving. Sharing the driving is about manners, of course, but it's also a safety issue, says Bill Van Tassel, national manager of driver training operations for AAA.

"Everyone who has a license ought to be willing to drive and share fuel costs," Van Tassel said.

"You need to make sure you don't have a single driver going too long. I know of families who have been killed because they wanted to drive through the night and no one stayed awake." Groups on a road trip should switch drivers every 100 miles or two hours, he said. After that, as driver fatigue increases, so does risk.

At least two people should always be awake: the one who drives and the one who rides shotgun, navigating and serving as a second set of eyes.

Carolina Rosero, 24, a teacher in Guatemala, refined her system last year. After weekend road trips around Central America with coworkers, the group knew it would have to reach certain compromises.

As a group, they decided their top three sightseeing priorities. After they checked off those places, each traveler got one veto per trip.

"This means that when we decided to go see the millionth church or the 80th ruin, we could veto it if we felt grumpy, strongly opposed to it or just didn't feel like doing it," Rosero said.

"We could veto music we didn't want to hear too."

On most trips, Rosero said, everyone came to terms about sites, music, food and hotels, and everyone learned that things always went better if they discussed options beforehand.

But the first step on this long road, Swan reminds travelers, is to make sure you can, from the outset, travel safely with these people -- and keep your sanity.

"If you're the sort of person who likes to tell dirty jokes," Swan says, "don't travel with a car full of nuns."

travel@latimes.com