The Johanson family gathered around a Rand McNally road atlas once every other summer for the express purpose of pinpointing the perfect route through America for their wildly anticipated summer road trip.

Their first forays into the American countryside took place in a red station wagon and the later ones in a blue minivan with wood-paneling, but what happened inside never changed. Dad drove and acted as tour guide as mom juggled her duties as navigator, snack-distributer and lunch-preparer. Dad, an unabashed fan of "shortcuts," always found the longest way to go amid the serendipity of the side road -- much to mom's dismay.  Meanwhile, the only Johanson daughter ordered her baby brother around as their brother, the middle child, bestowed a skewed (and often incorrect) knowledge of the American landscape.

The itinerary, grand as it was, never quite matched the execution. The family instead chased around North America, emulating the Japanese tour groups they saw, stopping for a quick snapshot and running so fast they barely had time to breathe. Each day, they trawled the national parks and American icons of Middle America in search of the perfect spot to take an enviable photo for the family Christmas card. But when the "are we there yet" overture reached its climax, Dad passed the kids the AAA guide and together they identified the cheapest motel with a pool and continental breakfast.  At nightfall, the family stripped off their souvenir T-shirts, played a quick travel-sized board game, penned some postcards and hit the sack so they could do it all again the next day.

If the idiosyncrasies of the Johanson family road trip sound familiar, then your childhood vacations were just like mine.

They were days of endless peanut butter-and-jelly sandwiches -- of roadside glitz and truck-stop kitsch. They were the kind of trips that taught you about history, geography and sociology before you even knew what those words really meant.

But something's happened in the past decade that's keeping many families closer to home. What it is, though, goes by many names. Some call it oil. Others call it a loss of pleasure in the roads. Researchers prefer the buzzier title "peak travel." Whatever the reason, it's got people wondering: Will extended road trips soon become so expensive, so cumbersome and old-fashioned that they wane into the realms of nostalgia?

The Rise And Fall Of The Road Trip

Without the Interstate Highway System of the late 1950s, there would be no "great American road trips." Indeed this concrete spider web, the brainchild of Dwight D. Eisenhower, allowed for the wholly American phenomenon to flourish.

Road trips emerged as a popular American pastime alongside the growth of the highways, which, by the mid-1980s, linked the contiguous states from coast to coast. For the first time, it was possible to get from New York City to San Francisco in 48 hours (nonstop) by your own means.

An entire culture of truck stops, gas stations and drive-thrus evolved around the highways, thus transforming the recreational habits of Americans. In fact, the open road became so popular that by 1962 nearly 75 percent of all public lodging establishments in the United States were roadside motels.

Though the highway may evoke riling images today, at the time it represented freedom, speed and the romantic idea of self-discovery.

"Such wide travel fulfilled an American sense of accomplishment and empowerment," said Keith A. Sculle, co-author of "Remembering Roadside America: Preserving the Recent Past as Landscape and Place."

Enshrined in American literature ("On the Road") and iconic movies ("Easy Rider"), the Interstate Highway System was seen as an extension of the American Dream, of manifest destiny and the tradition of individualism. It reshaped iconic cities, fostered the automobile industry's growth and became a symbol of youth culture and the pioneering spirit.

Yet what began as a counterculture movement evolved into something decidedly more wholesome. Family road trips, by the late 1970s and 1980s, were a staple of any middle-class upbringing. The exploration of the American landscape, it seems, gelled with the predominantly conservative ideals of the time. By the mid- to late-1990s, however, they diminished in popularity as Americans favored purpose-built vacations that were more about destination and less about journey: A quick jaunt by plane, a tight schedule and pre-arranged sights.

Then 9/11 happened and long journeys by automobile had a brief renaissance in the wake of grounded planes and newly instilled fear. Several media outlets, the New York Times most notably, became fascinated by the road trip again, by its Americana ethos.

"For years now, the pleasures of the road trip have palled," Julia Chaplin wrote in The New York Times in November, 2001. "Driving long distances became a time-guzzling burden, and Interstates seemed more often linked with road rage and bad French fries. But then came an overnight fear of air travel and a yearning for escape from new urban anxieties, especially in New York. Suddenly, the open road holds a fresh appeal for those who have single-mindedly pursued big-city lives and ambitions."

Travel + Leisure, too, stepped up its coverage of road trips that winter to meet the rise in demand, but a staggering spike in gasoline prices after 9/11 made sure the renaissance, timely as it was, remained short-lived.

Have We Reached 'Peak Travel'?

AAA, the North American motor club, collects annual statistics on four holiday travel periods and claims automobile travel hit a decade high over Independence Day this year, with approximately 35.5 million Americans on the road.

Public Relations Manager Heather Hunter said that, despite gas prices, an overwhelming majority of people (about 84 percent) choose to travel by car.

"Automobile travel can still be a much more affordable means of travel," she said. "Even when gas prices are high, it's still more reasonable."

She's right, but it's not nearly as affordable as it used to be.

The automobile agency put the average price of gasoline in July at $3.50 per gallon, down 0.44 cents from an April peak but well above the average in, say, 1989, when it was around $1 (or about $1.47 adjusted for inflation).

Let's say you wanted to take a trip from St. Louis, Mo., to the ultimate family playground of Disney World, just south of Orlando, Fla., and exactly 1,000 miles away. Riding in a 2012 minivan (which gets around 24 miles per gallon) and using the average price at the pump this summer, gas for a roundtrip journey would cost around $292.

Accounting for inflation and an average fuel economy of 21 miles per gallon, that same trip in 1989 would have cost $140, less than half as much.

AAA's assertion that more people are on the road may also be correct, but the distances they're traveling appears to be smaller. Moreover, there are signs in the United States -- along with Canada, the United Kingdom, Germany, Japan, Australia and other wealthy nations -- that driving has reached a sort of saturation point.

"Since 2003, motorized travel demand has leveled out or even declined in most of the countries studied, and travel in private vehicles has declined," Stanford University Professor Lee Schipper and doctoral candidate Adam Millard-Ball wrote in research published last year. "Car ownership has continued to rise, but these cars are being driven less."

Schipper, the former director of research for the World Resources Institute's Center for Sustainable Transport, or EMBARQ, believes high fuel prices, strict time constraints, vehicle taxes, road congestion and aging populations have all contributed to a major shift in travel patterns. He suggests that some parts of the world have reached "peak travel," an ironic take on the concept of peak oil.

"Fuel economy is improving slowly, and travel isn't increasing," Schipper said in a speech at Stanford last year.  His research with Millard-Ball shows a leveling off of both private car use and total passenger travel between 2003 and 2008, when, historically, automotive travel had increased along with rising incomes. The scholars' conclusions line up with similar research from Robert Puentes and Adie Tomer of the Brookings Institute. Both found that driving patterns, as measured by vehicle miles traveled, began to plateau in the mid-2000s. Essentially, they all agreed, we're not driving our cars as much or as far as we used to.

Pleasure vs. Necessity

So is the "great American road trip" on the decline? It's hard to think of a time when it will be any cheaper than it is today (which is to say it's already more expensive than it was yesterday).

Brian Ladd, historian and author of two books including "Autophobia: Love and Hate in the Automotive Age," says there is strong evidence from the "peak travel" researchers and others that we are at a crossroads.

"When a car becomes a necessity rather than a pleasure, that will be a turning point," he said. "We may already be there. In fact, we may even be well past that. Driving because you want to is now the exception."

But if you look at any travel guidebook for the United States, the road trip's relevance shows no sign of subsiding.

"Right up there with baseball and apple pie, taking to the highway is an American tradition," according to Fodor's "Essential USA" guide. The authors recommend the Pacific Coast Highway, the Great River Road along the Mississippi, U.S. Route 1 and Route 66 for the best slice of Americana.

However soulless highways may seem today, Fodor's and others extoll them as places that offer mystery, discovery and, perhaps, a view of the "real" America.

In his essay "Taking the Great American Roadtrip," esteemed travel writer Paul Theroux says "the visible expression of our freedom is that we are a country without roadblocks." After all, he adds, a driver's license is our identity.

But the car's identity and our relationship with it has certainly morphed over the years, Ladd argues. Anecdotal evidence, he said, suggests that the car is not as important of a possession nowadays as it was for his generation. But he doesn't believe long road trips will become a thing of the past; quite the contrary.

"It will cost more and be something families will have to think more about, but at the end of the day, the road trip may actually be less affected than other areas of automobile travel. It would be a luxury, sure, but if we move away from dependence on the car and a world in which the car is a necessary part of life, we might actually get back to where we were a few decades ago."

Back, he said, when the car trip was the ultimate pleasure.