ON ROUTE 66 IN NEW MEXICO — Bob Pack forgot to bring his James Taylor CDs. Still, he and his brother and sister were having a blast, rolling among the sandstone mesas, ghost towns and kitschy tourist attractions.

They reminisced about family trips as children back in the 1950s, Mr. Pack and his sister, Joann, said, and not even their brother’s “annoying” habits of chewing tobacco and telling dirty jokes could ruin the drive. “I wanted to see West Texas one more time,” he said over breakfast at the Route 66 Casino Hotel.

Over in Arizona, Kay McNellen, a 23-year-old actress from San Diego, said she took to the highway almost every weekend these days, just to see how far she could drive. She has motored across the Mojave Desert, admired Sequoia National Forest and Instagrammed the Grand Canyon. “This is a better view than Netflix will give you,” she said.

The great American road trip is back.

It’s partly that gasoline this driving season is cheaper than it has been in 11 years, according to the AAA motor club, and that the reviving economy is making people more willing to part with their money. But there is more than that at play here. This may be a cultural shift, as Americans experiment with the notion that maybe money can, in fact, buy happiness, at least in the form of adventures and memories.

It is a change that appears to have taken root in the years since the 2008 financial crisis. “Postrecession, people are focused on memories that cannot be taken away from them, as opposed to tangible goods that expire and wear out,” said Sarah Quinlan, a marketing executive at MasterCard Advisors. “There’s a sense that you can take away my job, you can take away my home, but you can’t take away my memory.”

Whatever their motivation, Americans last year drove a record 3.15 trillion miles, according to the Department of Transportation, beating the previous mark, set in 2007. So far this year, both travel and gasoline consumption are up again.

The desire to get behind the wheel still comes as something of a surprise. The conventional wisdom was that driving mileage had probably peaked in 2007. The demographic bulge represented by the baby boomers is aging out of the driving years; people typically drive less as they hit retirement.

At the same time, millennials were not sharing the passion for the open road that previous generations of young adults had. Many, in fact, preferred to live in the nation’s downtowns, eschewing personal cars in favor of shared Ubers, or walking to their work and play.

But it turns out that both generations are driving more than anyone expected. “A lot of millennial behavior was really deferred assimilation,” said Steven E. Polzin, a transportation researcher at the University of South Florida. In other words, just like Mom and Dad, they were destined for a more traditional lifestyle — the marriage, the home, the garage — they just took a little longer to get there.

One such millennial is Jenna Bivone, a 29-year-old website and app designer, who two years ago left downtown Atlanta to live on the outskirts of the city with her boyfriend. “We used to walk everywhere, but the rents were too high and we wanted some land for my dog,” she said. “In a more suburban area we found good schools, stuff like that for future plans.”

Now she has a daily commute of at least a half-hour each way, and on weekends she and her boyfriend drive around Georgia and neighboring states looking for the best hiking. Over the last three years they have taken road trips in Wyoming and Colorado to hike in the national parks.

“When we travel we want to go to places we might never see again,” she said. “We’re not going to be young forever.”

Michael McNulty, a 67-year-old biotech executive from San Francisco, might not agree with the last part of her statement. Last year he bought a used Ford Airstream B-190 motor home on Craigslist for $13,000 as an experiment. He and his wife are enjoying the road trips, he said, and they are gradually extending their radius.

“The kids’ colleges are paid for, and they are out of the house,” he said. “We have been all over the world, and now we are seeing the U.S.A.”

Mr. McNulty did all the driving to the Grand Canyon for an extended weekend in April, and he prepared to drive all the way back home, 14 hours, in one day. The reason was simple, he said. “We’re going to go for it on Tuesday,” he said, smiling, “because I have to get back to work on Wednesday.”

The phenomenon is being further amplified by, of all things, a desire in some families for cross-generational adventures that harks back to a halcyon age of bundling everyone into the station wagon, counting license tags from faraway states, and mediating back-seat fights over who started the fight. Baby boomers, it seems, want to bond with their grandchildren on the road. Rental-car companies are reporting increased demand for bigger vehicles to accommodate the generations.

Along Route 66 recently, near the parking lot of Petrified Forest National Park in Arizona, Rita Bandy, a 62-year-old widow from Philadelphia, Tenn., described having just such an experience driving cross-country with her 11-year-old grandson last summer. “He and I together, it was just so wonderful,” she said. “I never saw him so happy, laughing and joking with me.”

Ms. Bandy pointed out that she had plenty of toys at home — a pool, a motorcycle. “I have everything,” she said. “All I want now is memories with my grandchildren, and to let them see that I was fun, and not just old.”

Last year’s trip with her grandson was so great that her older sister Vicky said she was jealous and wanted to do the same thing. So this spring — along with their third sister, Gail, and two husbands, all retired — they piled into a Toyota van to take the classic American road trip, Route 66. After visiting Branson, Mo., and a cowboy museum in Oklahoma City, they stopped at the Petrified Forest on their way to California.

“I always wanted to see the Pacific Ocean — and now we’re doing it!” Ms. Bandy said just before entering the national park.

Few, perhaps, carry a sense of wanderlust as far as Anne Utech, a 36-year-old federal employee, who found herself along Route 66 one recent Friday after visiting the giant meteor crater in northern Arizona. A year ago, she gave up her Houston apartment to go on the road full time in her pearl white , which she has named Pearl. A copy of the Ralph Waldo Emerson essay “Self-Reliance” sat on the passenger seat.

“I do my best thinking while driving,” said Ms. Utech, who works from her laptop and stays with friends or at hotels or takes short-term rentals along the way. Most of all, she says, “I like to get lost, and Pearl is my best friend.”

All of this has been good news for the hotels, restaurants, theme parks and other destinations that depend on travelers’ rolling up on four wheels. Attendance at national parks last year reached 300 million for the first time. The 5.5 million who visited the Grand Canyon in 2015, for example, was a 16 percent increase from the year before, and park officials project a similar increase this year. On one recent weekend, during spring break, the car line at the south entrance was two and a half miles long, a wait that local rangers said was extremely rare.

Theme parks are also reporting strong business, with attendance up by about 2.5 percent in 2015, according to initial estimates. Industry experts project a 2.9 percent increase this year over last.

Over the long Memorial Day weekend, the AAA estimated that 34 million Americans took road trips of 50 miles or more, a 2.1 percent increase over last year and the highest number since 2005. Branson, Mo., the country music mecca, is investing $300 million in for the summer, including new indoor and outdoor adventure parks and a new Imax movie theater.

NBC Universal just opened the Wizarding World of attraction at its Hollywood theme park, which was estimated to cost $500 million, and it is just one of several recent expansions of tourist destinations in California — including Disneyland in Anaheim and Legoland California in Carlsbad. Buc-ee’s, a convenience store chain, just got approval from Katy, Tex., to build a gas station the size of a football field with 100 pumps along Interstate 10.

And then there is that ultimate symbol of the road trip, the recreational vehicle. Wholesale shipments last year reached the highest level since 2006 and appeared to be making further gains this year. Here in , an R.V. resort is being built beside the , outside Albuquerque, complete with 100 full-service parking sites (as well as two fenced-in dog parks).

Part of the driving phenomenon can be explained by the improving job market and more commuting, but far from all of it. Public transit use was down slightly last year from 2014, while every driver averaged 2.6 percent more miles on the road. Rural and highway travel was particularly up. And early indications point to an acceleration of the trends this year.

Changes like these come at an inopportune moment, given the commitment by the United States to make steep reductions in carbon emissions after the Paris climate accord last year. The fact remains that coming to terms with climate change, experts say, means people must burn less petroleum in the future. With Americans driving more miles at lower cost — and in bigger S.U.V.s, recreational vehicles and trucks — that goal is going to be harder to reach, at least in the short term.

According to Dan Sperling, director of the Institute of Transportation Studies at the University of California, Davis, most of the increased driving can be accounted for by the steep decline in prices at the pump. Gasoline prices have fallen more than 50 percent in the last two years, he said, saving the average household with two cars as much as $1,000 a year.

New models of cars and light trucks, which under federal rules must nearly double their fuel efficiency by 2025 to 54.5 miles per gallon, “will more than offset the behavioral increase of more driving,” he said. “In 10 years vehicles will be consuming half as much fuel as they do today.”

Fuel prices certainly figured in Frank Claeys’s decision to take a 10-day road trip with his wife and two sons during their spring break. They were originally just planning to drive to Utah for some backpacking. But with a gallon of gas cheaper than some candy bars these days, they decided to stretch the journey all the way to the Texas Panhandle.

“We were less tight,” said Mr. Claeys, a 40-year-old police officer from Gaylord, Mich., as his children bought ice cream and shopped for polished stones at a roadside trading post in New Mexico. “At $2 a gallon, I don’t cringe at the pump.”

Aaron Conley, the 35-year-old owner of a Cincinnati lawn landscape company, has been taking long road trips with his girlfriend, Michelle Mercer, a bartender from Burlington, Ky. This year they drove to New Orleans for Mardi Gras, then took a swing around the Gulf Coast to Port Arthur, Tex.; Lake Charles and Baton Rouge, La.; and finally the Florida Panhandle.

On a recent trip they flew to Las Vegas and then drove to the Hoover Dam; the Grand Canyon; Sedona, Ariz.; and finally Death Valley, Calif. “When gas was $4 a gallon, we didn’t travel at all,” he said, recalling the early years of the couple’s six-year relationship.

And — in one sign of how quickly things could change again — they almost didn’t make it to the Grand Canyon this spring. The reason? They discovered that prices were not quite as low as they thought. “When we saw gas was $2.25 a gallon here, that was at the tipping point,” he said of the difference between prices in northern Arizona and the $1.70 he had been seeing back home.

Ms. Mercer was quick to agree. “I’d rather not spend a lot of money on gas,” she said.