Last year, Dave Rodham bought two Ford Mustangs — a red one because it looked cool and a white one with a big V-8 engine because it sounded cool. For Rodham, 63, those were his 50th and 51st cars.

"I have to have a new car every year and a half to two years," said Rodham, of Virginia Beach, Va., who said he pays cash for his cars. "After I retired 10 years ago, I didn't have anything else to do, so I went out and bought new cars."

For generations, car buying declined as consumers entered their golden years. Now, boomers are refusing to follow their parents' lead and go quietly into the car buying night.

The 55-to-64-year-old age group, the oldest of the boomers, has become the cohort most likely to buy a new car, according to a new study by the University of Michigan's Transportation Research Institute. Graying boomers replaced the 35-to-44-year-old age group, who were most likely to buy four years ago.

The findings show there are plenty of miles left in boomers' automotive passions and pocketbooks. They also suggest the billions the auto industry spends to try to woo the elusive Generation Y, the children of the boomers, would generate a higher return on investment if targeted at older drivers.

"You shouldn't be chasing the younger people; you should be looking at the older people," Michael Sivak, author of the study, said in an interview. "Baby boomers are trying to extend their youth as long as they can, both in terms of taking care of their bodies and in their expenditures."

And the recession is extending the working years and peak earnings period of the 76 million Americans who were born from 1946 through 1964 in a post-World War II birth boom.

"People's nest eggs were decreased, including their retirement portfolios, by the recession," said Lacey Plache, chief economist for auto researcher Edmunds.com "We can expect these people to be in the workforce longer and, as a result, buying cars longer."

There's also a strong psychological reason: Their cars define them.

"The car was a phenomenon of the 20th century," said John Wolkonowicz, a Boston-based automotive historian and a former Ford product planner. "For people who grew up and lived in the 20th century, the car was freedom, it was status, it was an extension of you, a visible expression of you and your personality. A 20-year-old doesn't see the car the same way."

Indeed, young people don't seem that interested in driving. Just 79 percent of people ages 20 to 24 had a driver's license in 2011, compared with 92 percent in 1983, according to the Michigan study.

Automakers have spent billions to produce youth vehicles, which end up selling better to boomers. A decade ago, Honda fielded the boxy Element sport-utility vehicle with clamshell doors and rubber floors that could be hosed out by on-the-go young people. Instead, boomers bought the car until it was discontinued in 2011.

"One of the dirty little secrets of the auto industry is all these cars are positioned in advertising and public relations as something a 25-year-old will buy," said John Morel, a market researcher for Honda.

"But your propensity to buy a car at 25 is roughly a quarter of what it is at age 65. By definition, very few cars sell in high volume to 20-somethings."

Toyota's Scion line aimed at Gen Y also has sputtered. Scion sales fell 9.3 percent last month after a 25 percent plunge in June and are down 1.8 percent for the year at 41,261, according to researcher Autodata. Toyota sold 73,505 Scion models last year, down more than half from a peak of about 173,000 in 2006.

But it still has a devoted follower in Michael Leek, 60, a city planner in Shakopee, Minn. He drives a "Cherry Coke" red Scion tC that he upgraded with gray pinstripes, a lowered suspension and a growling, chrome-tipped exhaust. Leek is shopping for a new Scion FR-S sports car.

"City planners ought not to like cars as much as I do and guys who are 60 should be getting over it, but I haven't," Leek said. "I look in the mirror every day and I'm pretty sure I don't look like I'm 30 or 20. That's not a problem. It's really whether I enjoy driving the car and like how it looks when I walk up to it and when I walk away from it. And I do."

Now Toyota is embracing its boomer buyers with a model targeted at them, the Venza sport wagon that's easier for aging drivers to climb into than a high-riding sport-utility vehicle.

Ford's Escape small SUV has become a boomer magnet since a redesign last year made it more carlike and less rugged-looking, said Amy Marentic, Ford marketing manager. The average age of Escape buyers this year is 52, up from 51 last year. And 45 percent of the Escape boomer buyers opt for the fully loaded Titanium package, starting at $29,100.