The only thing everyone agrees on about Millennial driving habits is that they're on the decline. As you'll see in the chart below, every American age group drove less in 2009 than in 2001, but the gaps were strikingly high in the 20- to 40-year-old segments of the population. There's no arguing with these numbers:
Where things get polarized is why these shifts have occurred, because answering that question would help predict how these patterns will hold up in the future—and thus what policies we should adopt in the present. So we see cities claiming victory over Millennials. And we see suburbs making similarly compelling cases. We see claims that technology is changing Millennial behavior. And counter-claims that economics are at the root of this shift. It's a tug-of-war for America's young adults.
Here's the thing: it's very unlikely any single factor will emerge as the overriding reason why Millennials aren't driving as much as their parents did. Life just isn't that clean. To that end, Steven Polzin of the Center for Urban Transportation Research at the University of South Florida and colleagues do the debate a huge service with an objective data dive into the 10 biggest factors changing Millennial driving behavior, based on a 2009 national travel survey. Let's follow them inside the numbers:
1. Place of residence. Cities and suburbs each lay claim on Millennial living preferences, but as both places become more friendly to alternative travel modes, a more telling divide may come between metro and rural areas. The share of 18- to 30-year-olds in cities today is pretty close to what it was for Boomers: 32 to 28 percent, respectively, according to Polzin and company. But for towns and rural areas the share today is 14 percent, compared with 26 percent for Boomers. Given how much more driving occurs in non-metro areas, the shift into metros alone likely explains much of the overall decline.
2. Race/ethnicity. White Americans tend to drive more than other races and ethnicities do. But Millennials appear to be more diverse along these lines than young adults were in previous generations. There were 10 million fewer whites aged 20-to-39 in 2009 than in 1990, according to Polzin's team—a 16 percent change. If that diversity continues to grow, driving habits might continue to drop.
3. Education. Millennials are very well-educated, especially compared with Baby Boomers, and well-educated people tend to drive more than those who aren't. As 20- to 39-year-olds complete their education and enter the work force—assuming they can enter the work force—vehicle mileage among this group might increase. Of course, that also assumes they can pay down their enormous student loan debts and still have money left over for a home or a car.
4. Income. Money is certainly a huge factor in Millennial driving patterns. That's largely because people who make more tend to drive more, and right now Millennials just aren't making very much. What's very striking about the per-capita figures collected by Polzin et al, is that Millennials making a lot of money don't seem to be driving much more than those making very little. The over $100,000 category is the same as the $50-54,000 range, which isn't much higher than the $30-34,000 (i.e. intern) range. That said, the very low end of the scale shows a clear drop-off.
5. Living arrangements. Traditionally, personal driving patterns have been heavily influenced by living arrangements. People who own single-family homes unsurprisingly drive a lot more than people who rent apartments, Millennials included. With lots of Millennials beginning their adult life in their parents' homes—this described about 36 percent of 18- to 31-year-olds in 2012, compared with 32 percent in 1968—where they go next will have a lot to say about how much they drive.
6. Lifecycle delay. People are marrying later in life: between 1970 and 2012, according to Polzin and company, age at marriage increased from about 23 to 29 for men and nearly 21 to 27 for women. Meanwhile, a woman's age at the time she had her first child increased from 21 to nearly 26 over the same period. Yet two-person households drive more than solos do across the board, especially when they have a young child, and these patterns are holding up for Millennials, as the figures below show. The big question is not so much whether the solos in these cohorts will drive more once they start families, but whether they'll start traditional families at all.
7. Licenses. Graduate license programs, paired with many of the economic factors mentioned above, have led to a decline in the share of licensed drivers under age 35—down from 46 percent in 1981 to 30 percent in 2012. Even if these Millennials get a license eventually, the question again becomes whether their non-driving habits will carry over into later years as a lifestyle preference.
8. Car-ownership. Whether or not you have a car has an enormous impact on how much you drive, even among Millennials, as the figures below show. At the same time, many of the economic and life-cycle factors mentioned above will make it either more difficult or less necessary for young people to make that purchase—something that has auto-makers scrambling to figure out a more attractive way to market to Millennials (i.e., the dashboard selfie). If nothing else, write Polzin et al, Millennials seem less infatuated with cars as status symbols than Boomers were.
9. Environmental values. While it's often presumed that Millennials have more respect for the environment than previous generations did, and thus a motivation to find cleaner ways of travel, that's not entirely clear in the population data. Pew surveys have shown that Millennials are actually less likely to consider themselves environmentalists, compared to other age segments. Then again, it's possible to interpret these figures to mean Millennials take environmental awareness as a given that need not be expressed.
10. Technology. It's been said (and challenged) that one reason Millennials don't drive as much is that they connect through technology rather than geography. No one doubts that technology is a native language for Millennials. The problem for transport predictions is that technology can just as easily expand car travel (think: the ease of using Uber to meet up with a friend, or the ease of ordering a delivery) as replace it.
What exactly all these factors will mean for Millennial driving habits is still anyone's guess. The charts show pretty clearly that when Millennials live like previous generations did, they drive like older Americans do. What they can't show is whether young people are merely delaying traditional lifestyles or actively changing them. Economics will certainly have a lot to do with that trajectory, but so will the strength of habits being established early on in life—something that's much harder to quantify. For now, anyone offering more certainty on the situation ahead is likely looking into the numbers and seeing not a clear future projection but their own present beliefs.