This is the first article in a series about the past, present, and future of commuting in America.

In small pockets of large cities around America, a growing number of people have been walking, biking, or taking public transit to work in recent years. A disproportionate focus on these cities has led advocates and journalists to celebrate the resurgence of car-free forms of transportation.

But the researchers who study overall commuting data see things very differently. "The dominant mode of travel, by far, is the single-occupant automobile," says Alan Pisarski, a co-author of the latest Commuting in America report, which has been published over the past year. And the car shows no signs of going away.

Indeed, the percentage of Americans who commute by driving alone has actually risen since 2000 (largely at the expense of carpooling). That's largely because more and more households can afford cars, and the vast majority of people who do own a car are using it to drive to work — by themselves whenever possible:

In all, more than three-quarters of American workers now drive to work alone, while another 10 percent still ride in carpools. The number of people biking or taking public transportation might be rising very slightly, but combined they still only account for about 5.5 percent of commuters.

Driving to work alone keeps getting more common

During the 1970s, '80s, and '90s, three big trends drove changes in commuting, says Steve Polzin, a co-author of the commuting report. The sheer number of commuters was growing (due to the flood of baby boomers and women entering the workforce). More people owned automobiles. And suburbanization was growing.

The fact that more and more people were living in the suburbs meant that for a growing fraction of people, there was only one practical way to get to work — a car. Furthering this trend, governments were investing a lot in highways and relatively little in public transportation.

Originally, a large number of these commuters carpooled to work. But that has declined since the 1980s in favor of driving alone:

Danielle Kurtzleben wrote a great article for Vox on the decline of carpooling, citing a few factors here: the shrinking number of people in each household, as well as the growing number of cars (partly due to cheaper cars and greater gas efficiency).

In 1970, the average household had 1.55 cars. In 2013, it had 2.08. And the number of cars a person owns is the best predictor of the likelihood of driving alone to work.

Car ownership among low-income households keeps going up

Meanwhile, in recent decades, the number of people owning a car has kept rising — as barriers to ownership keep falling.

"When I was starting out, you could forecast a household's odds of automobile ownership based solely on income," Pisarski says. "Today, income almost doesn't matter."

There's still a gap between lower- and higher-income households in car ownership, he notes, but it's shrinking. Similarly, the gap between white households and African-American or Hispanic ones is also narrowing over time.

Meanwhile, the number of miles driven by women is getting closer to that of men. We still haven't reached total parity in any of these areas, but Pisarski speculates that we might by 2025 or so. "This is a huge shift that we haven't really appreciated," he says.

One of the big factors behind this trend has been the decreasing cost of auto ownership. Due to technological advances, cars last much longer than they used to: the average age of a car on the road has risen from 6.6 years in 1977 to 9.4 years in 2010.

This means auto ownership is more accessible to lower-income households. While they still own fewer cars — and walk, bike, or take transit to work in much higher numbers — their commuting habits are becoming more and more similar to wealthier workers'.

Biking and transit get a lot of attention — but are still a tiny share

Over the past few years, we have seen other modes of commuting finally stop declining — and, in some cases, rise very slightly.

Here's the net change in thousands of workers using each mode between 2000 and 2010. Note that the number of people biking and walking to work (or working from home) has been rising:

Most of this data comes from the US Census, which is why it stops at 2010. There's a chance that the increases in biking and public transport have been a bit more pronounced in the years after 2010, though other reports, with data through 2012, don't show it:

So what's behind the slight rise in walking and biking to work?

The pessimistic view is that walking and biking to work have essentially bottomed out. In other words, they've been declining so much in recent decades that they can't decline any longer.

An alternate view is that the slight increases are partly driven by the changing preferences of young people now entering the workforce, who theoretically prefer living in cities, rather than suburbs, and commuting by modes other than cars.

This latter idea has gotten a lot of hype in recent years, though some experts are still skeptical — and say the shifts are just the result of the recession, which left young people with less money to spend on cars. In the next article in this series, we take a closer look at the debate.