After more than 50 years of steady increases, driving in America is now on the decline.

According to a study released this spring by the U.S. Public Interest Research Group and a follow up state-by-state study released this August, miles driven per person peaked in 2004 and fell by 7.4% by the end of 2012. We are driving no more miles per person than we did in 1995. Vehicle ownership and driver licensing, other indicators of how much we drive, have also declined.

But the reasons behind the change aren’t yet clear, prompting a media frenzy over the possibilities. Does it mean the end of our national love affair with the automobile and the demise of American car culture? Are we too caught up in digital technology to bother with driving cars anymore? Or are graduated licensing requirements deterring teens from seeking a license?

While no single reason can fully explain the decline, these four factors have been identified as major contributors to the trend.

1. The Recession

When researchers first started to notice the driving decline, many thought that it was a direct result of the recent economic recession, since driving levels have been closely tied to economic activity and employment levels historically.

As shown in the graph below, the decline in driving during four other recent recessions is only a brief interruption of the overall increase in driving seen before and after each recession.

Image by Joe Cortright at CEOs for Cities, via USA.STREETSBLOG.ORG

But this recession is different. Miles driven per person peaked in 2004, and were already declining by the time the recession hit in 2007. Even though the recession officially ended in 2009 and our population is growing, driving rates continue to decline today. This indicates that the economy may not be the main cause of the decline.

In their state-by-state study, U.S. PIRG researchers expected to find the biggest driving reductions in states hit the hardest during the recession. But the study found virtually no relationship between how much unemployment increased and how much driving declined, again suggesting that the economy is only one of many factors contributing to the decline.

So, where else can we look for answers?

2. High Gas Prices Increasing the Cost of Driving

The average price of gasoline doubled between 2002 and 2011, increasing the cost of driving dramatically.

In the short term, this can cause drivers to postpone car trips in the hopes that gas might be cheaper later on. But as time goes by with no relief, drivers start to make long term changes, reorienting their lives to avoid the expense of driving by using other forms of transportation or moving closer to where they work.

While gas prices are expected to remain high in the future, this may become less important to driving trends as fuel efficiency improves and alternative fuel vehicles become more common.

3. An Aging Population

Americans in their prime career and child-rearing years, usually from about ages 35 to 54, have historically driven the most. The passage of the Baby Boom generation through this peak driving age group helped to fuel the growth of driving.

Older and younger Americans, however, are less likely to drive. As the Baby Boom generation heads toward retirement, the proportion of older Americans, who tend to drive less, is expected to increase dramatically, up from 11% of the population in 1980 to 21% by 2040.

4. Millennials Are Driving Less than Previous Generations

The generation born between 1983 and 2000, commonly referred to as the Millennial generation, will be the largest group in the peak driving age group by 2030. Their preferences are expected to have a huge effect on future transportation trends.

So far, it appears that the Millennials are even less inclined to drive than previous generations. Miles driven by 16 to 34 year olds have decreased more than the decline seen in the general population, with a drop of 23% from 2001 to 2009. The percentage of young Americans with a drivers license peaked in the early 1980s and has been dropping steadily ever since.

Economic factors, such as increased student loan debt and high unemployment among today’s young people, may explain some of the decline. However, even among young people with jobs, driving still fell by 16% from 2001 to 2009.

Some of the decline may stem from a difference in lifestyle preferences between Millennials and older Americans. More Millennials express wanting to live in walkable urban neighborhoods rather than suburbs, and report trying to make a conscious effort to replace driving with alternative forms of transportation. Millennials also rate computers and mobile devices over cars as the most important technology in their lives, and are less likely to express interest in automobiles as a hobby.

Graduated drivers licensing laws, implemented in all 50 states over the past two decades, have also been suggested as a possible reason for the decline. For more information about how the new requirements, costs, and restrictions have affected young drivers, look for our next post over at OnlineDriversEd.com.

What Can We Expect for the Future?

There is still much to learn about the causes behind the driving decrease, but so far it looks like the downward trend may be here to stay. How will the decline affect driving in the United States during the coming decades?

We’ll explore this question in our next post!