The graph above shows how much Americans are driving. Because there’s a very strong seasonal pattern, which spikes in the summer, we use this 12-month “moving” series to achieve a smoother line. (Just one of the many options in FRED that helps you choose how to display the data!) We see that mileage has steadily increased over the years, with three exceptions in this sample period: Two were the massive gas price hikes—in the 1970s and 1980s—and the third is the aftermath of the Great Recession. In fact, never has a driving slump been as long and pronounced as this recent one. Does this indicate that something has changed?
The second graph looks at the same series, but this time it’s divided by a measure of population. Now we can see that yearly miles per person peaked around June 2005 at about 13,200 and then dipped all the way down to about 12,000 in March 2014. As of August 2018, it’s a bit higher, at almost 12,500 miles. But it’s been leaning downward again and may decrease even further. Are we seeing a change in commuting and traveling habits? As always, FRED will keep compiling the data so you can stay up to speed on these trends.
How these graphs were created: For the first, search for “miles traveled,” select the moving 12-month series, and click “Add to Graph.” For the second, take the first and go to the “Edit Graph” panel: Search for and add the “civilian population” series, and then apply formula a/b*1000. (Multiplying by 1000 achieves the correct units.)
How many miles do Americans drive each month, each year, over the past 10 years…? FRED has the answers. The red line on the graph is a monthly series of miles driven. As you can see, it varies greatly according to the seasons of the year, which should surprise no one. One can clearly see the upward trend, but all the jaggedness makes it more difficult to see what’s been happening for the past 10 years or so. Has there been a recent decline?
To investigate, we can use a 12-month moving average of sorts that can be created in FRED. (This graph appears below the first one.) While some moving averages include about 6 months before and 6 months after a point in time, this moving average takes the average of the 12 preceding months, which smooths the series to make it more readable. In addition, this average is divided by the civilian noninstitutional population—that is, likely drivers. (The same result would be achieved if those below age 16 were removed from the overall data.) This second depiction makes it much clearer that, per capita, Americans are driving less these days.
How this graph was created: Search for “Vehicle Miles Traveled,” then add the data series “Moving 12-Month Total Vehicle Miles Traveled.” Add yet another series, “Civilian Noninstitutional Population,” but this time select the option to modify existing data series 2. For series 2, select right y-axis position and create the data transformation “a/b.”
