In a document published in May 2014 that appears to have publicly surfaced last week, the Federal Highway Administration reined in its long-term forecast for driving growth in the United States, estimating that driving will increase at less than half the rate at which it has grown during the past 30 years.
The miles that vehicles in the country cover, collectively known as "vehicle miles traveled," or VMT, will grow by 1.04 and 0.75 percent per year under moderate economic growth during the next 20 and 30 years, respectively, the forecast estimated.
"This represents a significant slowdown from the growth in total VMT experienced over the past 30 years, which averaged 2.08 percent annually, although growth in motor vehicle travel was already slowing throughout most of that period," the report reads.
The document represents a sharp break from previous estimates that driving growth in the United States would continue to steadily increase at its historical pace and along with economic expansion.
About every two years, the Department of Transportation, in conjunction with the Federal Highway Administration (FHWA) and the Federal Transit Administration, issues a report to Congress assessing the conditions and performance of the nation’s transportation infrastructure — highway systems, bridges and public transit services. In the latest report, released in 2013, the DOT forecast VMT would rise 1.85 percent annually, which was the same forecast the agency made in its 2010 version.
But, according to FHWA statistics, the nationwide VMT figure has remained roughly flat for the past seven years — coming down from its peak in 2007 of 3.05 trillion miles to 2.97 trillion in 2012. That figure has not broken the 3-trillion-mile threshold since, according to FHWA and the latest information available from the Federal Reserve Bank of St. Louis.
Since 1998, it appears the DOT has overestimated how much Americans will drive in coming years, a concern for critics who say government transportation spending on federal and local levels should reflect consumer demand.
"During the period 1998-2008, VMT in the United States increased at an average annual rate of 1.23 percent, which is 0.62 percentage points lower than the baseline forecast," the 2010 conditions and performance report reads. In 2008 and 2009, VMT shrank and, comparing 2009 with 2010, VMT increased just 0.31 percent.
Data supporting rosy growth reports shrink
In its 2013 report to Congress, the DOT notes that "annual VMT growth rate has not exceeded 1 percent any year since 2004." The still more explicit report on the slowdown released last May was issued without a press release. "FHWA has no comment on it. We let the report and the data therein speak for themselves," explained Doug Hecox, a spokesman for FHWA.
The DOT is not the only federal government entity to perform an about-face on driving growth predictions. The U.S. Energy Information Administration, the statistical wing of the Department of Energy, publishes the Annual Energy Outlook and, for the 2014 copy, revised its VMT projections for the coming decades. The EIA pulled its estimate back from 1.2 percent yearly growth from 2012 to 2040, the projection made in its 2013 report, to 0.9 percent annual growth over the same time period in its 2014 version.
Addressing the trend, the administration cited "changes in driving behavior that are related to age and gender demographics. Older drivers increase as a proportion of the U.S. driving population, with their higher licensing rates but lower-than-average mileage per capita contributing to a gradual increase in total VMT."
Phineas Baxandall, a senior policy analyst on tax, budget and transportation issues at the U.S. Public Interest Research Group, a policy analysis and nonprofit advocacy network, said a variety of economic and social effects are leading to less driving in America. "There’s no one thing," he said. "Part of it’s demographics, the exiting of the baby boomer."
The slowing of suburban sprawl, which largely began as Americans left cities’ cores following World War II, and less driving demand from the millennial generation have contributed to the decline, said Baxandall, who recently found the FHWA forecast while searching DOT websites.
Traditional notions left by the wayside
The decrease in VMT, or at least its plateau, runs against a traditional notion that an expanding economy would always spur more driving. "Perpetual increases in driving is not some sort of law of nature," Baxandall said.
The decline in driving demand also coincides with an era when inner cities are safer than they once were, said Eric Sundquist, the managing director of the State Smart Transportation Initiative, an organization that works with state departments of transportation on policy issues.
"Look at the crime rates. Crime rate in cities has just fallen precipitously," Sundquist said. "That’s really turned around. Lots of cities are either reforming or relaxing."
Movement from real estate developers and zoning boards across the country to increasingly plan multi-use urban building projects has drawn more people back into cities, he said.
"That estimate is what underlies their projections for what funding is needed across the country," Beth Osborne, who worked at the DOT as the acting assistant secretary for transportation policy and the deputy assistant secretary for transportation policy beginning in 2009, said of FHWA’s new forecast.
"They released it without a lot of fanfare, and I don’t know whether that was strategic or not," Osborne said of the forecast, which is dated May 22, 2014. "So this is a pretty big deal."
Accurately predicting shifting demographics and economic and social trends is challenging, particularly in a changing economy, Osborne said. Now working for Transportation for America, a public and private advocacy organization, she left DOT in March 2014. But, Osborne said, FHWA is very "conservative" and "serious" about the reports it releases.
Just as gross domestic product is a term economists use to broadly gauge economics, VMT encompasses a wide range of transportation trends. And it appears federal agencies are moving to recalibrate how they account for Americans’ patterns on the road.
On May 12 of last year — a little over a week before it released the forecast that marked the change in its VMT forecast pattern — FHWA issued new guidance on how the administration models future driving growth.
The EIA has also employed a new approach to vehicle miles traveled among light-duty vehicles based on age groups and the aging driving population, "which resulted in a significantly lower level of VMT growth after 2018" compared with the 2013 version. Changing demographics, fewer licensed drivers, travel patterns among young age groups, and ride-sharing services like Uber and Lyft are driving the trend, the EIA said.
When collecting data to generate driving growth estimates for "Conditions and Performance" reports, FHWA has historically used the Highway Performance Monitoring System — a network that tracks data on highway operation, physical characteristics and performance — to estimate VMT. The process relies on data from the states.
Political reasons for ‘wrongness’?
Osborne said that, when she worked at the DOT, driving projections submitted from states’ transportation departments were largely unrelated to the nation’s economic health, spikes or troughs in gas prices, GDP, or employment levels. "Their estimate wasn’t [changing]," she said.
"They collected information from the states, which said we project our VMT to be ‘X,’" said Osborne, referring to analysts within DOT. "All of that was reliant on the quality of the information they got from the states."
And even though state departments of transportation would consistently overestimate driving growth during her tenure at DOT, Osborne added, "the states didn’t seem to be deterred by that."
From 1998 to 2003, per-capita VMT decreased in only nine states. But, comparing trends from 2006 to 2011, per-capita driving decreased in all but five states — Alabama, Indiana, Nevada, North Dakota and Ohio. And, according to the Bureau of Transportation Statistics, total and per-capita VMT dropped from 2007 to 2012; per-capita driving fell in all but six states — Alabama, Indiana, Montana, Nevada, North Dakota and Ohio — while VMT nationwide fell about 2 percent from 2007 to 2012.
Driving growth has consistently slowed during the five recessions since the 1970s, preceding the financial panic of 2007. Though VMT always rebounded after those contractions, the Great Recession appears to have impacted driving differently.
According to data from the Federal Reserve Bank of St. Louis, vehicle miles traveled sharply dipped in 2007 as the financial crisis mired the economy. Recessions push consumers to cut back on personal expenses, such as gasoline, insurance and all the other costs that underpin car ownership, but the statistics from the Fed, DOT and EIA indicate VMT has remained at pre-recession levels despite economic improvement.
"We have, for years, believed that rising VMT is a sign of economic growth," Osborne said. While she said FHWA needs to improve the way it forecasts driving expansion, Osborne also applauded FHWA for addressing the problem of overestimating VMT. "I’m really impressed that they got this as quickly as they did," she said. "They’re really trying to catch up with the trends."
For the heavy construction industry or politicians who want to spearhead highway projects, fewer citizens behind the wheel may spell financial distress. On Capitol Hill, VMT can be a politically charged term.
"There are political reasons why their wrongness has been advantageous for industry," said Osborne, alluding to how increased spending on transportation infrastructure by the federal government can benefit construction firms and building trade groups. "It’s a reasonably sensitive issue," she added of VMT.