Changing Travel Demands: Implications for Planning

Todd Litman's picture
Blogger

The graph below shows the most recent USDOT vehicle-travel data covering the last 25 years. Although vehicle-miles of travel (VMT) grew steadily during most of the Twentieth Century, in recent years the growth rate stopped and even declined a little. It is now about 10% below where it would have been had past trends continued.

US VMT Trends

This is particularly notable because during this period both population and economic activity grew, so VMT per capita and per unit of economic activity declined. This has important implications for planners.

The Twentieth Century was the period of automobile ascendency, during which personal motor vehicles grew from virtually nothing to becoming the dominant travel mode in most developed countries. During this period it made sense to invest in automobile-oriented infrastructure: paved roads, highways and parking facilities. However, demographic and economic trends are changing travel demands. Aging population, rising fuel prices, increasing urbanization, increasing traffic congestion, improvements in alternative modes, changing consumer preferences, and increased health and environmental concerns are all reducing demand for automobile travel and increasing demands for travel by other modes. Although automobile travel will not disappear, it will not grow as it did in the past, and in many developed countries motor vehicle travel will be flat or negative in the future.

This requires a major change in the way we think about transportation problems and evaluate solutions. Most state and regional transportation plans are based on the assumption that VMT will continue to grow as it did in the past, so the primary problem is traffic congestion. The decline in VMT growth indicates that traffic congestion problems will be less severe and other problems will become more important, including inadequate mobility options for non-drivers, transit crowding, transport affordability, and environmental concerns.

This suggests that policies and projects which help create a more diverse and efficient transportation system will be the most cost effective solutions to the diverse problems communities face, while the need to expand roads and parking facilities will decline.

This is good news for transport planners and engineers, provided that your interests and skills align with these trends. Experts in pedestrian and bicycle planning, streetscaping, parking management, public transportation planning, roadway operations, smart growth/new urbanist development, efficient transport pricing, and energy efficient transport planning, to name a few related specialty areas, will have skills that communities need.

 

For more information

Dan Brand (2009), Impacts of Higher Fuel Costs, Federal Highway Administration, (www.fhwa.dot.gov); at www.fhwa.dot.gov/policy/otps/innovation/issue1/impacts.htm.

Heather Contrino and Nancy Mcguckin (2009), "Travel Demand in the Context of Growing Diversity: Considerations for Policy, Planning, and Forecasting," TR News, Transportation Research Board (www.trb.org), September-October, pp. 4-9; at http://onlinepubs.trb.org/onlinepubs/trnews/trnews264TravelDemand.pdf 

Todd Litman (2006), The Future Isn't What It Used To Be: Changing Trends And Their Implications For Transport Planning, Victoria Transport Policy Institute (www.vtpi.org); at www.vtpi.org/future.pdf; originally published as  "Changing Travel Demand: Implications for Transport Planning," ITE Journal, Vol. 76, No. 9, (www.ite.org), September, pp. 27-33.

Todd Litman (2009), Where We Want To Be: Home Location Preferences And Their Implications For Smart Growth, Victoria Transport Policy Institute (www.vtpi.org); at www.vtpi.org/sgcp.pdf 

Adam Millard-Ball and Lee Schipper (2010), Are We Reaching A Plateau Or "Peak" Travel? Trends In Passenger Transport In Six Industrialized Countries, 2010 Transportation Research Board Annual Meeting (www.trb.org); at www.stanford.edu/~adammb/Publications/Millard-Ball%20Schipper%202010%20Peak%20travel.pdf.

Arthur C. Nelson (2006), "Leadership in a New Era: Comment on "Planning Leadership in a New Era," Journal of the American Planning Association, Vol. 72, Is. 4, Dec. 2006 , pp. 393 – 409. Also see Arthur C. Nelson (2009), The New Urbanity: The Rise of a New America, University of Utah Metropolitan Research Center; summary at www.froogalizer.com/news/research-on-homeownership-rate-through-2030.html.

Robert Puentes (2008), The Road Less Traveled: An Analysis of Vehicle Miles Traveled Trends in the U.S., Brooking Institution (www.brookings.edu); at www.brookings.edu/reports/2008/1216_transportation_tomer_puentes.aspx?emc=lm&m=220694&l=17&v=39243.

Stuart Ramsey and David Hughes (2009), "The Challenge of the Oracle: Optimizing Transportation Infrastructure in a Changing World," ITE Journal, Vo. 79, No. 2 (www.ite.org), pp. 69-73. www.transportplanet.ca/WriteTheChallengeOfTheOracle.pdf.

Nate Silver (2009), "The End Of Car Culture: It's Not Just Erratic Gas Prices And A Bad Economy That's Hurting Automakers. It May Be That Americans Are Changing," Esquire (www.esquire.com); at www.esquire.com/features/data/nate-silver-car-culture-stats-0609. 

Gary Toth (2007), "Back To Basics In Transportation Planning: Rediscovering Our Roots Can Solve 21st Century Traffic Woes," Making Places Bulletin, Project for Public Spaces (www.pps.org); at www.pps.org/info/bulletin/back_to_basics_in_transportation.

USDOT (2010), Traffic Volume Trends, U.S. Department of Transportation (www.dot.gov); at www.fhwa.dot.gov/ohim/tvtw/10aprtvt/10aprtvt.pdf.

Todd Litman is the executive director of the Victoria Transport Policy Institute.

Comments

Comments

Michael Rodriguez's picture

Great Recession Effects on VMT?

Great post Mr. Litman. I wonder how much of the VMT decline might be explained by the historical uniqueness of the Great Recession as opposed to some overall change in values and perceptions about auto travel.

We know that VMT (and other forms of travel, such as airline and rail travel) are linked to economic conditions. As our economy worsened, people are less likely to travel far to take vacations; they forgo that extra trip to the outlet mall; they are more likely to stay at home than go out on a Saturday night. The cynical view would be that once the economy picks up, VMT growth would return right back to where it was.

This poses a question as to whether we should interpret these types of numbers as some permanent trend, or something of an anomaly that is indicative of contemporary economic times. My instinct is that there's some combination of the two happening, and perhaps even a synergistic effect between a bad economy and real tangible changes in users' travel behavior. On the one hand, people drive less because of the economy. On the other hand, people are increasingly moving to cities and riding transit more, as well as all the hypotheses you explained. And perhaps the bad economy causes people begin to realize the high costs that automobile transportation have on their lives.

Todd Litman's picture
Blogger

Recession Effects on VMT

Thanks for your comments, Michael,

Yes, economic growth does affect travel activity, but you'll notice that the VMT growth rate began to decline starting about 2003 and was nearly flat during the subsequent period of employment and economic growth (2003-2007). A number of studies predicted the moderating in VMT growth rates due to fundamental demographic and economic trends (aging population, rising fuel prices, increasing urbanization, etc.). For a review of this literature see my paper, " The Future Isn’t What It Used To Be: Changing Trends And Their Implications For Transport Planning" (www.vtpi.org/future.pdf).

Yes, it is likely that vehicle travel will fluctuate in the future in response to changes in economic activity and fuel prices, but it is unlikely to ever return to the high growth rates that existed during the last century. Our transport planning assumptions need to be adjusted in response.

Todd Alexander Litman
Victoria Transport Policy Institute
www.vtpi.org
"Efficiency - Equity - Clarity"

need to dig down further

Todd,
Thanks for the article and the data. It is encouraging to see this type of trend happening. However, I doubt it is going to immediately change Suburbia-ville City Hall's requirements for traffic studies outlining what intersection widening is required to accommodate a development and background traffic up to 10 years in the future. As they approve new sub divisions etc they will assume, and often rightly so, that traffic will grow in their town.
Is there further data that shows where in the US this vehicles miles driven reduction has come from? Is it in the cities or out in the burbs?
Tim

Tim Barton
www.planningpicture.com

Todd Litman's picture
Blogger

Need To Dig Down Further

Thanks for your comments, Tim.

Yes, too often planning simply consists of extrapolating past trends rather than understanding the underlying factors that affect future needs and conditions. Demographic and economic trends will change future travel demands. Smart communities will prepare for these shifts. As planners, we have a responsibility to alert decisions-makers, but not all will appreciate the implications.

Todd Alexander Litman
Victoria Transport Policy Institute
www.vtpi.org
"Efficiency - Equity - Clarity"

Diminishing Marginal Rate of Return

Can't this also be explained by diminishing marginal rate of returns. At a certain point distances are so vast, and total VMT so high, that an extra mile doesn't gain additional benefit.

Why does planetizen publish this guy?

What did his article tell us? It did not mention that gas prices rose at the end of 2007, and the economy started to slip into chaos as a possible explanation for the reduction in VMT. Maybe the VMT reduction had to due with a poor economy and not preferences (although there has been a shift in preferences, but is not explained or even considered in this article).

Also, there was a rise in WiFi and 3G spots and an increase in devices to access them which may have contributed to the VMT reduction as well. Were commercial vehicles delivering internet purchased good taken into consideration? What about the trips to the CD store that have been substituted by iTunes and the bookstore by Kindle? This article was to simplistic for Planetizen readers.

Not your best work Todd.

“Conspicuous consumption of valuable goods is a means of reputability to the gentleman of leisure”

- Thorstein Veblen

The whole story would be:

What planners really need to know, is what all the people who "used to" or "would have" driven all the extra VMT, are now doing?

Not travelling at all?
Telecommuting?
Unemployed?
Retired? (Demographics)
Travelling by other means?
Public Transport?
Bicycle?
Walking?
Moved residence - TO 1) More convenient location in their metro area
OR 2) Away from their metro area altogether (Note that rural towns are booming, both in population and employment levels. Perhaps cheap and abundant land is the one factor most desired by people? Planners, be ready to embrace the opportunities presented by this possibility.....!)

Todd Litman's picture
Blogger

The Whole Story

Thanks for your questions. As the article discusses, the reduction in total vehicle travel probably reflects a combination of demographic and economic changes, including aging population which reduces commute trips, mode shifting, and more compact land use development. References at the end of the blog (particularly "The Future Isn't What It Used To Be" and "Where We Want To Be") provide more detail on these trends, and future travel surveys should provide more detailed information. These VMT reductions most certainly don't result from population shifts to rural towns, since rural residents are a declining portion of the total U.S. population, and residents of such communities tend to drive more than average.

Note that the reduction in VMT began about 2003 and continuted during subsequent economic boom and bust periods, indicating that these are structural changes rather than short term fluctuations.

Todd Alexander Litman
Victoria Transport Policy Institute
www.vtpi.org
"Efficiency - Equity - Clarity"

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