VMT Reductions: An Excellent Idea When Correctly Evaluated

Todd Litman's picture
OK Bob – I'll Take Your Challenge

Last year, California, passed SB 375, which requires regional governments to develop smart growth-oriented land use and transportation plans aimed at reducing VMT. Last month the Senate Committee on Commerce, Science, and Transportation, introduced the Federal Surface Transportation Policy and Planning Act of 2009 (S1036), which includes goals to "Reduce national per capita motor vehicle miles traveled on an annual basis" and "Increase the total usage of public transportation, intercity passenger rail services, and non-motorized transportation on an annual basis."

These 'mobility management' goals are raising the ire of highway advocacy groups such as the Highway Users Alliance and the Reason Foundation. Similarly, Alan Pisarski's article in the January ITE Journal, "The Nexus of Energy, Environment and the Economy" argues that VMT reductions and smart growth would harm consumers (my response letter was published in this month's issue). In the current Surface Transportation Innovations, Robert Poole calls VMT reduction goals "A Terrible Idea" and challenges proponents to prove they can be cost effective. I'll accept that challenge.

This criticism of mobility management reflects the old transportation planning paradigm, which assumed that "transportation" means automobile travel, and increased mobility is always desirable. The new paradigm assumes that the goal of transportation is accessibility (people's ability to reach desired goods, services and activities), and there is an optimal level of mobility, beyond which additional vehicle travel is overall hamful, considering all benefits and costs.

The study, Socially Optimal Transport Prices and Markets investigates this optimal level, defined as the amount and type of mobility that consumers would choose under efficient market conditions, which requires adequate consumer options, efficient pricing and neutral planning practices. The research indicates that current North American transportation markets are distorted in various ways that result in economically excessive mobility. These distortions include underpriced roads and parking, dedicated roadway funding, and generous parking supply and density restrictions in zoning codes. In a more efficient market, consumers would choose to drive less, rely more on alternatives, and be better off overall as a result.

The old paradigm used a "reductionist" approach to evaluate solutions to transportation problems, assigning individual problems to specific agencies with narrowly defined responsibilities. For example, transportation agencies were only concerned with congestion reduction and environmental agencies were only concerned with emission reductions. The new planning paradigm is more comprehensive and integrated. It assumes that transportation agencies have multiple objectives and should cooperate with other organizations to implement integrated solutions, for example, selecting congestion reduction strategies that also reduce emissions and improve mobility for non-drivers, and selecting emission reduction strategies that also help reduce traffic congestion and increase mobility options.

The new paradigm recognizes that mobility management can help achieve multiple objectives, including congestion reductions, road and parking facility cost savings, consumer savings, traffic safety, energy conservation and emission reductions, improved mobility options for non-drivers, and improved public health and fitness. Described differently, each ton of emission reductions provided by mobility management provides many times the total benefits as a ton of emission reductions from more fuel efficient vehicles, because VMT reductions achieves other planning objectives, while increasing vehicle fuel efficiency makes driving cheaper, which stimulates more vehicle traffic and exacerbates problems such as congestion, accidents and sprawl.

Critics such as Poole claim that mobility management is expensive, apparently based on the cost of building new transit systems, the only VMT reduction strategy they think about. But there is a large number of VMT reduction strategies, many with modest costs and numerous benefits; they are often the most cost effective way to improve transportation. For example, increased fuel taxes, Pay-As-You-Drive insurance and registration fees, and more flexible parking requirements have low implementation costs and provide diverse benefits. Efficient road and parking pricing can have modest implementation costs and many benefits if properly implemented. More compact and mixed land use development can provide savings. Improving walking, cycling and public transit services is often cheaper than accommodating additional automobile travel, considering all costs (roads, parking and vehicle costs). As use of alternative modes increases, their unit costs decline; the apparent high unit costs of alternative modes is really a result of automobile-dependent transportation planning (Pucher and Buehler 2009).

Many current emission reduction planning efforts ignore mobility management altogether (Gallagher, et al. 2007) or only mention them incidentally (McKinsey 2007). As a result, currently proposed emission reduction efforts will fail to implement mobility management as much as optimal and so will miss an opportunity to help address other planning objectives such as congestion reduction, traffic safety, consumer savings and improved mobility for non-drivers. More comprehensive analysis can give mobility management strategies the support they deserve. The few studies that consider TDM strategies and their cobenefits indicate that strategies which reduce VMT are effective, cost effective, and essential for achiving significant emission reductions (Burbank 2008).

Mobility management can directly benefit consumers. In public lectures I often ask my audience, "Compared with your current travel patterns, how many of you would prefer to drive more than you currently do, and how many would prefer to drive less, provided that alternative modes are convenient, comfortable and affordable?" In virtually every case the majority of audience members would prefer to drive less and few want to drive more than they currently do. Current demographic and economic trends are increasing demand for alternative modes, so it makes sense to invest now in a more diverse and efficient transportation system to prepare for the future.

Critics could argue that VMT reductions should be an outcome of transportation market reforms, such as more efficient road and parking pricing and least-cost transportation planning, rather than a policy goal. That would be fine if economists were in control, but significant reforms are unlikely to be implemented without VMT reduction goals, and setting VMT reductions goals is useful for strategic planning, since it allows resources that would otherwise be dedicated to expanding transportation facilities to accommodate anticipated traffic growth to be used instead to increase transport system efficiency, for example, to improve walking and cycling facilities, HOV lanes and transit service improvements. Similarly, VTM reduction goals can help coordinate transportation and land use policies to improve accessibiltiy. This, of course, is what critics fear, that transport policies will begin to emphasize system efficiency rather than continued expansion.

For most the last century, transportation agencies used "predict and provide" planning: they expanded roads and required more parking in anticipation of traffic growth, and ignored other modes. This resulted in communities where driving is convenient but accessibility by other modes is difficult, leading to a self-fulfilling prophesy of increased automobile ownership and use. Establishing goals to reduce VMT and increase use of alternative modes can lead to planning reforms that result in better consumer options and more economically efficient transportation systems. For example, these goals can give transportation agencies a mandate to support more comprehensive and integrated transportation planning; additional investments in alternative mode; more flexible funding; more efficient road, parking and vehicle insurance pricing; and development policy changes to create more accessible and multi-modal communities.


For more information

Cynthia Burbank (2008), Global Climate Change:  Transportation's Role in Reducing Greenhouse Gas Emissions, AASHTO Annual Meeting; at www.transportation.org/sites/aashto/docs/Burbank%20-%20Global%20Climate%20Change%20Transportations%20Role%20in%20Reducing%20Greenouse%20Gas%20Emissions.ppt.

CCAP (2009), How Much Can We Slow VMT Growth? The Potential Savings of Implementing Best Practice Everywhere, Center for Clean Air Policy; at www.ccap.org/docs/resources/460/How%20much%20can%20we%20slow%20VMT%20growth%20May%202008.pdf. 

Commerce Committee, Federal Surface Transportation Policy and Planning Act of 2009, U.S. Senate (http://commerce.senate.gov/public/index.cfm?FuseAction=PressReleases.Detail&PressRelease_id=6e1be4c5-07d4-41e9-8fda-4f0655b31848).

ECMT (2008), The Cost and Effectiveness of Policies to Reduce Vehicle Emissions, Round Table 142, European Conference of Ministers of Transport; at www.internationaltransportforum.org/jtrc/DiscussionPapers/DP200809.pdf.

Reid Ewing, Keith Bartholomew, Steve Winkelman, Jerry Walters and Don Chen (2007), Growing Cooler: The Evidence on Urban Development and Climate Change, Urban Land Institute and Smart Growth America (www.smartgrowthamerica.org/gcindex.html). 

Ryan Falconer and Professor Peter Newman (2008), "Transport Policy for a Fuel Constrained Future: An Overview of Options" World Transport Policy & Practice (www.eco-logica.co.uk), Volume 14, Number 3, pp. 31-45; at www.eco-logica.co.uk/pdf/wtpp14.3.pdf.

Kathleen Leotta (2007), Implementing the Most Effective TDM Strategies to Quickly Reduce Oil Consumption, Post Carbon Cities (http://postcarboncities.net); at (http://postcarboncities.net/files/Leotta_ImplementingTDMtoQuicklyReduceOilConsumption.pdf).  

Todd Litman (2005), "Efficient Vehicles Versus Efficient Transportation: Comparing Transportation Energy Conservation Strategies," Transport Policy, Volume 12, Issue 2, March 2005, Pages 121-129; available at www.vtpi.org/cafe.pdf.

Todd Litman (2006), Win-Win Transportation Emission Reduction Strategies, Victoria Transport Policy Institute (www.vtpi.org); at www.vtpi.org/wwclimate.pdf 

Todd Litman (2007), Smart Emission Reduction Strategies, VTPI (www.vtpi.org); at www.vtpi.org/ster.pdf.

Todd Litman (2009), Letter to the Editor, in response to Alan Pisarski's article "The Nexus of Energy, Environment and the Economy: A Win, Win, Win Opportunity" (http://www.ite.org/mega/JB09AA30.pdf), ITE Journal (http://www.vtpi.org/ITE_letter_may2009.pdf ).

Robert Poole (2009), "Targeting VMT: A Terrible Idea," Surface Transportation Innovations, Issue 68, June; http://reason.org/newsletters/stinnovations

Robert Poole (2009), "Reducing Greenhouse Gas Emissions Without Reducing Mobility," Reason Foundation Public Works Financing, Issue 68, June; http://reason.org/news/show/1007715.html. 

John Pucher and Ralph Buehler (2009), "Sustainable Transport that Works: Lessons from Germany," World Transport Policy and Practice, Vol. 15, No. 1, May 2009, pp. 13-46 (http://www.eco-logica.co.uk/pdf/wtpp15.1.pdf ).

Peter Samuel and Todd Litman (2001), "Optimal Level of Automobile Dependency; A TQ Point/Counterpoint Exchange," Transportation Quarterly, Vol. 55, No. 1, Winter, pp. 5-32.

Yang, et al. (2008), 80in50 Scenarios for Deep Reductions in Greenhouse Gas Emissions from California Transportation: Meeting an 80% Reduction Goal in 2050, Sustainable Transportation Energy Pathways Project, Institute of Transportation Studies, University of California (http://steps.ucdavis.edu); at http://steps.ucdavis.edu/research/Thread_6/80in50.

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



The New Planning Paradigm

Part of the new planning paradigm is to recognize that one important role of transportation planners is to connect people. How we connect people depends on the speed of the network. Early America experienced a development form where land uses were close together in a mixed form because the speed of the network was based on walking (or riding a horse). As the network speed increased especially through the use of automobiles, our urban form spread out. This form of development is associated with many of the externalities that Todd mentions and has resulted in limited travel choices.

The new transportation planning paradigm focuses on connecting people through closer proximity between land uses because it offers more travel choices, reduces energy demands, and minimizes environmental impacts. These objectives are commonly found in many communities, but are often absent in transportation analysis because of a focus on vehicle travel (i.e., LOS). That has started to change recently with some communities and at least one community (Yolo County , CA) has embraced the new planning paradigm by introducing a VMT threshold to help guide new development instead of being focused on vehicle LOS. For more information, check out the links below.

Summary article about Yolo County's approach:


Link to the full Yolo County General Plan Draft EIR Transportation Impact Section (refer to page 240).



VMT Reductions: An Excellent Idea When Correctly Evaluated

Once again, Todd Litman has hit the nail on the head. The silo thinking habit is our biggest obstacle to sustainability.

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