“When it comes to transport, we’ve become obese. I mean this in multiple senses. Our population of vehicles has burgeoned; already around 1 billion worldwide, it’s expected to double within just 20 years. The vehicle miles we travel, or VMT, continue to swell; just in the U.S., for instance, VMT now fluctuates around 250 billion per month – trillions per year – and grows each month by an average 200 million more. Even our waistlines have expanded due to excess motor vehicle travel; one study attributes six extra pounds to the extra driving done by typical suburbanites.”
Losing Transport Fat with Car Diets:
Cutting VMT Instead of Calories for Multiple Benefits
- By Katie Alvord
We’re all too familiar with the downsides of these trends. VMT growth means that greenhouse gas emissions continue out of control, making mitigation of climate change ever more costly and difficult. Vehicles added to the global fleet, still mainly internal combustion and petrol-powered, further denigrate air quality and sicken urban populations. Additional health problems stemming from lack of exercise and obesity – heart disease, diabetes, and more – shorten lives and strain budgets, costing $150 billion per year in the U.S. alone.
To the various interest groups grappling with these major issues, here’s a suggestion: consider car diets. The “diet” – most often associated with cutting consumption of calories – can be a useful model for addressing all these issues at once. Car diets – here defined as cutting not calories, but VMT – can be approached both on an individual and collective basis, and have benefits both ways.
We might use cuts in VMT as measurable, enforceable goals to address all these issues, and total VMT as an indicator of our progress. The wonks among us might even want to add a VMT RDA – a recommended daily allowance for vehicle miles traveled (the lower the better, I’d advise) – to the already acronym-rich transport lexicon.
For individuals, the benefits accrue in health and fitness. Various studies support this. Consider, for instance, research announced last month which found that transit users weigh less. It turns out that regular walking to and from transit stops, even for short distances, is enough to keep pounds off. A typical rider who cuts VMT by using transit for about a year will lose about six and a half pounds, or nearly three kilos. Using transit reduces the risk of becoming obese by 81%.
Around the same time, another study found that as little as five minutes a day of cycling makes a measurable difference in helping women lose weight. As Harvard School of Public Health’s Anne Lusk, the study’s lead author, recommended: “We need to provide the infrastructure or facilities so that more people could comfortably bicycle.” A policy of promoting strategies that cut VMT could lead to such a result.
Already out for a few years is the finding referenced above, that car-dependent suburban dwellers average six pounds heavier than residents of the most compact and walkable city centers. In measuring the health effects of sprawl, researchers found that every increase in the degree of sprawling development – and therefore in VMT – added more to residents’ average weight. To reduce obesity, study authors recommended that communities be restructured to encourage more physical activity in routine daily life. The message here moves beyond “build it and they will come” to “build it and they’ll come lose weight.”
Cutting VMT also saves money – important at a time of widespread economic belt-tightening both individually and collectively. For society, benefits accrue in multiple realms. A lower VMT means better public health, less strain on government budgets, cleaner air, fewer greenhouse gas emissions, and the energy savings that come from lower oil consumption.
These results call for better public investment in transit, cycling and walking facilities. But an individual needn’t wait for that to go on a car diet. To try this, start by figuring out how many miles per week you drive. Then cut that by 5, 10 or 20 percent, depending on how low-VMT you want to go. Use the strategy of movement elimination by asking whether you can access what you need without traveling – electronically, perhaps. Use travel substitution by replacing car miles with walking, cycling, or transit.
Governments can support car diets with a range of policies that aid individuals in reducing VMT: compact, clustered land use patterns; mixed-use and transit-oriented development; improved facilities for walking and cycling; low-fare or free transit, depending on community conditions. These strategies benefit citizens, and in turn benefit government, as the public health advantages alone may be worth the price of such policies.
With the range of issues addressed by car diets, the VMT-cutting strategy can be important for multiple interest groups. Forging stronger links between reducing motor vehicle travel and issues such as air quality, climate change and public health gives more groups an incentive to engage in transport reform, and can be an important part of helping that reform to move forward.
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About the author
Katie Alvord is an award-winning freelance writer and author of Divorce Your Car! Ending the Love Affair with the Automobile (New Society Publishers, 2000, http://www.newsociety.com ). She blogs at