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List of State Officials - Martin O'Malley, Governor; Anthony Brown, Lt. Governor; Shari T. Wilson, MDE Secretary 

Volume IV, Number 2

 December 2009

eMDE is a quarterly publication of the Maryland Department of the Environment. It covers articles on current environmental issues and events in the state. 

"Vehicle Miles Travelled" and Air Pollution in Maryland

By Tim Shepherd and Marcia Ways, Air and Radiation Management Administration

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Marylanders drove an average of 154 million miles a day last year. That’s the equivalent of more than 6,000 trips around the world, and the more we drive the more we pollute.

Reducing Vehicle Miles Travelled is often perceived as someone else’s problem. But everyone who drives can reduce their “VMT.” Our collective reward is a cleaner environment and healthier air to breathe. 

For each mile we drive, our vehicles emit pollutants. These include nitrogen oxides (NOx) and volatile organic compounds (VOCs), both precursors to ozone, as well as carbon dioxide, the primary greenhouse gas associated with climate change.

Motor vehicle emissions account for about a third of the total ozone-forming emissions and greenhouse gas emissions in Maryland. Motor vehicle emissions can be attributed to three factors: vehicle technology, fuel, and VMT. Over the past decades, many new technologies have been implemented for fuels and vehicle technology. Initiatives such as the Maryland Clean Cars Program and the Reformulated Gas Program have drastically reduced emissions. Today’s automobiles and fuels are as much as 90 percent cleaner than they were in the early 1990s.

Despite these technological advancements, transportation continues to account for a large part of the State’s emissions. Although vehicle emissions have drastically decreased on a per-mile basis, VMT has continued to increase at an average rate of 2 percent each year since 1990. It is projected that by 2030 VMT will increase by 40 percent compared to current levels.

The State of Maryland has two main sources of VMT data: the federal Highway Performance Monitoring System (HPMS), which is implemented through the State Highway Administration, and the transportation models used by the local metropolitan planning organizations. The HPMS includes data on the extent, condition, performance, use, and operating characteristics of the nation's highways. Tracking VMT is made possible through the use of counters (usually in the form of a set of strips) strategically positioned across designated roadways.

Metropolitan planning organizations such as the Baltimore Metropolitan Council and the Metropolitan Washington Council of Governments provide information for states on VMT, transportation issues, and planning. In Maryland, these organizations project VMT by using the latest, local transportation models that take into account socioeconomic data such as population, age distribution, and the number of vehicles per household. These models also attempt to account for land use, or how areas are zoned. Land use patterns have a significant impact on how often people need to drive, as opposed to walking or using public transit. 

Comfortable and frequent public transit service, the placing of new development and schools in population centers, higher residential/retail densities, and reduced parking supply can create communities that invite people to ditch their cars and reduce their VMT. And we can make choices in our own lives, such as car-pooling, combining trips, using mass transit, working from home, biking, and choosing to live closer to work to reduce our VMT.

It will not be easy. It requires all of us to change our driving habits. But reducing VMT means reducing pollution.

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©2009 Copyright MDE

 
Editorial Board
Maryland Department of the Environment
1800 Washington Boulevard, Baltimore, MD 21230
http://mde.maryland.gov/
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