Transportation

In economics, the word externality refers to costs or benefits of a good or service not reflected in its price. For example, making gasoline requires petroleum extraction, transportation, and refinement; driving creates pollution, noise and congestion.  These in turn cause health and environmental damage.

While increasing energy efficiency has considerable benefits, significant barriers exist. Efficiency potential is spread throughout millions of individual homes and businesses, requires upfront investments and shows returns only over time. This makes efficiency no one’s first priority.

High-occupancy vehicle lanes are intended to both speed traffic and improve air quality. This is done by dedicating a lane to cars with two or more occupants, thus reducing the number of vehicles traveling on the road. This both speeds traffic flows and reduces pollution. Some have argued, however, that if underutilized, such lanes can create congestion.

While national pedestrian fatalities in 2008 declined by 16% from a decade earlier, that year car crashes caused 4,378 pedestrians deaths and injured 69,000 pedestrians. Urban areas were consistently found to account for a larger proportion of such deaths and injuries.

Automotive transportation, one of the largest sectors of the U.S. economy, has numerous societal benefits but also many downsides — pollution, fatalities, congestion. Getting the price individuals pay for driving to reflect its true cost to society is one of the most significant challenges of public policy.

Between 1950 and 1990, while the population of U.S. metropolitan areas grew 72%, the central cities shrank by 17%. Factors that could account for central cities’ population decline include faster commutes, population sorting due to racial and social preferences and perceived increases in city crimes.

Once part of the urban fabric of the United States, streetcars declined as the automobile rose during the 1930s and 1940s. In the last several decades, however, streetcars have returned to popularity — more than 40 new systems are in planning, construction or operation.

Travel demand and vehicle use rates have generally increased from the 1970s through the early 2000s. These trends often inform projections about global energy growth, increases in greenhouse gas emissions and climate change scenarios.

As gas prices rise, people tend to shift from driving personal vehicles to using public transit. However, the extent of this change and the interplay between fuel price spikes and transit usage are not precisely known.

In the quest for increased energy efficiency and smaller carbon footprints, many individuals are now making more conscious consumer choices, looking for greener alternatives in everything from household appliances to hybrid vehicles. However, the basic structure of homes, as well as the areas in which they were built, may represent deep challenges to achieving real cuts in personal and family energy consumption.