The transportation sector is a significant contributor of greenhouse gas emissions. Greenhouse gases, such as carbon dioxide (CO2), have been implicated in contributing to global climate change, an increase in temperature of the Earth’s surface that can cause polar ice caps to melt and sea levels to rise— all with disastrous effects on our ecosystem. In addition, some greenhouse gases have been identified as contributing to the destruction of our atmospheric ozone layer, resulting in less protection from the sun’s harmful radiation.

According to the US EPA, in 2003, the transportation sector accounted for approximately 27 percent of total US greenhouse gas emissions. This percentage is expected to continue to rise due to increased economic growth, increased movement of goods by trucks and aircraft, and continued growth in personal travel. In fact, the US Department of Energy expects transportation energy use to increase by almost 50% between 2003 and 2025.