Climate Change and Air Quality
The Vehicle Trip Reduction Ordinance was enacted in 1992 in response to increasing concerns about the impact on air quality caused by driving. The ordinance includes a set of measures to discourage, and provide alternatives to, vehicle trips and trips by single-occupancy vehicles made by residents of and visitors to Cambridge necessary to further the goals of the Clean Air Act.
According to the city’s 1998 GHG emissions inventory, transportation is responsible for about 12% of the GHG emissions in Cambridge. This is a smaller proportion than in communities in other parts of the country. The national average is about a third.
Several factors contribute to this smaller role:
- Cambridge has a large institutional/commercial component with high energy use.
- Trips tend to be relatively short because the city is geographically small and dense, mostly with mixed-use development, and destinations close to each other.
- An unusually large percentage of people walk or bike in Cambridge, because there is a high percentage of students, the streets are bicycle and pedestrian-friendly, and the public transportation system provides an easy way to get to many destinations.
Somewhat offsetting these factors is the volume of truck and commuter traffic passing through the city.
Strategic Approaches to Reduce GHG Emissions from Transportation
There are two strategic approaches to reducing GHG emissions related to transportation:
- Reducing the vehicle miles traveled (VMT)
- Reducing the GHG emissions per mile of travel.
Promoting use of transit is an example of the first approach; replacing conventional vehicles with electric-powered vehicles is an example of the second approach.
The City of Cambridge has a comprehensive program to reduce VMT and has developed a pilot program to provide electric vehicle charging stations available to the public across the city.