Your choice of a vehicle is among the most important buying decisions you will make in terms of your overall environmental impact. Private transportation accounts for over 17% of greenhouse gas emissions in the US; only home energy use is as significant a contributor to your global warming footprint. Passenger cars and light trucks are also important contributors to local air pollution problems like smog. Over 175 million people–roughly 58 percent of the US population–are exposed to pollution levels that are too often dangerous to breathe.
While motor vehicle fatalities have steadily decreased over the past decade, driving remains a relatively dangerous activity–the lifetime risk of dying in a traffic accident is 1 in 80. Consumers have been demanding safer vehicles and manufacturers are responding with a variety of crash safety features as well as accident avoidance technologies.
Buying Guide: What to look for
Choose vehicles with the highest fuel economy (highest MPG). Make sure that the fuel efficiency of your choice is substantially better than the average for its class: 22.5 MPG for small cars, 22.4 MPG for midsize cars, 19.0 MPG for large cars, 19.4 MPG for SUVs, 19.2 MPG for minivans, and 16.4 MPG for pickup trucks.
Look for EPA's SmartWay certification mark while shopping. To earn a SmartWay designation, a vehicle must be among the best environmental performers in terms of its greenhouse gas and air pollutant emissions.
Choose the safest vehicles–these get 4 or 5-star safety ratings from the National Highway Traffic Safety Administration (NHTSA). Opt for additional safety features, including electronic stability control (ESC), side air bags, and lane departure and front impact warnings.
All-electric and plug-in hybrid vehicles are generally environmentally preferable to gasoline-fueled vehicles. But remember that the scale of environmental benefits associated with such vehicles differs significantly based on how electricity is produced in your area. Charging an electric vehicle in a state where a large portion of the energy mix comes from burning fossil fuels (coal, oil, natural gas) will significantly increase the amount of greenhouse gas and air pollutant emissions associated with vehicle use. Charging in a state where a large portion of the energy mix comes from renewable sources (hydro, biomass, wind, geothermal, solar) or nuclear power will result in the lowest amount of greenhouse gas and air pollutant emissions associated with vehicle use. The following graphic illustrates the generating mix in different states. Electric vehicles operating in west coast states will generally have lower greenhouse gas and air pollution impacts than vehicles operating in the rest of the country.
Buying Guide: What to avoid
Avoid vehicles with poor fuel economy. Don't buy a larger size or higher horsepower car than you need–these features have major impacts on fuel efficiency and pollution levels. Smaller is usually better. Even if you need a larger car, there are an increasing number of substantially greener choices within most vehicle classes.
Environment scores are assigned to cars by combining product-level environmental indicators (weighted at 75%) with GoodGuide's standard company indicators of environmental performance (weighted at 25%).
Product-level scores for this category are based on the following indicators:
Fuel economy, as measured by EPA estimated miles per gallon for combined city and highway driving
Greenhouse gas impact, as measured by scores developed by the US Environmental Protection Agency (EPA) and the California Air Resources Board (CARB)
Local air pollution impact (e.g., smog); as measured by scores developed by EPA and CARB
Non-driving impacts, covering the environmental damage created by the production and disposal of a car (i.e., materials extraction and processing, auto manufacturing, and end-of-life disposal)
Health scores are not assigned to cars. Instead, GoodGuide reports a car's safety rating from the National Highway Traffic Safety Administration (from one to five stars). NHTSA safety ratings are based on averaged crash test results for front, side, and rollover crash tests. GoodGuide also displays whether Electronic Stability Control is available for that car.
Society scores are based on company-level research. Product-level data on societal performance are generally unavailable for this category of products.