Check out the web sites at the bottem to help you figure your cost of commuting alone. Register to receive e-mail notices about Spare the Air days so that you can take some alternative way to work on those days and help us all breathe easier. This site has all the information about air quality and regulations in the Bay Area including vehicle buy back program for 1981 or older cars, information on incentives for alternative fuel vehicles, reporting of smoking vehicles and a guide to low emission vehicles to name just a few. Check out this web site for information from 1995 to present. So if you need a mid-sized car, this guide would tell you which ones are the cleanest ones.
Most alternatives are cheaper.
From the department of energy, find out and compare fuel economy of new cars. They also have gas mileage tips and links to other sites including information on hybrids and alternative fueled vehicles. A PowerPoint presentation on transportation and how it affects our environment in the Bay Area, and how we can have less of an impact using alternate transportation.