http://www.msnbc.msn.com/id/12191001/site/newsweek/
Newsweek has an online commuting survey wherein 85% of respondents so far commute by car. it's mentioned in this thread in the commuting forum:
http://www.bikeforums.net/showthread.php?t=191373
Originally Posted by newsweek-msnbc survey
If you commute in a car, are you usually alone? * 26098 responses
Yes
90%
No
9.6%
People come to this forum talking about how people should have the freedom to use their hard-earned money on whatever kind of car they want, because it's legal, blah-de-blah, and one of the significant arguments is that people don't want government looking in to whether they're using their vehicle responsibly. Well, here you go-- if you think single-occupant use of ~3000 pound vehicles is generally irresponsible, people are not using their vehicles responsibly. Those SUVs and cars that are used for commuting etc., are (at that time) not being used because they can carry 5 to 8 people, or because they can carry/tow 800 to 5000 lbs of stuff around.
They
are being used because, if you have one and it runs, it's convenient, and easy to ignore the costs to others in terms of environmental harm and buggering up urban planning.
disclaimer: the Newsweek survey is non-scientific. However, I doubt its results are inaccurate enough to affect the point I'm making here.