Here is the link to the news article about the California study.

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/09/25/BA4A19S8DQ.DTL

Note that the article says that the study was mandated by the State legislature.

Obviously, these kind of measurements are difficult. But this is a great start and clearly what New York needs to do.