"In February 2009, city officials and race sponsors announced major changes to the race regulations. The regulations included an official ban on floats, alcohol, drunkenness and nudity.[14] The changes were made to assuage the concerns of San Francisco residents along the parade route, who say the race has gotten out of hand in recent years.[15] The news sparked outrage amongst many Bay Area residents who said the changes would destroy everything that has made the race a national treasure for most of the last century.[14] On February 27, 2009, city officials and race organizers announced that they were lifting many of the restrictions.[16] In particular, floats will now be allowed as long as they are registered, and nudity is not mentioned anywhere in the new restrictions. Although the bans on alcohol and drunkenness technically remain in effect, all "zero tolerance" language has been removed.[17]"
from:
http://en.wikipedia.org/wiki/Bay_to_breakers