Making traffic worse for everyone but cyclists
"I'm kind of amazed that someone would dare say that 6 percent of trips are by bicycle! Where's the proof? The US Census Bureau reports that number as 2.2 percent. Check it out."
To be fair to the bike nuts, the Census Bureau chart you've linked is about "means of transportation to work," not all trips in the city by bicycle. Even so it's interesting to note that the commuting-by-bicycle number hasn't changed much in years: The MTA's San Francisco Transportation Fact Sheet of October, 2008 (available on MTA's website), tells us that 80.6% of city residents either drive/carpool, take public transportation, or "motorcycle, taxicab or other" means to get to work, as opposed to 2.3% who bike to work (9.6% walk to work, and 7.6% work at home).
And the San Francisco County Transportation Plan of July 2004 (also available online), has even lower figures for "all internal trips" by bikes, putting the percentage at 1% without giving a percentage for bike commuters, probably because the number is embarrassingly low (page 51).
In short, the city is about to implement a Bicycle Plan that will make traffic worse for more than 80% of San Francisco's commuters.
The SFCTA's Transportation Plan has this interesting paragraph about transportation and the city's economy:
Visitor travel and tourism are integral to San Francisco's economy. The city attracts almost 14 million visitors per year. Of this total, about 10 million arrive from outside the nine-county Bay Area. The transportation needs of business travelers, tourists and other visitors must be planned for in order to support this growing sector of the city's economy. For example, visitors unfamiliar with the city's transportation system rely on easy-to-read maps, good signage, and pleasant walking, transit and taxi environments to navigate the city's attractions easily and efficiently (page 41, emphasis added).
Do these folks ride their bikes into the city? Nope, according to the Visitor's Bureau---which says the city actually had more than 16 million visitors in 2007---25% of the 4.74 million visitors who stayed in city hotels in 2007 rented cars while in the city. Most of the four million visitors to the city from the Bay Area probably drove into the city, though some no doubt arrive on BART.
The Bicycle Plan will not only make commuting worse for more than 80% of the city's population, it will also make negotiating city streets more difficult for millions of tourists, who, according to the Visitor's Bureau, spent $8.24 billion here in 2008, providing $527,612,802 in direct revenue to the city.