San Francisco should get rid of the cars.
You can start in a small part of the city and gradually expand out from there. The streets can be used for new housing or for just letting it go back to nature.
When Jello Biafra ran for mayor of San Francisco in 1979, one of the components of his platform was to ban cars in the city.
Berkeleyite Alfred Twu has drawn a rad comic imagining what San Francisco would be like without cars.
San Francisco is a transit-first city, meaning that it's the official policy of the SFMTA and the city to encourage the use of public transportation over private driving.