Welcome to PermaCities: San Francisco! The booming tech industry and growing popularity of urban living makes for some of the highest rents and longest commutes in the country. Just to stay affordable, the city needs to add tens of thousands of housing units a year. Then there's the traffic problem: while cycling and transit use are up, unsafe streets and intersections remain a problem for cyclists and pedestrians. Finally, as energy and food prices continue to rise, how can SF become more self sufficient?