In many/most cases, if it was suggesting walking for 45 minutes It who? A forty-five minute walk in San Francisco will take you nearly halfway across town (a

In many/most cases, if it was suggesting walking for 45 minutes It who? A forty-five minute walk in San Francisco will take you nearly halfway across town (assuming you can walk a 15 minute mile). My break even time was closer to 20 minutes than 45 (if I didn't see a train coming I'd just walk 20 minutes to the subway). Muni has pretty high coverage standards that allow you to get pretty much within 1/8 mile of anywhere in the city during most hours of the day. The cost is that the density of stops makes it difficult to speed up service.