Now it takes just slightly over one, since Hwy 85 works as one big diagonal. Transportation is an important aspect of social function. Remember, when you were a little, little kid, you could only go visit the kids next door or down the block. And if they were boring or stupid, tough. Then you get friends all over the city, or in other cities.
Cars are the only simple option.
I have a number of friends in San Francisco and Santa Cruz who don't have cars, and while there's a fair bit of social activity going on in walking distance of their houses, there's a lot they miss out on. I'll admit, having party invitations on the same night in three separate counties can get weird, but being a social dragonfly can be fun, not to mention crucial for sanity. With as odd as those of us in the SF set are, we're lucky if we have a friend with our same interests within bicycling, let alone walking, distance. And if we do, we're liable to set up a co-dependent situation. I drive about 100 miles tonight to go see a friend's play.