San Francisco is one exception in California. "Most" cellular calls within the city are routed directly to the city 911 center, depending on which cell tower your phone connects with. Like OldBaldGuy said, you don't necessarily connect with the geographically closest tower. Anyway, the rest of the cellular calls in SF are answered by the CHP. But I'm in southern Cal now and I'm not sure how it works down here yet. I should find that out.

When I lived in NYC, I believe those cellular calls were also routed to the city dispatchers.