I hear lots of sirens but I don’t see any accidents

So my apartment is right off of Market Street so there is a lot of traffic. I hear sirens all during the day and at night. Even while I am walking I hear them and see ambulances and fire trucks weaving through traffic. The  only thing that seems out of  the ordinary is that I never see an accident. Where are all these emergency vehicles going? In Phoenix I would always see accidents on the highways and side streets, but I haven’t seen on in SF in 3 weeks. Seems odd to me…