A question that runs through your mind as the siren and lights are in your rear view mirror.  Why is a San Francisco police officer stopping me?  An officer needs probable cause to pull you over, or in layman's terms, a reason to believe you have committed a crime.

The most common reasons are as follows:

1. Driving on or over the lane divider
2. Drifting into the other lane
3. Making a wide turn
4. Making an illegal turn
5. Weaving
6. Braking frequently
7. Nearly missing an object in the road, or another vehicle
8. Driving very slowly, below the speed limit
9. Swerving
10. Driving at night with your headlights off
11. Not making a turn signal, or having your turn signal on inappropriately
12. Stopping in the middle of the road
13. Accelerating or deaccelerating too fast
14. Following another vehicle too closely
15. Speeding

And the list is endless.  Which is why is is important to be careful driving, especially at night, if you have been drinking, and to not drive at all if you really have had too much to drink.  A reason for a San Francisco police officer to stop you can be a small infraction, but the consequences can be expensive.