[Porcupine]

I think busy intersections, because your targets are stuck right by you waiting for the light. Also, people are used to the idea of panhandlers at intersections and everyone has seen someone hand money out of the car window.

Is knocking on the car windows that common? Around here they don't really approach the cars unless someone holds money out of their window. That said, I think knocking on the windows would really increase your take. Recently, I gave money to some tweaker that surprised me at my car window - partly because it was a girl, but also because she was "right on top of me" and harder to ignore.