This scholarly paper was sent to us by Patrick Adams.  It is about all kinds of traffic checkpoints and has many references attached – court decisions, etc.  Thank you Patrick (David) Adams!

Imagine driving to the local school to pick up your kids. It’s three o’clock in the afternoon, and the day is unseasonably nice. The sun is shining and your otherwise routine schedule is pleasant enough. You drive around a final corner to reach your destination when you suddenly approach a group of police cars. You abruptly halt and observe several officers standing right in the middle of the street. They signal you to stop. You pull up to the stopping point and roll down your window, wondering what could be happening.  (Download a pdf of the full paper here http://www.independent.org/pdf/working_papers/80_checkpoints.pdf )