In California they are called "Sobriety Checkpoints." The policy is that there is a big lighted sign that says there is one ahead and there must be at least two opportunities to turn off the street before reaching the checkpoint. The catch here is that there or motorcycle cops stationed at these "turn off streets" and if you aren't wearing your seatbelt or you have a signal/brake light out or anything like that, they stop you for that, then they ask for your liscense and registration and proof of insurance - then they ask you if you've been drinking...
In the article above, they posted the dates and places of the checkpoints comming up and gave a phone number to check to make sure. I'd say if I were going to go drinking and driving I would deserve it if I got into one of those.
highway checkpoint - shades of 1930s GermanyWe had the local PD set one of these up near the bar a couple weeks ago. I called about eight nearby bars to let them know to tell their customers not to go that way. Hopefully they made so few arrests the powers-that-be will decide it was a waste of time.
One of our semi-regulars walked down the streets and was lecturing the people waiting in line about their constitutional rights. The checkpoint guards threatened to arrest him, until he dared them too. They seemed in poor humor. I hope the calls worked. >:)
-Eric