Despite the best efforts of some legislators in Austin to whittle away at the protections of the Fourth Amendment, DWI roadblocks or sobriety checkpoints are still not legal in Texas.
But they are in Missouri, and Randy England notes an interesting tactic used there:
The police sometimes get clever in setting up such roadblocks. A sign on the highway will say “Sobriety checkpoint ahead - be prepared to stop.” The police then setup the roadblock–not on the highway–but at the next exit.
The idea is that drunk drivers will “select” themselves by taking the exit to avoid the roadblock. Like checking into a roach motel. Too late, the driver realizes, he put his head in the noose.
Of course, once the police have a car stopped and the window is rolled down, the party is over in the time it takes to smell the driver’s breath.
Well, I have to admit it’s clever. And every 2 years when the legislature meets, it's more and more likely to be coming to us in Texas.