While not as popular as they used to be, you still hear references to DWI checkpoints. In case you don't know, that's basically a place where law officers will set up and stop every driver that comes through. If you travel near the border you are probably familiar with checkpoints - and have probably been stopped at a few.
Besides border checkpoints, police can use checkpoints for other purposes, including checking for driver's licenses and insurance information, and checking to determine whether drivers are intoxciated. Those are sometimes referred to as "sobriety checkpoints".
Back in 1990 the Supreme Court held DWI checkpoints could be permissible in a case called Michigan Dept. of Public Safety v. Stitz. The court did not go so far as condoning all such checkpoints. Instead, the Court set out a balancing test, that looks at the interest of the state in preventing drunk drivers and balances that against the level of intrusion to the individual's right to privacy that is caused by the checkpoint. In Michingan, the State government had adopted a statewide program for sobriety checkpoints, which included guidelines on how they were to be conducted. Those guidelines were binding on each police department within the State.
Unlike MIchigan - and some other states - Texas has no statewide policy or guidelines that govern checkpoints. Our Court of Criminal Appeals held back in 1994 in State v. Holt that without such a policy checkpoints are not permissible. The agency that would be responsible for such policy would most llikely be the Texas Department of Public Safety - pursuant to a request from the State legislature. However, it's now been 20 years, and there still is no statewide policy governing DWI checkpoints.
What that means is that as long as you aren't near the border (because border checkpoints are legal), you can drive down the highway without fear of being stopped at a checkpoint.
However, that doesn't mean police can't focus on places where they know intoxicated drivers are likely to be - the exit for a popular bar might be one such place. There's nothing to prevent them from setting up and watching everyone come out. They can't stop you merely because you're leaving a bar. But if you commit a traffic violation you are fair game. Once you are stopped if they smell alcohol on you you're probably in store for an extended visit with the officer.
Are checkpoints a good thing or bad thing? There's no doubt they can be effective, but there's also no doubt they are a huge inconvenience to the public. Everyone is in a hurry, and no one wants to sit and wait in line while the police check everyone out. No matter how you do, it's an intrusion on your privacy. Some states have held it's a worthile intrustion. Perhaps it's because we are so dependent on cars - but so far Texas failed to follow suit. Personally I think that's good thing - even though DWI checkpoints might be good for business.
While you don't have to worry about checkpoints, that doesn't mean you should feel free to drive while you're intoxicated. The best advice is still not to drink and drive; or if you are going to drink, get a designated driver. It's definitely better - and cheaper - than having to hire a lawyer.