Officers can set up DUI checkpoints where they see fit, and they do not even always have to warn other drivers about it.
However, is it actually necessary for a driver to go through these DUI checkpoints? Or is it legal for them to simply drive around these points?
Avoidance of checkpoints
LifeSafer discusses DUI checkpoints along the roads. As mentioned, officers do not have to tell other drivers that they plan on putting a DUI checkpoint in place. In some states, they must set up notice on the road leading up to the checkpoint. In others, they even have to provide alternative routes for drivers who wish to avoid these stops.
However, a driver does not need a police-sanctioned alternate route in order to avoid a DUI checkpoint. It is valid for a driver to simply turn away when they see one and figure out another route on their own.
The possibility of being pulled over
On that note, these drivers must still abide by the rules of the road. In other words, they cannot make any illegal moves while attempting to avoid the checkpoint. They cannot speed, drive recklessly, make illegal U-turns, cross the double lines, and so on.
Officers will keep watch for cars turning away from the checkpoint, too. They may even look for reasons to pull a car over if they try to leave, such as expired plate stickers or broken tail lights. If they do pull a car over, they may then find further reason to do DUI tests.
Thus, it is better to avoid DUI stops only if the driver has fair certainty that they will not end up pulled over anyway.