Roadblocks – what’s the hold up?
Nationally, roadblocks are legal. The United State Supreme Court ruled that it is not unconstitutional for a roadblock to check for sobriety or to ask questions to the general public in response to a crime. However, temporary roadblocks to stop cars and investigate a larger number of drivers in the hope of discovering alcohol-impaired driving violates Minnesota’s constitution (Min. Const. Art.1, §10). In Minnesota, drivers may not be subjected to an investigative stop without first having objective and individualized articulable suspicion of the driver.
However, there are a few exceptions: for a storm warning, the public interest outweighs the slight privacy request to help produce a warning to non-residents. A roadblock that is designed to protect rather than check for sobriety is constitutional.
For example: a roadblock may be set up to warn drivers that the roads ahead are flooded and that there is no access, but if they happen to notice the smell of booze, you could end up in trouble!