DUI Checkpoints are flat-out illegal in 12 states. In Ingersoll v. Palmer, the California Supreme Court upheld the legality of sobriety checkpoints in California. The decision also established several "functional requirements" that law enforcement must abide by in order to ensure that the stop does not violate your constitutional protections.
What Happens at a DUI Checkpoint?
During a DUI Checkpoint, law enforcement is permitted to briefly detain you in order to determine whether you are DUI by looking for signs of intoxication, such as odor of alcohol, slurred speech, bloodshot eyes, or open containers.
If the police officer identifies any sign of intoxication, he is permitted to pull you aside to conduct further investigation.
If no sign of intoxication is immediately identifiable, he is required to let you drive on without further delay.
Requirements for a Valid Checkpoint - Supervising Officer
As stated above, law enforcement must abide by strict requirements in conducting a sobriety checkpoint.
One of the requirements is that the "when" and "where" must be decided by a supervising officer, and not a "field officer" (i.e., patrol officer). The supervising officer must also, in advance, decide what neutral formula will be used to decide who to stop, i.e., every other car, third car, fifth car, etc.
Four different requirements determine the adequacy of a location for a sobriety checkpoint. First, the checkpoint must be safe: it must be well lit, provide warning signals, and the traffic volume must be appropriate (no risk of danger - a sobriety check point on the 405 fwy is probably not wise). Police officers must be present in official uniform to legitimize the checkpoint (indicia of official nature of business). Also, since the stated purpose of checkpoints is to deter drunk drivers, the location must have high DUI activity.
Requirements: Length and Nature of Detention.
As mentioned in Step 2, law enforcement is permitted to briefly detain you in order to determine whether you are DUI by looking for signs of intoxication, such as odor of alcohol, slurred speech, bloodshot eyes, or open containers.
Requirements: Advance Publicity
Advance publicity is necessary to reduce the intrusiveness of the checkpoint and increase its deterrent effect. After all, the purpose of a checkpoint is to "deter" drunk drivers (and not "arrest" them), right?
Requirement: Drivers Must Have an Opportunity to Leave if They Do Not Wish to Stop.
This may come as a complete surprise to you, but you actually have the right NOT to participate in a sobriety checkpoint. In fact, you may not be stopped and detained merely because you attempted to avoid the checkpoint. This is why it is also required that law enforcement post signs warning you that a checkpoint lies ahead. However, if you commit a vehicle code violation or display obvious signs of intoxication, there is adequate probable cause to pull you over. In other words, avoid the checkpoint if you can do it without commiting a V.C. violation.
So What Should You Do?
If you find yourself at a checkpoint that you do not want to be a part of, know this: You do not have to be a part of it! However, if your checkpoint is anything like the one I experienced today (where there was NO warning sign, NO opportunity to leave, and NO discernably neutral method of determining what car was stopped), you may have no choice, you may be questioned, and you may even be pulled aside for further investigation. Remember, you have the right to be silent and the right NOT to incriminate yourself. Field sobriety tests are tools used to incriminate you; do not participate.
If You Are Arrested ...
Not all is lost. Contact an attorney immediately! Remember all that talk above about "strict requirements"? If law enforcement did not strictly follow the proper procedures in conducting the checkpoint, your case could potentially be dismissed! You can snatch victory from the jaws of defeat!