Being stopped as part of DUI/Sobriety Checkpoint is terrifying. People are often unfamiliar with the procedures and don’t know what to expect. This content demystifies DUI checkpoints by explaining how they are administered and how to defend against DUI charges stemming from a checkpoint stop.
Ingersoll v. Palmer (1987) 43 Cal.3d 1321 lists eight factors that must be met by the police when performing a DUI checkpoint. The Ingersoll case can be found here:
The eight factors laid out in Ingersoll are:
While the above factors may seem broad and confusing, DUI checkpoint law is pretty straightforward. It basically boils down to one question: Was the checkpoint set up and enforced in a fair and impartial way?
DUI checkpoint investigations are similar to standard DUI investigations. When administered correctly, the police will have signs posted ahead of the checkpoint and an outlet that allows you to avoid entering the checkpoint. You may not even be stopped. If stopped, the officer will ask questions to see if you are intoxicated. You will then be sent on your way or directed to a pre-planned area for more questioning and field sobriety tests. The investigation then operates like a standard DUI investigation.
A checkpoint may be avoided so long as the driver does not break any law or exhibit signs of intoxication in doing so. 
DUI checkpoints can be challenged in criminal court, as well as at your DMV hearing. Most of the standard DUI defenses also apply in the DUI checkpoint context. However, a subpoena requesting the “DUI Checkpoint Packet” must be sent to the arresting agency when a DUI checkpoint stop is involved. This packet describes how the checkpoint was set up and administered. Reading through the packet allows a skilled attorney to evaluate whether the constitutional requirements have been met, or whether a challenge should be made. Also, the recollection of the person charged with a DUI or any witnesses often is helpful in determining whether the requirements have been met.
If a DUI checkpoint is found to be unconstitutional, your case will be dismissed and your administrative suspension by the DMV will be set aside.