You may have stumbled across (or driven through) a police barricade while leaving an outdoor festival or live sporting event. Called sobriety checkpoints, these barricades allow police officers to randomly stop as many or as few vehicles as they wish in an attempt to find and arrest individuals who are driving while intoxicated.

Although many law enforcement and activist groups have touted these sobriety checkpoints as instrumental in reducing the number of drunk driving fatalities, recent studies have led some to question their effectiveness:

Are sobriety checkpoints effective?

In the past, these types of checkpoints have been challenged under both state and federal constitutional law. All individuals are guaranteed a certain amount of privacy and relief from police intrusion in their personal property -- including vehicles. Therefore, in order for a sobriety checkpoint to be constitutionally permissible, it must meet certain notice requirements. 

In general, before a police checkpoint can be set up or enforced, public notice must be provided to all potentially affected individuals. This notice must also be posted in a highly visible manner at the checkpoint itself.

Because of the extent of notice that must be provided to those who could be detained at the checkpoint, many critics argue that the checkpoint loses the element of surprise -- and therefore its effectiveness. In fact, several studies have compared the arrest rate (per motorist detained) at these checkpoints with the arrest rate during general patrols, finding that patrols are significantly more effective at actually curbing drinking and driving. 

What should you do if you're stopped at a sobriety checkpoint?

If you're detained, be polite and cooperative with the officer's requests. Although you may feel that the checkpoint is a waste of your time, you're unlikely to accomplish much by expressing this thought. If you are asked to step out of the vehicle, do so -- but stay near your car. 

If you feel that you've been detained for an extensive length of time, you may ask the officer if you are free to leave. Unless you are under arrest, you are not obligated to remain at the checkpoint once the officer has completed his or her inspection of your vehicle. 

If you are placed under arrest as a result of the checkpoint inspection, your first phone call should be to an attorney. Your attorney may be able to challenge the constitutionality or implementation of the checkpoint -- and if a court finds that the entire checkpoint was conducted unlawfully, your case may be dismissed. For more help, you may need to speak to a DUI lawyer for information.