The question comes up frequently whether a DUI checkpoint must provide a sign to those approaching it. Put another way, must a sobriety checkpoint give advance warning to the driver and allow them an opportunity to turn out and avoid the operation if they desire? The U.S. Supreme Court specifically rejected a lower state court's finding in that case that a checkpoint is unreasonable if law enforcement fails to demonstrate that motorists are made aware of their option to make If-turns or turnoffs to avoid DUI checkpoints. The U.S, Supreme Court stated the lower court erred by misreading its precedent on what was an improper "subjective intrusion" that a checkpoint could make on an individual driver. A checkpoint's intrusion on motorists by causing "fear and surprise" in them is "not the natural fear of one who has been drinking over the prospect of being stopped at a sobriety checkpoint but, rather, the fear and surprise engendered in law-abiding motorists by the nature of the stop."
According to one Long Beach DUI Attorney, The U.S. Supreme Court observed: "The circumstances surrounding a checkpoint stop and search are far less intrusive than those attending a roving-patrol stop .... At traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers' authority, and he is much less likely to be frightened or annoyed by the intrusion.' [Citation]" Martinez-Fuerte, 428 U.S., at 558." (Sitz, supra, 496 U.S. at p. 452.) Nowhere in Sitz does the U.S. Supreme Court state that a turn off must be provided before the announcement of a DUI checkpoint. It only states that checkpoints cannot cause fear and surprise in drivers by randomly stopping vehicles without reasonable suspicion, something which the Fourth Amendment guarantees against. To be reasonable under the Fourth Amendment, the checkpoint must provide visible signs of the officers' authority, must be regular in routine and not arbitrary or random, and provide visible evidence that the stops are duly authorized and serve the public interest. (Sitz, supra, 496 U.S. at p. 453; Martinez-Fuerte, 428 U.S., at p. 559.) It is true that in Ingersoll, the California Supreme Court found that the checkpoint had a road sign placed sufficiently in advance of the checkpoint that motorists could choose to avoid the checkpoint. (Ingersoll. supra, 43 Cal.3d at p. 336.) However, the U.S. Supreme Court in Sitz subsequently rejected that same objection made by defendants in that case.
In many DUI prosecutions, there is substantial evidence that the DWI checkpoint provided indicia of its official nature. There are usually uniformed personnel manning the checkpoint. The lanes are typically divided with bright orange reflective cones. Police cars line the shoulder of the roadway and activated their flashing amber overhead lighting equipment. There are electronic construction-type sign at the beginning of the checkpoint area that are reflective orange in color, and bad light bulbs upon which is written "DL DUI checkpoint." Most Courts will conclude that there was sufficient notice announcing the checkpoint given to drivers in advance of the checkpoint location to permit motorists to turn aside and avoid the checkpoint under these circumstances. Most Judges will conclude that there is no constitutional requirement that a sign announcing the checkpoint be located prior to a turn off.