Why do the police have to announce DUI checkpoints in advance?

Many Rock Hill residents have probably had this thought: if DUI checkpoints are meant to catch people who are driving drunk, then why do local police departments announce when and where the checkpoint will occur? It seemingly defeats the purpose of the checkpoint, which one would expect to be a surprise, thus increasing the likelihood of catching offenders in the act.

In 1990, the U.S. Supreme Court made a ruling on a drunk driving case that would change DUI checkpoints forever. The ruling upheld the checkpoints as constitutional — however, the Supreme Court also said that the checkpoints had to be publicized to give citizens notice. Otherwise, the checkpoints would violate the Fourth Amendment: an illegal search and seizure, since the police would lack reasonable cause.

So here we are today, with DUI checkpoints that have to be announced well in advance of their enactment. The announcement has to include specifics regarding the location and time of the checkpoint. If the police hold up their end of the deal by posting the checkpoint details, any driver who is above the legal blood alcohol limit (0.08) and passes through the checkpoint will likely be given a one-way ticket to jail.

However, if the police do not uphold their responsibility and fail to announce the DUI checkpoint, any person who is arrested or accused of driving under the influence can have their case dismissed. The BAC results garnered from that checkpoint would be invalid, and the individual would likely have the charges against them dropped.

Source: Valley Independent Sentinel, “Why Do Police Announce DUI Checkpoints?,” Ethan Fry, Nov. 20, 2012

• To learn more about DUIs, please visit our Rock Hill drunk driving defense page.