It sounds counterproductive for police to announce where and when sobriety checkpoints take place. Drivers with questionable blood alcohol content levels may hear about the location and time and simply take a different route.
According to the Connecticut State Police Administration and Operations Manual, there is no option to keep quiet about sobriety checkpoint details. In fact, the manual states the press must be notified at least three days before the drunk-driving checkpoint is set up. This may surprise you -- sobriety checkpoints are carefully orchestrated operations.
Locations for checkpoints are not random. Operations are set up along "bad" stretches of road, where a significant number of accidents have taken places or citations have been handed out. Great care is taken to make sure the checkpoints are clearly marked and officers perform duties in a specific way.
What's the big deal? A 1990 U.S. Supreme Court ruling stated sobriety checkpoints were a violation of search and seizure protections guaranteed under the Fourth Amendment. However, the majority of justices felt removing drunk drivers from the road was beneficial enough to make an exception for vehicle "seizures" during forced stops at checkpoints.
In a 1996 Connecticut decision, an appeals court affirmed sobriety checkpoints were not violations of the state's constitution. In both cases, the key to keeping sobriety checkpoints legal was conducting the operations in a "reasonable manner."
These decisions are part of the reason vehicles are stopped in a consistent way at checkpoints, like stops for every fifth, seventh or tenth car. Using random searches, officers avoid targeting any particular drivers. The sobriety checks also must not place any undue time constraints upon motorists.
According to Mothers Against Drunk Driving, making arrests is not the goal of sobriety checkpoints. The checkpoints are mainly set up to discourage DUIs. Questions about the legality of sobriety checkpoints can be answered by a criminal defense attorney.
Source: MADD, "Sobriety Checkpoint FAQs" Dec. 01, 2014