Sobriety checkpoints are road stops set up by law enforcement to check drivers for driving while under the influence of alcohol.
To avoid rights violations, law enforcement must announce when and where they will take place. Many people question if the checkpoints are effective because of this.
One of the reasons why public perception is checkpoints are not useful is because they do not understand the main reason for having them. The goal is not to arrest and remove drunk drivers from the road. The goal is to deter drunk driving because people know officers are looking for them and actively making arrests if they find them. It is about deterrence rather than just gathering up people who are violating the law.
When looking at the real goal, these checkpoints are effective. When states hold them regularly, they do help reduce the number of drunk drivers on the roads, which is beneficial to everyone and saves lives. They help to make people rethink getting behind the wheel and encourage alternatives, such as calling a cab or having a sober driver.
Even more interesting, the more publicized an area makes checkpoints, the more effective they are. While officers may not make a lot of arrests, the public knowing about the checkpoint and that they happen often reduces the number of drivers on the road who are under the influence. It causes an overall benefit that may not be directly obvious in data from the actual checkpoint.