Do sobriety checkpoints really deter drunk drivers?

Last week, the Columbia Police Department employed sobriety checkpoints and saturation patrols in an effort to stop Missouri drivers from driving while intoxicated. These types of checkpoints involve a roadblock, where officers will stop vehicles is a prescribed order, such as every third car, and ask the driver some questions.

During this questioning, the officer will be observing the driver for signs of intoxication or impairment, such as the smell of alcohol, slurred speech or blood-shot eyes. If they suspect that a driver is impaired, they may then ask the driver to exit the vehicle and perform some field sobriety tests.

If those tests confirm their suspicion, they may ask if they can take a blood sample to determine the driver’s blood alcohol content at that time. They will often have a judge or magistrate on call, in order to obtain search warrants for blood draws if the suspect is uncooperative.

Sobriety checkpoints have been permitted by the U.S. Supreme Court, despite being a technical violation of the Fourth Amendment, due to the grave risk of harm and large number of deaths attributed to drunk drivers.

But sobriety checkpoints have another problem. They are not very effective. Because they stop only the traffic passing the checkpoint location, they typically only result in a very low, often single-digit arrest percentages.

Law enforcement argue they discourage drivers from driving drunk, but because they have to be announced in advance and use a great number of resources, it is questionable whether they really provide any greater reduction in the number of drunk drivers on the road than merely having the officers patrolling for actual impaired drivers on the road.

Source: columbiatribune.com, “Columbia police plan DWI crackdown,” August 4, 2015