The state of California, like 37 other U.S. states, allows police to stop motorists at DUI checkpoints for evidence of drunk driving.
In recent years, however, the internet has made it more difficult for police to successfully operate these checkpoints. As soon as citizens realize where a DUI checkpoint has been erected, people start sending out the word to friends, neighbors, and family on social networking websites like Facebook and Twitter.
In California in 2009, over 1.8 million cars were stopped at DUI checkpoints throughout the state. Out of these 1.8 million stops, 5,000 drivers were arrested for drunk driving. This means that on average, only about 1 in every 200 stopped cars actually has a drunk driver at the wheel.
Some police departments and police chiefs believe that rolling patrols—in which police officers move along the roads looking for possible drunk drivers—are more effective. These patrols are more difficult for people to evade, because they aren't located in a single position.
Certainly, a higher percentage of traditional DUI traffic stops result in arrests than DUI checkpoint stops. What's more, checkpoint stops aren't focused on the people who are actually creating hazardous conditions on the road, the way that rolling patrols are. Instead of arresting dangerous people, many of the people arrested at DUI checkpoints are actually arrested because they didn't have their license or registration on them—which counts toward arrest totals even if the driver is later able to produce the required documentation.
Checkpoints take police resources away from patrolling other areas of town. Drunk drivers keep drinking and driving. They just simply avoid the DUI checkpoints.
Traditional police DUI patrols that look for classic signs of impaired driving, including swerving, low speeds, and inattentiveness, are substantially more effective than DUI patrols. They also do a better job of protecting the rights of the huge majority of Americans who are driving sober.