In California, sobriety checkpoints set up by law enforcement began in the 1980s, shortly after an opinion by the California Attorney General in 1984. At this time, guidelines established rules to make sure the roadblocks passed constitutional muster and adhered to principles consistent with state and Federal constitutions. 

An article by Patch.com relates that law enforcement chooses the location of checkpoints based on the frequency of DUI arrests and on accident statistics. The checkpoints are not synonymous with alcohol use. Law enforcement investigates any form of impaired driving whether it be alcohol, prescription drugs or recreational drugs such as marijuana. Officers also check to ensure licensing for the vehicle and the driver are legal and current. An arrest for a DUI charge continues to cost impaired drivers a substantial amount of money. Total expenses for a DUI charge could approach $13,000 and include fines, fees, increased insurance premiums, license suspensions and DUI classes. Jail time is also a possibility. While the public might hear about the time and date of an upcoming checkpoint, the exact location is typically not disclosed. 

An article in the Merced Sun Star reveals some more information on sobriety checkpoints. More impaired driving is likely to occur during the holiday season from late December through early January. This period of high activity coincides with increased checkpoints in some jurisdictions. The use of checkpoints is often in coordination with national campaigns such as Drive Sober or Get Pulled Over. A grant from the California Safety Office through the National Highway Traffic Safety Administration provides some funding for the checkpoints. Click here to learn more about a DUI stop in California.