Saturation Patrols are specially trained two man Police teams that cruise the city specifically to locate and arrest intoxicated drivers. Typically there are several teams out at the same time.

Quote from the Newport Beach PD:  "The major value of checkpoints is their educational and deterrent influence on the motoring public,"

Interesting article, from the Orange County Register;
DUI checkpoints of dubious value, legality
http://www.ocregister.com/ocregister/opinion/abox/article_1393748.php

Mothers Against Drunk Driving (MADD) estimates that communities that consistently use sobriety checkpoints experience as much as 8 times the reduction in DUI incidence as communities that use roving patrols alone.

For the latest information on DUI checkpoints and statistics, and for general discussion, see the DUI blog at http://www.ocduiblog.com

Here's a few examples of the results of the DUI Checkpoint efforts:

The Irvine Police Department conducted a sobriety/driver’s license checkpoint during the evening hours on Saturday, December 17.   The checkpoint was located on Mac Arthur Blvd. at Douglas in the city of Irvine. Here are the results of that checkpoint:

Total vehicles stopped: 337
DUI arrests:   4
Other arrests:  9
Citations:  17
Vehicles Towed:  10

The Huntington Beach Police Department conducted a sobriety checkpoint on Saturday, June 10, 2006 from about 9:30 P.M. to 1:45 A.M.

More than 1300 vehicles passed through the checkpoint and about 400 vehicles were selected for screening. Of the 400 vehicles selected, five drivers were arrested for driving under the influence, eighteen were issued citations for driving without a license or for driving on a suspended license, and nineteen vehicles were impounded. Three people were cited for driving with an open container. Four others were arrested for possession of stolen property, possession of burglary tools, possession of marijuana, and for warrants.