The Utah police agencies used to do "administrative checkpoints" to pull people over for no reason and then check them for alcohol.  The problem is that that charges can be challenged because there are so many rules the police must follow to make them constitutional.  So the police answer this by doing Saturation Patrols.  The highlights of this technique are as follows:

• Citizens get pulled over for a claimed legal, but usually minor reason.  (i.e. burned out license plate light, failure to signal for 2-3 seconds before turning, not coming to a complete stop, or if nothing else works, tell the driver the officer’s computer shows the car is not insured when it actually does).
• The police usually get several agencies involved like the Utah Highway Patrol, Salt Lake City Police Department, and the Salt Lake County Sheriff’s office.
• The patrol occurs heavily around the time the bars are in full force and the patrol occurs around these bars.

Here is a recent story where 35 officers got together, pulled over 774 citizens, and arrested one person for DUI.

774 PEOPLE PULLED OVER!  If an officer wants to pull you over, I’m sure the officer can find a reason.  What a waste of taxpayer money in an effort to effect the witch hunt.

Police pull over 774 vehicles in DUI patrol
Published: Sunday, Oct. 28, 2007 12:23 a.m. MDT

More than 35 officers from six different police agencies conducted a DUI saturation patrol on Friday, pulling over 774 vehicles.

The patrol was conducted in the area of 6500 South and Redwood Road from 10:30 p.m. to 2 a.m. on Saturday morning.

According to the Utah Highway Patrol, officers made one DUI arrest with 14 other drug- and alcohol-related arrests, including minors in possession of alcohol. Four vehicles were impounded and 33 other drivers were either given citations or warnings.

The saturation patrol took place at a time when many are attending Halloween holiday parties.