You've heard about them, maybe even driven through one -- and tomorrow night Sacramento Police will have another DUI checkpoint. But the reason for the checkpoint may surprise you.

Chris Cochrane with the Office of Traffic Safety says the DUI checkpoints aren't designed to catch you driving drunk.

"It's actually for the deterrent effect of people driving through them, hearing about them from friends, reading about it in the paper," Cochrane said.

The Federal Transportation Fund gives California gets about $70 to $80 million dollars a year for this prevention program.

"Regular patrols are great at arresting people, but not so great at deterring crashes," he said.

DUI Checkpoints have been shown to lower the crash rate and the DUI-related fatality rate in the areas where they take place, Cochrane said.

Find out about DUI checkpoint locations, Free Cab Fridays, and other tips on the California Office of Traffic Safety Facebook page.