Milwaukee County Sheriff David Clarke's "Operation Unlucky Shamrock" found 38 alleged drunk drivers didn't have the "Luck o' the Irish" with them on St. Patrick's Day.

Sheriff's Deputies and the Wisconsin State Patrol combined to arrest those 38 between 2:00 p.m. Monday and 5:00 a.m. Tuesday morning.

That's a dramatic increase from the 21 who got arrested in 2007.

A release from the Sheriff's Department says it doubled its fleet of patrol units on area freeways that were devoted to targeting drunk drivers.

Sheriffs say it will continue its specialized drunk driving patrols on the freeway system.

"They are trained in targeting drunk drivers. They are looking for certain signs," said Milwaukee County Sheriff's Spokesperson Aisha Barkow.

"They have a lot of experience in detecting these type of drivers."

She explains that it's not an attempt to simply raise arrests numbers, but to "go out and facilitate the safe movement of traffic on the highway system.

"Drunk driving is something the sheriff has repeated is unacceptable behavior. It's irresponsible and it's very dangerous. It puts the public at great risk. This definitely is a behavior that we have zero tolerance for."