Drunken drivers are warned not to test their luck this St. Patrick's Day as extra patrol officers take to the road to watch out for those who may have had a green beer too many before getting behind the wheel.

St. Patrick's Day is the second-deadliest holiday for alcohol-related deaths (the first is July 4th), according to the Minnesota Department of Public Safety. This St. Patrick's Day has the potential to be even more dangerous because it falls on a Saturday.

In 2007, the last time the holiday occurred on a Saturday, 2007, 527 Minnesota motorists were arrested for drunken driving, and the three traffic deaths that happened that day were all alcohol-related.

"We certainly expect to see a larger turnout," said Lt. Eric Roeske of the Minnesota State Patrol. Still, he said, "There really is no excuse to get behind the wheel if you've been drinking."

To deter possible drunken driving, law enforcement is using television, online and billboard ads along with posts on Facebook and Twitter. On Saturday night, arrest updates will be posted on digital billboards across the Twin Cities.

Metro Transit and MillerCoors have partnered to offer free rides on Twin Cities buses, light rail and Northstar commuter rail on Saturday night.

Revelers can ride free from 6 p.m. through the last scheduled trip on routes operated by Metro Transit, the Met Council and the Minnesota Valley Transit Authority. Metro Transit's phone center will extend its hours until 7 p.m. to help travelers. Call 612-373-3333.