MADISON, Wis. (AP) – A new phone app is designed to help keep drunken drivers off the road.

The “Drive Sober” app launched by the state Department of Transportation allows motorists to estimate their blood alcohol content and select a designated driver. The app also has a function to find a safe ride home that uses the phone’s GPS to provide contacts for nearby taxi, mass transit and designated-driver services.

It also includes a simulation showing the physical effects of being drunk.

The department is touting the app in advance of the St. Patrick’s holiday weekend.

A free download of the app is available online at http://www.zeroinwisconsin.gov.