This St. Patrick?s Day weekend, the AAA Mid-Atlantic, the Maryland Department of Transportation?s State Highway Administration, Yellow Cab and the Downtown Partnership of Baltimore will be working together to provide free taxicab rides to potentially impaired drivers. As part of a combined effort called Tipsy? Taxi! Campaign, cab rides under $50 will be provided for free by Yellow Cab for anyone 21 years of age or older who has been drinking at a bar or restaurant in Baltimore City tonight at 8 p.m. until Saturday at 4 a.m., and then again from Saturday at 4 p.m. until Sunday at 4 a.m.