While it is physically possible to ride a horse while intoxicated, the legality of doing so varies depending on local laws and regulations. Different states interpret the legal status of a horse; state law in Michigan as of 2014, for example, classifies horse traffic like automobiles.
In Michigan, local intoxicated driving laws are worded so they only apply to drivers of motor vehicles. Being drunk on a horse in Michigan does not result in a DUI. However, the rider can still be cited for any violations that are committed, such as public intoxication laws. In Alabama in 2007, a woman was arrested for DUI after ramming a police car with the horse she was riding.