
Originally Posted by
SloMo26
According to the CA Vehicle Code:
CVC 670. A "vehicle" is a device by which any person or property may be propelled, moved, or drawn upon a highway, excepting a device moved exclusively by human power or used exclusively upon stationary rails or tracks.
CVC 23152. (a) It is unlawful for any person who is under the influence of any alcoholic beverage or drug, or under the combined influence of any alcoholic beverage and drug, to drive a vehicle. There is no stipulation that one must be driving on a road, highway etc.
So yes in the letter of the law you can be DUI on a horse. Whether or not you really upset the officer enough to take you jail for this, is a whole different story.