The short answer to this question is that sometimes it is possible to get a citation for driving under the influence (DUI) on a horse or a bicycle in the United States. This varies widely from state to state, however, depending on local laws and how a state defines a “vehicle.” As a general rule, it is better to be safe rather than sorry, and people should avoid riding or cycling if they have been consuming alcohol. Depending on regional laws, a DUI on a horse or bicycle can result in hefty fines and the loss of a driver's license.
DUI laws always apply to all motor vehicles, such as cars, motorcycles, and scooters. In some states, someone who gets a DUI while riding a horse can challenge it, arguing that a horse is not a motor vehicle. If the definition of a “vehicle” is sufficiently ambiguous, the court may not uphold the challenge, but if the term is specifically something with a motor, a DUI on a horse will be thrown out of court. The same goes for a bicycle, since a bicycle lacks a motor.
A state or region may choose to create laws specifically targeting drunk riders and cyclists, however. In such cases, it is entirely possible to get a DUI on a horse or bicycle, although the punishments may be slightly different than those in a motor vehicle. In a region where a citing officer knows that riding a horse or bicycle after drinking is not illegal, another type of citation may be issued. For example, a drunk cyclist may be charged with reckless conduct, public intoxication, or disturbing the peace.
While the idea of a DUI on a horse may seem silly, the main concern from a law enforcement point of view is public safety. Someone riding a horse or bicycle while intoxicated could potentially be a risk to others. Drivers, for example, might get in an accident because of the erratic riding pattern of the drunk individual. In the case of a horse, animal endangerment is also an issue. Several states have documented cases in which a horse died or was severely injured as a result of an intoxicated rider.
The procedure for citing and punishing a DUI on a horse or bicycle is usually the same for that in a motor vehicle. A law enforcement officer stops the rider or cyclist because the officer suspects that the rider may be under the influence. If a test such as a breathalyser indicates that the rider is intoxicated, the officer will issue a citation. In many states, the lawbreaker's license will be immediately revoked, and he or she will have to go to court to get it back. While in court, fines and/or community service may be imposed.