How is a drug defined in the context of operating a vehicle under the influence?

In the context of operating a vehicle under the influence, a drug is defined as a substance that can impair the ability to operate a vehicle safely. This understanding encompasses not only illegal drugs but also legal substances, including prescription medications and over-the-counter drugs, that may affect a person's cognitive functions, motor skills, or overall judgment.

Impairment can occur regardless of the legality of the substance involved. Thus, if a driver consumes anything that negatively impacts their ability to drive—such as causing drowsiness, reduced reaction time, or altered perception—they are considered to be operating under the influence. This definition helps emphasize the importance of assessing one's fitness to drive based on their mental and physical capabilities rather than solely focusing on the legality of what they have ingested.