Final answer:
A driver cannot drive a motor vehicle if they do not have a valid driver's license, are under the influence of alcohol or drugs, or are not trained to drive. Not owning a vehicle does not directly prevent someone from driving, as they could rent or borrow one.
Step-by-step explanation:
A driver cannot drive a motor vehicle for several reasons, which may include: 1) Not having a valid driver's license, 2) Being under the influence of alcohol or drugs, and 3) Not being trained to drive a motor vehicle. Each of these conditions prevents someone from legally or safely operating a motor vehicle. Not having a motor vehicle of their own does not necessarily prevent someone from driving; they could potentially rent or borrow a vehicle. However, lack of a valid driver's license, training, or sobriety directly impacts one's legal ability or physical capacity to drive.
Governments set age and skill requirements for licensing to ensure the safety of drivers and the public. This involves passing knowledge and skills tests and usually requires a minimum age. Alcohol and drug use impair driving abilities and are prohibited while driving, as they significantly increase the risk of accidents. Being trained to drive ensures that the person knows how to operate a vehicle safely and is aware of traffic laws.