When is it illegal to operate a motor vehicle in Maryland?

Operating a motor vehicle in Maryland is illegal when there is an open container of alcohol present in the passenger area. This law is designed to promote safer driving by discouraging the presence of alcohol in vehicles, which could increase the temptation for drivers and passengers to consume alcohol while the vehicle is in motion. Maryland's open container law specifically prohibits the driver from having an open alcoholic beverage anywhere in the passenger area, as this can lead to impaired driving and pose a significant safety risk.

While the other situations mentioned might involve restrictions or dangers (for instance, drivers under 21 face more stringent regulations regarding alcohol consumption, and adverse weather conditions can lead to unsafe driving), they do not carry an explicit prohibition like the open container law does. Therefore, the presence of an open container in the passenger area is the definitive reason that makes operating a vehicle illegal in this context.