At the most basic level, a car free zone is a geographical area where motorised vehicles are not permitted – with the exception of emergency vehicles and, in some cases, delivery vehicles with special permits. In most car free zones, also other motorised vehicles (e.g motorcycles) are prohibited if their maximum speed exceeds a certain velocity; typically 20 km/h.

• If special permit vehicles with emission free engines are allowed into a car free zone, it is a Zero Emission Zone.
• If special permit vehicles with internal combustion engines (not considering emergency vehicles) are allowed into a car free zone it is not a Zero Emission Zone.
• If absolutely no vehicles (except emergency vehicles) are allowed into a car free zone it is not even a UVAR because a UVAR implies that certain vehicles, which meet certain regulations are allowed.