The management and assignment of parking zones is designed to provide a parking space to permit holders. However, uncontrolled access to parking areas and unexpected parking demand make it impossible to guarantee a parking space in the permit holder's assigned zone. Staff and students are generally assigned to specific parking areas referred to as zones. Parking zones are color-coded with respect to their price and numbered with respect to the specific parking zone assignment of each permit holder. Permit holders may park in their assigned zone as reflected by the combination of color and number on their permit and corresponding sign. Exception: Green permit holders may park in their numerically assigned green zone or in any red zone.