Car parks of administrative and multi-functional buildings are used by office tenants and their visitors. Tenants usually have reserved zones in lower floors and the system observes the length of transit or presence of tenants in the zone intended for the public. It is best to have interconnection of access systems for the building and car park at least at the level of data carriers, to allow the tenant to use the same card for car parks and door lock readers. Another required feature of car parking system for these application is counting of cars present in the car park for different groups, as the tenant companies usually own more cards then parking boxes. Systems support validation of short-term tickets, i.e. reduction or cancellation of the parking price for visitors of selected tenants. The system provides the car park operator with a survey of the quantity of granted discounts.