A system for regulating access to a resource by a plurality of users is provided. The system comprises: a plurality of portable access keys, each being provided to one of the users and having an associated variable access parameter; an access barrier, having an open state allowing passage through and a closed state denying access to the resource, and defining an access queue; a sensor that determines an access queue characteristic related to a number of users in the access queue; a controller, which sets an access criterion based on the determined access queue characteristic; and a detector, located at the access barrier and which determines the variable access parameter of a portable access key when it is brought into the vicinity of the detector. The controller sets the access barrier in its open state if the variable access parameter determined by the detector meets the access criterion.