A vehicle with a cargo bed comprises an adapter element arranged in a movable manner along the cargo bed. A support element for at least one functional element is detachably fixed on the adapter element. A guide system for the adapter element comprises at least two parallel guide rails. The adapter element comprises at least two guide elements which engage in the guide rails. At least one guide rail comprises a retaining bead laterally projecting into a guide groove of the guide rail. At least one guide element fixed to the adapter element engages behind the retaining bead, such that a lifting of the adapter element is prevented by the guide rail. The adapter element comprises at least one braking device, which can be brought into operative connection with the cargo bed in order to prevent a displacement of the adapter element on the cargo bed.