The invention relates to a roof box arrangement (1) for mounting on a vehicle (26), preferably a passenger car, which roof box arrangement (1) has a container comprising an under part (2) and an upper part (3), in conjunction with which the roof box arrangement (1) has at least one open position for loading and unloading and one closed position for the storage of objects. The roof box arrangement (1) comprises a hoisting device (4) capable of being positioned internally within the container, which device is mounted in such a way as to be capable of being caused to pivot to either side relative to the container. The hoisting device (4) comprises a holder (6) intended for engagement with an object, which holder, when the roof box arrangement (1) is in the open position and the hoisting arrangement (4) is in an outwardly-pivoted position, is capable of being lowered and raised, in conjunction with which lowering and hoisting of the object to either side of the roof box arrangement (1) is permitted. The invention also relates to a load system to permit the loading and unloading of a collapsible wheelchair (15) into and from a roof box arrangement (1).