Motor vehicle with support system for vehicle roof rails

The invention relates to a motor vehicle (1) with a roof rack carrier system (2), with vehicle-exterior railing rails (4,5) firmly attached to both longitudinal sides of a vehicle roof (3) and at least two carrier rails (6,7) which can be releasably connected in the vehicle transverse direction and spaced at their ends respectively with the railing rails (4,5), and with a vehicle-interior cargo space (9) with an at least in partial areas flat cargo space floor (10). According to the invention, receiving channels (11,12) adapted to the shape of the carrier rails (6,7) are recessed in the cargo space floor, into which carrier rails (6,7) removed from the railing rails (4,5) can be inserted in such a manner that they are integrated flush with the floor surface in the cargo space floor (10).