link coupling the configuration as a pivot axis is less material intensive and therefore more cost effective in principle in the embodiment with a four link coupling in accordance with fig7 the side air guiding element 19 pivots away further from the outer edge and the hinge hinges 6 of the rear door 5 once the side air guiding element 19 has been unlocked it can be adjusted by hand as it is easy to grip in its lower region and furthermore no adjustment takes place against gravity the hinge 6 of the rear door 5 may be moved slightly forwards in respect of the rear door 5 i e positioned in the region of the vehicle structure 2 in the longitudinal direction x in front of the rear door 5 with this kind of design of the rear region of the truck 1 the pivoting action during the opening of the rear door 5 can be improved the roof air guiding element 9 is flexible or elastic in its external region 9 b so that in the basic position it does not prevent a subsequent pivoting out of the rear door 5 in accordance with fig5 and 6 in a forward direction for improved access to a loading space in front of the rear doors 5 and for the fixing of the rear door 5 to the side wall 3 the roof air guiding element 9 is deformed during this forward pivoting action of the rear door 5 and received between the rear door 5 and the side wall 3 in this case the external region 9 b which.