A limiting plate of a road paver is detachably attached to a traverse or to a chassis of the road paver to increase the basic working width. The limiting plate is arranged with variable spacing to a subgrade. In order to prevent a mix from flowing forwards in a direction of travel and at the same time improve the efficiency of a screw conveyor, in which a geometrically defined screw trough is formed, a limiting plate extension is arranged on the limiting plate so that it can be adjusted, particularly in the direction of the subgrade.