Abstract: A system for marking a corner angle in a working area with the aid of light planes, wherein a straight, elongate guide is disposed on each respective side of a planar working surface in the working area. Each guide carries a carriage that can be moved to chosen positions alongs its guide. Each carriage carries a laser unit which is adapted to emit a light plane that intersects the working surface, as well as the light plane of the other laser unit, at a chosen angle. Each laser unit is adapted to maintain its light plane in a set orientation relative to the longitudinal axis of its associated guide, regardless of the position to which the carriage has been moved along said guide, and both laser units are adapted to be activated simultaneously for marking said corner angle.

Abstract: A method and an apparatus for determining the resiliency of a road surface include a vehicle (1) that is caused to move along the road surface (3) and that exerts a load on said surface with one wheel (2). A ball of plastic material (16) is shot onto the road surface (3) so as to adhere thereto in the movement path of two measuring arrangements (8, 9; 18, 19) which are separated in the direction of movement of the vehicle (1) and by means of which the vertical distance is measured between the upper side of the ball (16) adhering to the road surface (3) and a vehicle-carried reference in two positions along the vehicle. The distance between the reference and the measuring body can be established in several positions along the vehicle (1), for determining the deflection curve of the road surface.