In a self-propelling road milling machine (1), particularly a (recycler or) cold-milling machine, comprising a machine frame (4) carried by a track assemblies (2,3) via lifting columns (12,13), a milling roll (6) supported on the machine frame (4) for treatment of a ground or traffic surface (8), height-adjustable side plates (10) for edge protection, arranged to rest on the ground or traffic surface (8) to be treated, a height-adjustable stripping means (14) arranged in the moving direction behind the milling roll (6) and adapted to be lowered, during operation, into the milling track (17) generated by the milling roll (6), and a control means (23) for controlling the milling depth of the milling roller (6), it is provided that at least one measuring means (16) is operative to detect the lifting, caused by the current milling depth, of a first sensor means resting on the ground or traffic surface (8), and / or the lowering of the stripping means (14) or a second sensor means onto the surface of the milling track (17), the control means (23) obtaining the current milling depth at the level of the stripping means (14) of the milling roller (6) or of the second sensor means from the measurement values of the at least one measuring means (16).