Abstract: The invention relates to a safety system on track guidance lines for optionally track-guidable or road-going vehicles with pivotable feeler rollers. To avoid accidents which may be caused by travelling on track guidance lines with feeler rollers not extended or only incompletely extended, the invention provides for there to be a switch, which can be operated by the feeler rollers, to be arranged on each of the two transverse guide barriers, approximately opposite each other on the same level as the feeler rollers of the vehicle, at the beginning of the track guidance line. These switches, if operated together, switch via a control unit an optical display device, located downstream of the switches in the direction of travel of the vehicle, and normally indicating a block signal, to "clear line".