Abstract: With this safety beading or ledge the drive of, for example, a driverless transport vehicle can be switched-off on collision with an obstacle, and can be switched-on again after removal of the obstacle. The safety beading or ledge mounted along a shock-absorbing or impact edge of the transport vehicle is provided for this purpose with a plurality of similar contact elements which are disposed in series and touch one another at contact points in an elastically deformable, pre-stressed tube. During collision with an obstacle and deformation of the safety beading or ledge the contact elements perform a rocking movement against one another, whereby contact is interrupted and the drive is switched-off. After removal of the obstacle the elasticity of the tube effects a return into the initial position, whereupon the contact points again touch and the drive is switched-on again.