A two-axle trailer with overrun brakes and fifth-wheel steering is parked on a slope. How must it be secured against rolling?

To secure a two-axle trailer with overrun brakes and fifth-wheel steering on a slope, it is essential to take comprehensive measures to prevent it from rolling. Engaging the parking brake is crucial, as it provides a primary means of holding the trailer in place when stationary. This is a standard safety requirement outlined in German traffic regulations.

Additionally, placing a wheel chock under a rear wheel is an effective way to provide supplemental security against rolling. Chocks are especially important in preventing any accidental movement when the parking brake alone might not suffice, particularly on inclines.

While supporting the forked draw-bar at the height of the coupling is less common as a standalone method, it can add an extra layer of safety. However, it is not primarily a means of securing against rolling but rather a way to ensure that the trailer is stable when attached to a vehicle.

Thus, the combination of both engaging the parking brake and using wheel chocks is the best practice for securing a trailer on a slope, as it addresses multiple aspects of stability and safety required under German traffic laws. Each measure acts cooperatively to provide maximum security, ensuring that the trailer remains stationary and does not pose a hazard to other road users.