What can be the consequences if the tow-bar of a towing coupling has longitudinal play?

In this case, your selection of options 1 and 2 is correct because they highlight the potential structural dangers that can arise from having longitudinal play in the tow-bar of a towing coupling.

The reason why these consequences are critical pertains to vehicle safety standards set by the German traffic regulations. Option 1 emphasizes the risk of cracks forming in the cross member where the towing coupling is attached, which can compromise the integrity of the towing setup. Option 2 addresses the risk of the towing coupling detaching entirely, posing a significant hazard not only to the vehicle and its occupants but also to other road users.

Option 3, while it relates to vehicle stress, is not a direct consequence of the longitudinal play in the tow-bar itself. Understanding these consequences is crucial as they underscore the importance of maintaining proper equipment on vehicles to ensure safe operation in compliance with traffic safety regulations in Germany. Regular inspections and maintenance are essential to prevent failures that can arise from overlooked issues such as play in the towing coupling.