When must attachments have additional lighting systems?

The answer you provided is indeed correct because it encompasses all necessary conditions under which attachments must have additional lighting systems according to German traffic regulations.

1. If the attachment blocks the vehicle's own lighting system, additional lights are required to ensure visibility and safety on the road. This rule is in place to prevent decreased visibility that could lead to accidents.

2. When an attachment projects more than 40 cm laterally beyond the vehicle's front and rear position lamps, it can pose a risk to other road users. Additional lighting helps to clearly indicate the presence and dimensions of the vehicle and attachment, reducing the risk of collisions.

3. If the attachment projects more than 1 meter beyond the vehicle's retro-reflectors, additional lighting systems ensure that the rear is visible to other drivers, especially in adverse conditions or at night.

By adhering to these regulations, road safety is improved for all users, enabling better visibility and communication on the road.