When are you not allowed to drive a motorized bicycle on public roads?

The correct combination of choices indicates the circumstances under which you cannot operate a motorized bicycle on public roads.

Firstly, driving without motor vehicle liability insurance is a serious legal violation in Germany. This insurance is mandatory for all motorized vehicles to ensure that third parties are compensated in case of an accident. Without it, you are not permitted to drive.

Secondly, a motorized bicycle must be roadworthy, meaning it should be in a condition that complies with safety standards. If it is not roadworthy, it poses a risk to both the rider and others on the road, making it illegal to operate.

The third option, not paying motor vehicle tax, is relevant but not included in the answers. While not paying this tax can have legal repercussions, it does not directly prevent one from riding a motorized bicycle like the other two options.

Thus, the combination of options 1 and 2 is essential for ensuring safety and compliance with the law.