The sign you referred to is known as the "marking obligation for vehicles carrying hazardous materials." This traffic sign indicates that vehicles transporting hazardous materials must follow specific regulations while driving through a designated area.

According to German traffic laws, drivers of vehicles carrying dangerous goods are typically required to adhere to strict guidelines to ensure safety. This includes aspects like:

1. **Route Restrictions**: Certain routes may be off-limits for these vehicles to prevent accidents and protect residential or high-traffic areas.

2. **Additional Markings**: Vehicles must be marked with specific signs that indicate the type of hazardous material they are carrying, making it clear to other road users.

3. **Increased Safety Protocols**: These vehicles may need to follow slower speed limits and adhere to special driving regulations during certain times or in particular conditions.

Always ensure that you understand and comply with these regulations if you are driving a vehicle that falls under this category, as failing to do so can lead to serious consequences. If you have more questions regarding specific regulations or scenarios, feel free to ask!