What can be caused if the road surface suddenly becomes worse?

The correct combination of answers addresses the various dangers associated with a sudden deterioration of road conditions.

1. **Danger of sliding and skidding**: Poor road surfaces, such as those with ice, rain, or loose gravel, significantly increase the risk of loss of traction, leading to sliding or skidding. This is a crucial factor in maintaining road safety as per German traffic regulations.

2. **Changes in tyre noise**: As road conditions worsen, the interaction between the tyres and the road changes, which can lead to a noticeable difference in the noise produced. This serves as a key indicator for drivers to adjust their driving style based on road surface conditions, highlighting the importance of being attentive to such changes.

The option that was not included, **longer reaction distance**, is also essential because deteriorated road conditions can impede braking and overall vehicle control. It emphasizes that drivers must anticipate that stopping distances may increase, thus requiring them to be more cautious and to allow more time to react to unexpected situations.

Understanding all these aspects helps ensure safer driving practices and adherence to safety regulations outlined in German traffic laws. Awareness of road conditions is crucial for preventing accidents and ensuring the safety of all road users.