What must you do to avoid soiling the roadway?

You chose the correct answers. To prevent soiling the roadway when leaving a field, it is required by German traffic rules to remove loose earth from your tires and clean any working equipment before entering public roads. This helps to avoid creating hazards for other road users, such as slippery or dirty streets. The rule about only using truck tractors with twin tyres when it rains is not a legal requirement and does not address preventing dirt on the roadway. Always ensure your vehicle and equipment are clean before leaving unpaved areas to keep the roads safe for everyone.