Why should you brake hard now?

You are correct to choose braking hard because of the car. In German traffic rules, when a vehicle suddenly appears or behaves unpredictably—such as a car entering the road unexpectedly—you must be prepared to stop or slow down quickly to avoid a collision. The priority is to react immediately to the most immediate danger, which in this case is the car entering or crossing your path.

Slowing down early and braking firmly helps you maintain control and avoid accidents. Although trucks and tractors are large obstacles, if they are further away or moving steadily, the immediate risk from the car takes precedence. Always observe the whole traffic situation and react to the highest immediate risk first.