Even if there is no speed limit, there is a guideline speed of 130 kmh and the right-hand driving rule. If the rules are adhered to, you only overtake in one of the left lanes (whereby you must first check whether the lane is free) and then back again. It is not a big problem if you are overtaken with a speed difference of 200 kmh. Of course, the speed must be selected according to the traffic situation, which means that you are only on the road at high speeds when the highway is clear.