You are driving on a very narrow road and can see 50 m ahead. What must be your maximum stopping distance?

On narrow roads you must always be able to stop within the distance you can see to be clear. The rule of thumb in German traffic law is “drive only as fast as you can stop within half your visible distance” when the road is so narrow that two vehicles cannot safely pass and you may have to yield or stop for oncoming traffic at any time.

If you can see 50 m ahead, you therefore must choose a speed so that your stopping distance (reaction distance plus braking distance) is at most 25 m. That way, even if an oncoming vehicle appears in the visible section, both vehicles can stop in time without a collision.

For similar questions: first check the visible distance, then take half of it as the maximum allowed stopping distance on a very narrow road.