The safety margin aims to provide enough distance sideways when driving by for instance parked cars, pedestrians or cyclists. Someone in a parked car can suddenly open the door and pedestrians/cyclists can suddenly turn without looking or even fall or slip, so it’s important that you drive with a satefy margin. The margin/distance itself varies from situation to situation, for example when you pass parked cars, you can have 1 meter between the parked cars and your car, when driving on a country road at a higher speed when passing by a cyclist you can have a few extra meters sideways whileyou drive past the cyclist.