When emerging from a minor road into the major road, we should not cause any vehicle who has priority to slow down, stop or change direction.

When emerging from a minor road into the major road, one way to check if you can emerge safely is to think as a pedestrian and see if you would make the decision to cross the road as a pedestrian, if you would then as far as not causing the vehicle to slow down, stop or change direction it should be safe to go.