A truck uses all of its lane space, do not travel right on the centre line, use the road width available, to give you space between opposing traffic.
If stopped or broken down, where possible park well clear of the roadway. 10 centimetres past the fog line (the unbroken line on the left) is not safe for you or your car.
Use hazard lights and ensure headlights are dipped or switched to parking lights at night, to be able to be seen safely.
Safety triangles can be a worthwhile investment.