On every road can be a truck on every moment, if you are on a parking or even on the side of the road there can't be trucks, but some people just spawn on the road.
My opinion is that you can show some respect to the other trucks and don't spawn right in front of their truck but spawn on a parking and if you are not you go to SP and move it there to a safe place. Imagine you have a 2000km load and the last 50km some guy spawns in front of you and you get 70% damage...