The side object system can be used to add props like guard rails and lampposts to roads.
However, the side object system is essentially a tool by itself. Side objects can be added to a scene without roads being involved. This can be done by creating a new object from the seconbd tab from the Left and by marking is as a "Side Object". After adding markers the side object can be activated.
More efficient is to create a new "Road" type:
General Settings > Road Types > Add New Road Type
Mark this road type as "Side Object":
General Settings > Road Types > Is Side Object
And auto activate the side object(s) for this "road" type:
General Settings > Road Types > Active Side Objects
The new Powerline preset is now available in the "Add New Road / Object" tab
