I can't filter the child view based on a value from the parent view
You should be able to accomplish this with one view.  I don't think views field view is necessary.
Add a view that shows Users
In the Filter Criteria section filter it by role (trucker).
Under Advanced use the Relationships dropdown to add the relationship Content Authored.
In the Fields section add a field to show whatever field of the trucks content type you want to show for each trucker (e.g. truck name).  You could also use title.  This field setting will use the &quot;node&quot; relationship which is available as a result of adding Content Authored in the relationships dropdown in the advanced section.
If you do use title instead of something like truck name, or any field that appears in multiple content types, in the Filter Criteria section be sure to add a &quot;content type&quot; filter in order to restrict results to the trucks content type.
Format the results as you like (e.g. table, etc.).