docs: @SuppressWarnings("unchecked")
  	@Pure
  	public Tree<RoadPolyline, ?> getInternalTree() {
  		if (this.roadSegments instanceof GISTreeSet<?, ?>) {
  			return ((GISTreeSet<RoadPolyline, ?>) this.roadSegments).getTree();
  		}
  		return null;
  	}