docs: @Override
  	@Pure
  	protected Rectangle2d calcBounds() {
  		final Rectangle2d rect = new Rectangle2d();
  		boolean first = true;
  		Rectangle2d rs;
  		for (final RoadSegment segment : getRoadSegments()) {
  			rs = segment.getBoundingBox();
  			if (rs != null && !rs.isEmpty()) {
  				if (first) {
  					first = false;
  					rect.set(rs);
  				} else {
  					rect.setUnion(rs);
  				}
  			}
  		}
  		return first ? null : rect;
  	}