docs: @Pure
  	public Direction1D getSegmentDirectionAt(int index) {
  		final RoadSegment sgmt = get(index);
  		assert sgmt != null;
  		final RoadConnection conn = getStartingPointFor(index);
  		assert conn != null;
  		if (conn.equals(sgmt.getBeginPoint())) {
  			return Direction1D.SEGMENT_DIRECTION;
  		}
  		assert conn.equals(sgmt.getEndPoint());
  		return Direction1D.REVERTED_DIRECTION;
  	}