(6) Any defect, lack of repair or lack of sufficient railing in any highway, townway, sidewalk, parking area, causeway, bridge, airport runway or taxiway, including appurtenances necessary for the control of such ways including but not limited to street signs, traffic lights and controls, parking meters and guardrails.
Paragraphs (1) to (6) of this subsection to which immunity applies are cited as examples and shall not be interpreted to limit the general immunity provided by this section.