Upright or projecting signs or signals permanently installed directly on or in

Official title: {Upright or projecting signs or signals permanently installed directly on or in the roadway and designed to be depressed by rolling or other loads and then to return to normal position, e.g. collapsible or rockable stop signs, flexible vehicle-striking members for audible warning (E01F9/565, E01F13/10 take precedence)}

E01F9/602 (Upright or projecting signs or signals permanently installed directly on or in) appears on 24 US grants and 18 published applications in this corpus.