The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, for dated reference documents, only the version corresponding to the date applies to this document; for undated reference documents, the latest version (including all amendments) applies to this document. GA/T414 Road Traffic Hazard Warning Light GA/T484 LED Road Traffic Induction Variable Message Sign GA/T995-2020 Technical Specifications for Video Evidence Collection Equipment for Road Traffic Safety Violations