What is the purpose of orange placarding and signage?
Understanding ADR obligations

Placarding and signposting will enable emergency services to identify hazardous materials from a distance in the event of an accident, without having to expose themselves to the corresponding risks.

Placards must be affixed to the outside walls of containers and vehicles in accordance with ADR 5.3.1, "Placarding", to indicate the danger presented by the load. They correspond to the labels prescribed in column (5) and, where applicable, column (6) of Table A "Dangerous goods list" for the dangerous goods contained in the container or vehicle, and must comply with the specifications of 5.3.1.7 "Characteristics of placards".

Example: For goods that could pose a risk to the environment, a "fish/dead tree" plate must be affixed to the rear and sides of the vehicle.

Rapid identification of transported materials by means...