The ADR (Accord européen sur le transport des Marchandises Dangereuses par Route) is a European document concerning the international shipment of dangerous cargo by road. It sets out the rules and requirements for transporting hazardous cargo by road in Europe. According to the ADR, dangerous cargo is classified into nine classes based on their properties and the type of hazard they pose:ExplosivesGasesFlammable liquidsFlammable solidsOxidizing substances and organic peroxidesToxic and infectious substancesRadioactive materialCorrosivesMiscellaneous hazardous cargoEach class is further divided into subclasses and divisions based on the specific characteristics of the dangerous cargo. The ADR includes detailed descriptions and criteria for each class and subclass of hazardous cargo and specific requirements for their packaging, labelling, and handling during transportation.