ADR, or dangerous goods, is a type of goods that consist of substances and products, which can cause damage to health, the environment and people's property in case of an incident during transit. Therefore, this type of cargo has specifics during transportation, as well as requires special training of drivers and crew members. This type of cargo includes solvents, paints, fertilizers, adhesives, batteries, medical materials, chemicals, etc.

There are 9 hazard classes. Each class represents a group of substances combined according to the main method of exposure: explosion, flammability, radioactivity. Based on the hazard class of the cargo, the procedures and conditions for transportation, as well as the list of necessary documents, are determined.

ADR cargo hazard classes:

Hazard class 1. Explosives, objects and materials that can cause fire. This class also includes pyrotechnic products. This class has 6 subclasses.
Hazard class 2. Compressed and liquefied gases as well as dissolved ones. Toxic, flammable substances. This class has 3 subclasses.
Hazard class 3. Flammable liquids and their mixtures. Liquids containing solids or suspensions that emit flammable vapors.
Hazard class 4. Substances and materials that quickly ignite if there is a fire source nearby or due to friction or spontaneous chemical reactions. This hazard class includes 3 subclasses.
Hazard class 5. Oxidizing substances as well as peroxides that release oxygen, which contributes to rapid combustion. This class has 2 subclasses.
Hazard class 6. Poisons and infectious substances that, if handled incorrectly, cause death or severe poisoning. This class has 2 subclasses.
Hazard class 7. Radioactive substances from categories I–III.
Hazard class 8. Caustic and corrosive substances that can cause damage to skin, mucous membranes of the mouth and eyes, as well as to the respiratory system. This class includes 3 subclasses.
Hazard class 9. Dangerous substances and products, including substances hazardous to the environment. These are the substances that are not included in any of the previous classes, have little danger but require attention during transportation. This class has 2 hazard subclasses.

Transportation of dangerous goods can be carried out by road, sea, rail or air transport. Depending on the choice of transport, the features and conditions of the delivery as well as the mandatory requirements for the execution will differ.