What Is ADR Transport

What Does ADR Stand For?

ADR derives from the original French title of the 1957 Geneva treaty: Accord relatif au transport international des marchandises Dangereuses par Route — A for Accord, D for Dangereuses, R for Route. The English name is the European Agreement concerning the International Carriage of Dangerous Goods by Road.

The active edition is ADR 2025, published as ECE/TRANS/352, Volumes I and II. ADR follows a biennial amendment cycle — the Working Party on the Transport of Dangerous Goods (WP.15) adopts changes that take effect on 1 January of odd-numbered years. ADR 2027 amendments were formally notified to contracting parties on 1 July 2026 and enter force on 1 January 2027 unless objections are lodged before 1 October 2026.

The treaty was originally drafted for movements crossing the territory of at least two contracting parties. All EU member states have since incorporated Annexes A and B into domestic law under Directive 2008/68/EC, making ADR requirements applicable to dangerous goods road transport within individual member states — not only at international borders. ADR Table A is the operational core of the agreement — the master list that assigns each classified substance its UN number, hazard class, packing group, and transport conditions, forming the classification reference used across European road freight compliance.

What Are the 9 ADR Hazard Classes?

ADR divides dangerous goods into 9 hazard classes — Class 1 through Class 9, with several internal sub-divisions — each carrying distinct packaging, labelling, vehicle marking, and documentation requirements.

• Class 1 — Explosives: commercial mining explosives, airbag inflators, ammunition, and pyrotechnic articles.
• Class 2 — Gases: propane, butane, compressed oxygen, aerosols, and toxic industrial gases — sub-classified as flammable, non-flammable, or toxic.
• Class 3 — Flammable liquids: petrol, diesel, alcohols, solvents, adhesives, and paint products. Class 3 is the largest ADR class by road freight volume across Europe — fuel distribution and chemical supply chains generate the bulk of Class 3 movements.
• Class 4.1 — Flammable solids: matches, metal powders, self-reactive substances, and desensitised explosives.
• Class 4.2 — Substances liable to spontaneous combustion: white phosphorus and certain vegetable oils that ignite without an external ignition source.
• Class 4.3 — Substances emitting flammable gas on contact with water: sodium metal, calcium carbide, and aluminium phosphide.
• Class 5.1 — Oxidising substances: hydrogen peroxide, ammonium nitrate-based fertilisers, and pool chlorine.
• Class 5.2 — Organic peroxides: used in plastics manufacturing and chemical synthesis, sub-classified by thermal stability and decomposition behaviour.
• Class 6.1 — Toxic substances: pesticides, methanol, and industrial chemicals that are toxic through ingestion, inhalation, or skin absorption.
• Class 6.2 — Infectious substances: clinical waste, biological cultures, and medical diagnostic specimens from healthcare facilities.
• Class 7 — Radioactive material: medical isotopes, industrial gauging sources, and nuclear fuel — subject to IAEA requirements that layer above the standard ADR framework.
• Class 8 — Corrosives: sulphuric acid, caustic soda, hydrochloric acid, battery electrolyte, and electroplating solutions.
• Class 9 — Miscellaneous dangerous substances: lithium-ion and lithium metal batteries, dry ice, magnetised material, and environmentally hazardous substances. Lithium batteries are the most frequently misclassified cargo in European road freight. Batteries in consumer electronics, power tools, electric vehicles, and industrial storage systems all fall under Class 9 — UN 3480 applies to lithium-ion cells and batteries transported alone; UN 3481 applies to batteries packed with or contained in equipment. Whether full ADR requirements or limited quantity exemptions apply depends on the watt-hour rating and packaging configuration confirmed for that specific battery in ADR Table A. The dangerous goods in European road freight cluster covers substance classification, exemption thresholds, and labelling requirements across all 9 classes.

What Are ADR Packing Groups?

Packing Group I, Packing Group II, and Packing Group III rank the hazard severity of substances within most ADR classes — I is the highest danger, III is the lowest.

• Packing Group I applies to the most hazardous substances within a class. For Class 3 flammable liquids, Packing Group I means substances with a boiling point at or below 35°C, or a flash point below 23°C combined with a high vapour pressure. Packaging standards, quantity limits, and labelling requirements are strictest at this level.
• Packing Group II covers industrial chemicals, solvents, and chemical intermediates that form the bulk of routine chemical road freight across European supply chains. Most packaged chemical consignments moving between manufacturing sites and distribution facilities fall at this level.
• Packing Group III applies to lower-hazard goods — diesel fuel, certain paints, and some cleaning products. Goods at this level are most likely to qualify for limited quantity (LQ) exemptions at commercially standard package sizes, reducing compliance obligations for smaller consignments.

Classes 1, 2, 5.2, 6.2, and 7 do not use packing groups — these classes carry their own internal sub-classification systems. For all other classes, the packing group is confirmed in ADR Table A alongside the UN number and transport conditions for that substance.

What Documents Are Required for ADR Transport?

Four documents travel with every ADR road freight consignment: the transport document, the Safety Data Sheet, the Written Instructions, and the ADR driver certificate.

• The transport document states the UN number, the proper shipping name as listed in ADR Table A, the hazard class, the packing group where applicable, the total quantity and packaging type, and the full names and addresses of the consignor and consignee. A compliance declaration signed by the consignor confirms the load has been prepared in accordance with ADR. This document stays with the shipment from collection to final delivery and is produced for enforcement inspection at any point in transit.
• The Safety Data Sheet is the 16-section technical document covering the substance's physical and chemical properties, hazard classification, exposure limits, and emergency response procedures. It is required under REACH Regulation (EC) 1907/2006 and CLP Regulation (EC) 1272/2008 for all classified substances and accompanies the transport document throughout the journey.
• The Written Instructions — the Tremcard — are the emergency response card kept in the cab throughout transit. They specify the driver's actions in the event of accident or incident involving each substance on board and must be written in the languages of the country of origin, every transit country, and the destination country. A load of French chemicals entering Germany and continuing into Poland requires the card in French, German, and Polish.
• The ADR driver certificate is issued after completion of a certified ADR training programme. The basic certificate covers general dangerous goods transport and is valid for 5 years, renewed by a refresher course and examination taken before expiry. Separate class-specific extension certificates are required for tank transport, Class 1 explosives, and Class 7 radioactive materials. A standard HGV or CE driving licence does not cover ADR goods — the certificate is an entirely separate qualification.

What ADR Exemptions Apply in European Road Freight?

Two exemption categories reduce or eliminate ADR requirements for small quantities of specific dangerous goods: limited quantities and excepted quantities.

• Limited quantities (LQ) allow qualifying dangerous goods in small consumer-type packaging to travel under simplified compliance — no orange plates on the vehicle, no ADR driver certificate required, and a simplified transport document. Thresholds are substance-specific and set per UN number in ADR Table A. For Class 3 flammable liquids at Packing Group II, ADR Table A sets the inner packaging limit at 1 litre and the gross outer packaging limit at 12 litres. LQ-qualified packages carry a diamond-shaped LQ mark in place of full hazard labels and placards.
• Excepted quantities (EQ) apply to quantities even smaller than LQ thresholds — set per UN number in ADR Table A at milligram or millilitre levels per inner packaging — and exempt the consignment from almost all ADR requirements except basic packaging integrity and compatibility.

Both exemptions are consistently misread. Exemption eligibility is determined by the specific UN number, the packing group, and the packaging configuration — not by the volume or weight of the consignment alone. A substance with no LQ or EQ allowance assigned in ADR Table A is subject to full ADR compliance regardless of how small the package is.