ADR glossary
Not the full list of definitions in chapter 1.2. These are the fourteen terms that actually come up on a booking call, defined plainly, with the Dutch equivalent beside each one.
| Term | What it means |
|---|---|
| ADR | The European agreement on the international carriage of dangerous goods by road. It is what every other term on this page hangs off. |
| UN number | A four digit number that identifies a dangerous substance. It is the identifier, not the name, and it is the same in every language and every document. |
| Packing group | The degree of danger within a class: I high, II medium, III low. It drives packaging and, with the class, much of the equipment. |
| Class label | The diamond that shows the hazard class on the package or the vehicle. A subsidiary hazard gets its own diamond. |
| Hazard identification number | The number on the upper half of the orange plate, historically called the Kemler number. 80 is a corrosive substance. |
| Class 8 | Corrosive substances, acids and alkalis. They often need a lined tank because they attack steel. |
| Lined tank | A tank vehicle with a rubber or plastic lining that withstands corrosives which would destroy bare steel. |
| CMR | The international consignment note and the liability convention behind it for road freight. |
| The 1000 point rule | An ADR exemption for smaller quantities, worked out as quantity multiplied by the factor for the transport category. |
| GDP | Good Distribution Practice, the standard for carrying medicines, with a validated cold chain and documented handover. |
| SQAS | Safety and Quality Assessment for Sustainability, the assessment scheme the European chemical industry uses on its carriers. |
| Backhaul | A load that fills a leg a vehicle was going to run empty anyway. It is the main reason a rate can be lower on one direction than the other. |
| Transport category | A rating from 0 to 4 in column 15 of table A. It sets the factor used in the 1000 point rule and cannot be derived from the class. |
| Tunnel restriction code | A letter from A to E in column 15 that says which tunnel categories a load may pass. It is what actually closes a route. |
The three that cause the most confusion
UN number and hazard identification number get mixed up constantly. They sit on the same orange plate, one above the other. The lower number identifies the substance and never changes; the upper number describes how it behaves and can be shared by substances that have nothing else in common.
Transport category and class are the second pair. The class is the hazard, the transport category is a rating from 0 to 4 that sets the multiplier for the 1000 point rule, and you cannot derive one from the other. The third is packing group, which is a degree of danger inside a class and not a type of packaging, whatever the name suggests.
Why the Dutch column is here
Because a load moving through the Netherlands meets Dutch paperwork and a Dutch inspector, and the terms do not always map word for word. Gevaarsidentificatienummer and hazard identification number are the same thing; Kemlergetal is the older name for it and still gets used on the phone.
Frequently asked
Is the Kemler number the same as the hazard identification number?
Yes. Kemler number is the older name. It is the number on the upper half of the orange plate.
Is packing group about the packaging?
No, despite the name. It is the degree of danger within a class: I high, II medium, III low.
Can I work out the transport category from the class?
No. It is given per UN number in column 15 of table A.
Related references
Take the data
Source
The terms are drawn from ADR chapter 1.2 and from the working vocabulary of specialist transport, as recorded in our German reference set. The English and Dutch definitions are ours, written to be usable on a booking call rather than to reproduce the regulation. This is a selection of fourteen terms, not the full set of definitions in chapter 1.2, and the official ADR text governs.
Cite this page
Vektor Group. ADR glossary. 2026. https://vektorgroup.eu/adr-glossary
Rather just ask someone?
Send the UN number and the route. We return the class, the packing group, the hazard identification number and the tunnel code, in plain terms.
Start an enquiry →