The Restriction Code Table
These are the twelve tunnel restriction codes that appear in the served ADR 2025 dataset, with the number of UN entries carrying each. The two quantity-qualified codes, (B1000C) and (C5000D), appear only on Class 1 entries — the threshold is the net explosive mass per transport unit.
| Code | Carriage in tanks | Other carriage (packages) | What it means for routing | UN entries |
|---|---|---|---|---|
| (B) | Prohibited in B, C, D, E | Prohibited in B, C, D, E | Category A tunnels only. | 72 |
| (B1000C) | — | Net explosive mass over 1,000 kg per transport unit: prohibited in B, C, D, E. At or under 1,000 kg: prohibited in C, D, E | Class 1 quantity-qualified: A only above 1,000 kg NEM; A and B at or under it. | 196 |
| (B/D) | Prohibited in B, C, D, E | Prohibited in D, E | Tanks: A only. Packages: A, B, C. | 82 |
| (B/E) | Prohibited in B, C, D, E | Prohibited in E | Tanks: A only. Packages: A, B, C, D. | 56 |
| (C) | Prohibited in C, D, E | Prohibited in C, D, E | Categories A and B. | 7 |
| (C5000D) | — | Net explosive mass over 5,000 kg per transport unit: prohibited in C, D, E. At or under 5,000 kg: prohibited in D, E | Class 1 quantity-qualified: A, B above 5,000 kg NEM; A, B, C at or under it. | 52 |
| (C/D) | Prohibited in C, D, E | Prohibited in D, E | Tanks: A, B. Packages: A, B, C. | 120 |
| (C/E) | Prohibited in C, D, E | Prohibited in E | Tanks: A, B. Packages: A, B, C, D. | 219 |
| (D) | Prohibited in D, E | Prohibited in D, E | Categories A, B, C. | 105 |
| (D/E) | Prohibited in D, E (bulk or tanks) | Prohibited in E | Bulk/tanks: A, B, C. Packages: A, B, C, D. | 903 |
| (E) | Prohibited in E | Prohibited in E | Every category except E. | 1,076 |
| (-) | No restriction | No restriction | All tunnel categories. | 21 |
Entry counts derive from the served dataset at build time. Look up any UN number in the ADR lookup to see its code in context — every UN entry page shows the tunnel restriction code alongside class, packing group and transport category.
Glossary: this code is called the tunnelcode or tunnelbeperkingscode in Dutch and the Tunnelbeschränkungscode in German — the same ADR column 15 value in every language.
The Five Tunnel Categories
Tunnels are classified into five categories based on the level of restriction they impose. Category A is the least restrictive and Category E is the most restrictive:
Category A — No Restrictions
No restrictions on the transport of dangerous goods beyond the general ADR provisions. Most motorway tunnels and short tunnels fall into this category.
Category B — Restricted
Restricts dangerous goods that could lead to a very large explosion. Affected: Class 1 goods in large quantities, certain explosives precursors, and some self-reactive substances.
Category C — More Restricted
Restricts goods that could lead to a very large explosion, a large explosion, or a large toxic release. Includes all Category B restrictions plus certain toxic gases, flammable liquids in tanks, and toxic liquids.
Category D — Highly Restricted
Restricts goods that could lead to a very large explosion, a large explosion, a large toxic release, or a large fire. In addition to Category C restrictions, this includes most flammable liquids and flammable gases in significant quantities.
Category E — Most Restricted
Restricts all dangerous goods other than those carried under exemptions (e.g., 1.1.3.6 small quantities, limited quantities, or excepted quantities). Essentially, only fully exempt loads may pass through Category E tunnels.
UK-Specific Tunnel Restrictions
The UK has several major tunnels with dangerous goods restrictions. While the UK follows ADR tunnel categorisation, some tunnels have additional or specific rules:
- Dartford Crossing (Dartford Tunnel): Category E tunnel. Most dangerous goods loads must use the Queen Elizabeth II Bridge (eastbound). Westbound traffic through the tunnel has significant DG restrictions. Vehicles carrying dangerous goods must display appropriate orange plates and contact the tunnel operator.
- Channel Tunnel (Eurotunnel): Has its own comprehensive dangerous goods rules that go beyond standard ADR tunnel codes. A specific list of prohibited and restricted goods applies. Consignors must declare DG loads in advance, and certain classes (notably Class 1 and Class 7) are completely prohibited. Always check the current Eurotunnel dangerous goods policy before booking.
- Tyne Tunnel: Restrictions on dangerous goods transport, particularly for flammable liquids and gases. Category D applies to the older tunnel bore; check current restrictions for the new tunnel bore.
Practical Tips for Route Planning
- Always check tunnel codes before planning a route, not after loading
- If a tunnel restricts your load, plan an alternative surface route in advance
- Night-time or weekend restrictions may apply — some tunnels only restrict DG during peak hours
- Mixed loads take the most restrictive tunnel code of all goods on board
- Loads carried under the 1.1.3.6 small-load exemption, limited quantities or excepted quantities can generally pass through all tunnel categories, but check local rules
- Keep tunnel restriction codes visible in your transport documentation
ADR reference information only. Classification and compliance are the consignor's and carrier's legal responsibility. Always verify against the current ADR in force and consult a qualified DGSA where required.