What is an ADR tunnel code?
In Europe, road tunnels are categorised A to E by risk (A least restricted, E most restricted).
The tunnel restriction code on a dangerous goods load tells you which tunnel categories the vehicle may not pass through; ✗ means forbidden for that category.
Prohibitions can differ for tank carriage versus packaged (carton/drum) carriage. HazSeal surfaces the sealed Table A code and explains the letters — it does not replace reading ADR 8.6.4 for your load.
ADR 8.6.3 / 8.6.4
Plain-language orientation with article references. Not a certification. Where HazSeal cannot decide from sealed data, it answers NEEDS_REVIEW.