Tunnel restriction code
In 2007 a tunnel restriction code was introduced with the European Convention on the International Transport of Hazardous Goods by Road (ADR = Accord européen relatif au transport international des marchandises Dangereuses par Route). The tunnel restriction code defines which tunnels can be driven through by which hazardous goods transports. All tunnels in the European Union are allocated to a tunnel restriction category. There are five categories in total.
Generally speaking, it can be said: the higher the tunnel category, the higher the restrictions.
A No restriction for hazardous goods.
B Prohibited for the transport of hazardous substances which could cause a very large explosion.
C The same restriction as for B, plus hazardous goods which could cause a large explosion or the extensive release of toxic substances.
D The same restrictions as for C plus hazardous goods which could cause a large fire.
E Prohibited for the transport of all hazardous substances. There are some exceptions for certain radioactive substances, clinical waste and samples.