Because the carriage of dangerous goods can cross national boundaries, the UK regulations refer extensively to international agreements. The ADR international agreement (European Agreement concerning the International Carriage of Dangerous Goods by Road or Accord European relatif au transport international des marchandises dangereuses par route) is for road transportation and the RID international agreement concerning the carriage of dangerous goods by rail or Reglement concernant le transport international ferroviare des marchandises dangereuses) is for rail transportation.