UNR WLTP having features that have not been seen before in Regulations of the 1958 Agreement and GRPE therefore decided to commission this document to assist all users of this Regulation in their understanding. UNR WLTP will have 3 Levels. There are two regional Levels (contained within Level 1), and one harmonised Level (Level 2). The regional Levels reflect the current (at the time of adoption) emissions legislation in the EU (Level 1A) and in Japan (Level 1B). The harmonised level is the only level which will be accepted as part of an approval to Regulation 0 (International Whole Vehicle Type Approval – IWVTA)