This International Standard specifies the essential characteristics of a test surface intended to be used for measuring vehicle and tyre or road noise emissions. The surface design given in this International Standard — produces consistent levels of tyre or road sound emission under a wide range of operating conditions including those appropriate to vehicle sound testing, — minimizes inter-site variation, — provides minor absorption of the vehicle sound sources, and — is consistent with road-building practice. NOTE For the purposes of this International Standard, the terms noise and sound are used interchangeably.