2.Prior to the tests, the technical service shall ensure that the selected surface meets the specified requirements and shall be informed of the test method to determine R, the type of vehicle (tractor, etc.) and the axle load and tyres (different loads and different tyres have to be tested and the results shown to the technical service which will decide if they are representative for the vehicle to be approved).
2.1.The value of R shall be mentioned in the test report.
The calibration of the surface has to be carried out at least once a year with a representative vehicle to verify the stability of R.