This part of ISO 21069 describes a procedure that generates comparable measurement results in roller brake testing, such that the efficiency of the service braking system can be assessed reliably wherever the roller brake tests are performed. The following items are covered in this part of ISO 21069: ⎯ symbols and definitions; ⎯ test methods; ⎯ test conditions; ⎯ test equipment required; ⎯ accuracy of test equipment; ⎯ data recording and calculation needed; ⎯ presentation of results; ⎯ assessment criteria for pass/fail. The procedure described in this part of ISO 21069 is not applicable to passenger cars.