A method for the determination of source parameters for estimation of road vehicle noise has been developed. The main parts of the method have been tested with measurements and this verifies that the method can be used in practice. The method, as finally formulated, has not been tested, and this should be done in a Round-Robin test. Despite this, it is recommended to forward the method suggestion to the International Organisation for Standardisation (ISO). This is due to the lack of a corresponding method and the current need for the method within the EU. The method is needed in view of the development of new noise mapping methods (HARMONOISE) with background in the recent EU noise directive.
The method estimates the expected value of the sound power of a population of vehicles. Furthermore the method estimates the weight of the sub-sources in thevehicle model and the ground impedance of the road surface. The method is based on statistical modelling and gives in particular estimates of the expanded uncertainty (ISO GUM) for all of the above mentioned parameters. The report gives, together with two previous reports [SINTEF Report STF40 A02050, SINTEF Report STF40 A03063], the background for the suggested method.