Measurements have been carried out in the laboratory and in the field to collect data to use to validate the Harmonoise source model for heavy vehicles. In general the results support the Harmonoise source model in all other aspects than the coefficients in the equations yielding the sound power level of propulsion and tyre/road noise. Nordic measurement results indicate that many of these coefficients need to be revised. New coefficients are proposed. Different methods to separate propulsion and tyre/road noise are discussed and some measurements combined with a transfer matrix method indicate that the point source model of Harmonoise functions reasonably well. Field measurements, which focused on simulation of urban driving, clearly show that acceleration has to be taken into account for heavy vehicles. The sound exposure level increases significantly during acceleration at low speeds and it is not possible to make accurate calculations for heavy vehicles in urban traffic without correcting for it. One way of doing this could be quite simply to add a default acceleration of approximately 0,5 m/s2 for heavy vehicles in urban traffic. For driving on roads with gradients the Volvo laboratory measurements support the simple Harmonoise model quite well at least if the gradient is small. The results will be further developed and discussed in the European IMAGINE-project.