Abstract
When the road administrations have used all technically feasible and economically possible measures to reduce the noise, there can still be a need for further reduction of the annoyance. Analyses reveal that only about 1/3 of the variance in the annoyance response is caused by the noise level itself, the other 2/3 are determined by so-called non-acoustic factors. The annoyance response therefore can be altered without changes to the actual noise level. The FAMOS project quantify how different factors modify people's subjective reactions to traffic noise. A literature survey has been carried out and experimental tests using sound walks, questionnaires and listening tests have been performed. The result was a European guidebook with practical applications for the National Road Administrations on how to handle noise annoyance by non-acoustic moderators in planning of roads etc.