This work makes a contribution to the study of the influence of different elements andcharacteristics of urban environments in the application of the ISO 1996 standard inorder to obtain strategic noise maps, following the guidelines of European NoiseDirective 2002/49/EC.Accuracy in the knowledge of the sound field incident on a façade is essential for properplanning of control actions. Independent of the chosen method for noise mapping, if wewish to know the exposed population, it is essential to measure the incident noise levelon the façade. In connection to this topic, the ISO 1996 standard is considered in theEuropean Noise Directive as a reference in the elaboration of strategic noise maps.Moreover, noise maps are regarded in the Directive itself as the main tool for assessingthe exposure of the population to noise pollution. Regarding the geometry of themeasuring point in relation to the façade and other elements of the environment, thenormative part of the ISO 1996-2 standard only makes reference to the distance betweenthe microphone and the façade. The remainder of the geometric aspects that couldinfluence the result of a measurement are either not taken into account in the standard orare considered in Annex B, which is only informative.In order to approach the problem, this work presents a detailed review of the literatureand proposes research strategies in order to study the relationships between the ISO1996-2 standard’s measurements procedure and the accuracy of the estimations of noisedoses received by people obtained by the application of the European Noise Directive.The results show significant relative differences with respect to the values proposed bythe standard for the corrections, and indicate the possibility of the influence of theseresults on the accurate development of strategic noise maps.Then, an experimental study is proposed through “in situ” measurements of thecorrections proposed by the ISO 1996-2 standard according to the position of themicrophone. Based on the analysis carried out, it can be concluded that, in order tocompare the results of sound measurements in various urban environments and atdifferent distances from the façade, it is appropriate to make corrections not only forfaçade reflection, but also for distance to the source. In connection to this issue, theimportance of the presence of obstacles in the measurement environment is suggested.This can affect the propagation of the sound field and, therefore, both the application ofthe corrections proposed by the ISO 1996-2 standard and the noise maps developed bythe calculations.The ISO 1996-2 standard itself indicates that reflective obstacles present in urbanenvironments may influence the propagation of sound to the receiver under study. Inthis regard, when noise maps are made through computational methods, the presence oflines of parked vehicles on the sides of urban streets is not usually considered; butrecent studies suggest the possibility that its effect on real exposure to noise on buildingfaçades is not negligible. In this study, the effect of parking lines in urban street designon sound level distribution is studied with the Boundary Element Method (BEM). Ascreening effect associated with the presence of parking lines is observed. This effectvaries depending on the height of measurement and the distances between the soundsource, the parked vehicles and the façade of the buildings. The results show that theeffect can be significant in many urban street configurations in order to determine theexposure to traffic noise of dwellings. As a consequence, if it is not considered, theaccuracy of the outcomes of the noise maps conducted according to the European NoiseDirective can be influenced.
