Geographical information system for traffic noise analysis and forecasting with the appearance of barriers

This paper describes a road traffic noise calculation and visualization package TNoiseGIS. It is implemented by utilizing the inbuilt database and spatial routines of a popular commercial Geographical Information System (GIS). The noise calculations can be made according to either of two alternative noise calculation models: the UK CORTN and US FHWA models. These models are applicable for calculating noise levels along highways with free flowing traffic. By applying the inbuilt spatial operations to the geographically located information, noise emission values can automatically be provided for any number of receptor points using either algorithm. The graphical user interface of the GIS simplifies the input of the attributes of the different receptor points and road links. Line and block barriers can be defined and applied with the interpolation technique for calculating traffic noise on receiver points along the back edge of barrier parallel to roadway. As a result, all noise levels behind the barrier can be efficiently estimated. In addition to the calculation of noise emission values for a specified set of receptor points, the variation in the noise levels along the highway can be visualized in the form of noise contours. Such contours provide a visual description of the soundscape and also information on the importance of different factors for soundscape quality. By changing traffic flow parameters such as the localization of planned roads, dwellings, and barriers with different size and location, TNoiseGIS functions as a road traffic noise prediction tool and a tool for planning environmentally friendly road and road traffic noise solutions. The noise calculations and visualization algorithms are implemented by means of scripts that will be made available at a lower cost and also user modifiable.