Gis for the Evaluation of Road Traffic Noise at Areas Facing Roads in Japan –key Functions including Estimation of the Numbers of Residents in Buildings–

GIS is an effective tool to accumulate various kinds of numerical maps and the attribute data relating to road traffic noise and to analyze the correlations between the data. In addition, combining prediction method of the road traffic noise with the benefits of GIS allows us to evaluate the noise field, from the past to the future, at areas facing roads concerned. Since propagation of road traffic noise is remarkably affected by buildings or other obstacles along the roads, their physical properties such as the locations and the heights should be carefully taken into account to calculate the road traffic noise. For evaluation of noise exposure by road traffic, it is important to distinguish between residential and non-residential buildings along the roads and then estimate the number of residents in each building. However, reasonable method to assign the population to the residential buildings, especially to the condominiums, is still a problem to be solved, because of limitations of information involved in the relating databases. The authors have shown a basic idea for calculating the number of people in the residential buildings and have been developing the method, in which the building maps and the population by the national census are used on GIS. In this paper, we discuss some key functions on the GIS application, including assignment of the residents, which are essential to be widely used for management and assessment of the road traffic noise.