Most countries have a national noise policy to protect citizens from undesirable environmental noise levels from road, rail and air traffic and industrial sources. The European Noise Directive for the Assessment and Management of Environmental Noise outlines a coordinated method to achieve noise reduction in large cities as a first step, followed by smaller cities as a second step. The directive requires Member States to create strategic noise maps of all areas with a population over 250,000, roads with more than 6,000,000 vehicle passages per year, major railways with more than 60,000 train passages per year and major airports within their territories by 30 June 2007. By 2008, Member States shall ensure that authorities have developed action plans to identify noise exposure, adequate noise reduction measures and long term noise reduction strategies.
To accomplish these goals, city planners will be using noise planning software to map entire cities. The objectives are to determine the current and future noise exposure, to identify noise issues and to develop scenarios to reduce noise. SoundPLAN is the leading noise planning and mapping software used worldwide for these purposes.
SoundPLAN is noise simulation software designed to model noise from road, railways, aircraft, leisure and industrial sources. The software has implemented all major international noise propagation standards. Engineers worldwide use SoundPLAN to develop 3D noise models for all types and sizes of noise projects.
Today many city planning departments have GIS based maps. The GIS database can greatly reduce the generation time of 3D noise models. The basic geometry and noise significant parameters are imported into SoundPLAN. For defining roadways, for example, the significant parameters are traffic volume, vehicle mix, vehicle speeds and road surface. SoundPLAN manages different road scenarios by creating Geo-Files which are assembled into Situation/Planning scenarios. The Situations are used to create noise maps. A noise contour map of Santiago de Compostela, Spain, is shown below.
Situations can be arranged at will to simulate before and after scenarios for different traffic forecasts. All noise contour maps can be depicted as 2D or 3D. An animation feature allows the user to drive through an area to visualize the project geometry, results or the design of a noise barrier. SoundPLAN graphics output allows even laymen to understand the pro’s and cons presented.
In addition to contouring the results for a specific noise prediction calculation, SoundPLAN also allows the presentation of difference maps and conflict maps. Difference maps present the dB difference between two scenarios. Conflict maps show the difference between the predicted noise level and the noise limits.
SoundPLAN uses Façade Noise Maps to automatically predict noise exposure. The prediction results document the noise level and the number of people for each floor of a building during the day or night. The results can be a key factor in deciding how to spend tax dollars on noise mitigation planning. The following map shows noise zones for rooms during the day and night for a specific building.
An optimization tool such as SoundPLAN’s Wall Design is very important for engineers involved in noise control along roads or railroad lines. Wall Design pre-calculates the future noise barrier along the road or railroad. During the pre-calculation, a database is generated that allows the user to design the most cost effective wall to meet the noise level target. In addition to the economic criteria, Wall Design allows the user to manually overwrite the proposed noise barrier and to consider aesthetic requirements. The Wall Design optimizing histogram allows the user to determine the most effective barrier setup by showing the breakpoint of cost vs. noise reduction. The following graphic is a Cross Sectional Noise Contour Map showing the positive effects of the noise barrier for reducing road noise in the immediate area of the wall.
The goals of the END to initiate noise mapping using methods of assessment common to the Member States, to create action plans to reduce noise where needed, and to make information about environmental noise and its effects on humans available to all is a monumental task. The use of noise mapping as an initial method of noise assessment and the requirement of action plans to reduce the noise impact will eventually help to lower the noise impact in EU communities. As citizens begin to reap the benefits of such actions, let us hope that these high aims to protect people from excessive noise move beyond the European Union.