Pixels, chisels and contours - technical variations in European road traffic noise exposure maps

Area of Science:

• Environmental Science
• Geographic Information Systems (GIS)
• Public Health

Background:

• Motorized traffic generates significant road noise, impacting human health, quality of life, and social behavior.
• The European Noise Directive (END) mandates strategic noise mapping for urban areas and major roads to inform noise action planning and environmental exposure analyses.
• Existing END noise maps exhibit limitations including vague definitions, data inconsistencies, geometric artifacts, and topological errors, hindering comparability and usability.

Purpose of the Study:

• To provide practical insights for end-users of noise mapping data and advocate for clearer regulations within the European Noise Directive.
• To highlight how variations in noise map data processing limit comparability in environmental impact assessments.
• To assess the spatial properties of reported noise data and produce a nation-wide dataset for environmental health analyses.

Main Methods:

• Compilation and analysis of 84 German noise assessments reported under the END.
• Graphical and spatial metric analysis to review the shape, structure, and geometric alterations of noise contour maps.
• Examination of different raster-to-polygon conversion implementations for geodata management.

Main Results:

• Identified significant data inconsistencies and geometric artifacts in END-compliant noise maps, affecting population exposure statistics.
• Demonstrated how variations in data processing and geometric alterations impact the accuracy of exposed population share calculations.
• Produced a nation-wide dataset of yearly averaged noise level indicator (Lden) for 2017, serving as a foundation for environmental health studies.

Conclusions:

• The current implementation of the European Noise Directive presents challenges for data consistency and comparability, necessitating refined regulations and standardized post-processing methods.
• Accurate and comparable noise mapping data is crucial for effective environmental health analyses and urban planning.
• The study's findings and the generated dataset offer valuable resources for researchers and policymakers addressing noise pollution and its health impacts.