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SoundPLAN - Road Noise Calculation Module

In 1995 the SoundPLAN developer incorporated the propagation model described in Federal Highway Administration (FHWA) RD-77-108.  In addition the implementation also included the correction for the vehicle mix such as the California Vehicle Noise Emission Levels (Calvino).

In 2001 the SoundPLAN developer started on the incorporation of the FHWA Traffic Noise Model (TNM ™) into the SoundPLAN programming code. In 2006 SoundPLAN finalized the implementation of the TNM v2.5 noise emission and noise prediction methodology.   The SoundPLAN developer is in contact  with FHWA and Volpe to resolve the difference that still remain in the noise prediction calculation.

 

Note: The Federal Highway Administration Traffic Noise Model (FHWA TNM™) is protected by U.S. copyright laws. The noise prediction methodology used in SoundPLAN has been designed to be consistent with the FHWA TNM (TM), however, SoundPLAN has not been tested, evaluated, or approved for use by any Agency of the U.S. Government.

 

TNM Data Export / Import Interface

The SoundPLAN software offers a TNM v2.5 interface.  TNM v2.5 project data (i.e., road, elevation line, barriers, receptors, ground definitions areas) are directly imported with the geometry and attributes into a SoundPLAN project.  SoundPLAN projects geometry and attributes are exported back into a TNM v2.5 project files (*.dat, *.idx).

 

Road Noise Model Contour Maps

The following graphics show the results computed with the SoundPLAN implementation of the FHWA TNM v2.5 prediction methodology. 

  1. Top Left: Noise Contour Map Site Plan with 3 blue line indicated the location of the three lines for the Cross Noise Map

  2. Top Right: 3D Isometric View with Noise Contour Map a 5 ft above the ground

  3. Three Cross Section Maps below - Note the results clearly demonstrate the deficiency in the current FHWA TNM 2.5 model.  The FHWA TNM 2.5 model currently only use 2-D distance calculation (x, y) instead of a 3D distance calculation (x, y, h)

The following graphics show spectral results computed with the SoundPLAN implementation of the FHWA TNM 2.5 version.  The graphic indicate that the 250 Hz to 2 kHz octave bands are significant contributors to the overall noise impact.

  1. Top Left - City Noise Map Receiver Mesh

  2. Top Right - Ground Topography Map

  3. Eight Octave Band Noise Contour Maps from 63 Hz to 8 kHz

  4. Overall Level Noise Contour Map

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Last modified: March 29, 2010