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Traffic Noise Model

FHWA Traffic Noise Model Version 3.0

In 2008, the TNM 3.0 development team, consisting of FHWA and Volpe Center staff, selected the Manifold 8.0 Professional Runtime library to incorporate GIS functionality and 2D graphics in the FHWA TNM 3.0. In late 2011 the FHWA Office of Chief Counsel, expressed concerns about requiring use of TNM 3.0 due to the presence of Manifold since users would have to purchase a license from a single proprietary source to use software required by regulation. The Office of Chief Counsel advised that FHWA would not be able to require use of TNM 3.0 until such a time as other software was deemed consistent with the methodology of TNM per 23 CFR 772.9(a). The FHWA decided to continue development as planned and work with interested software developers to satisfy 772.9(a) and pursue development of an alternate version(s) of TNM that would not include use of software with a fee based license to incorporate 2D graphics and GIS functionality following completion of TNM 3.0.

During the summer of 2012, the development team discovered that basic functionality that appeared to be present in the Manifold 8.0 Professional Runtime library was not included. In discussions with Manifold, they informed the development team about a next generation product to replace the current Manifold 8.0 Professional Runtime. These issues led to reconsideration of the approach to completing TNM. At this point, FHWA decided that the best course of action would be to complete the acoustic and persistence libraries for TNM 3.0 and seek alternative approaches to incorporate these libraries inside other CAD or GIS frameworks. To achieve this, the development team completed development of the acoustic functionality of TNM 3.0 and provided that to FHWA.

The FHWA issued a BAA to complete TNM 3.0 development. In late 2015 the TNM 3.0 software underwent Beta Testing by selected State DOTs. Currently the development is addressing those comments in addition to optimizing the model to reduce run times. If you have any questions please contact Aileen Varela-Margolles at

Updated: 6/30/2016
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