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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 will complete development of the acoustic functionality of TNM 3.0 and provide that to FHWA. The FHWA plans to pursue a variety of alternative approaches to complete TNM 3.0 development. If you have any questions please contact Mark Ferroni at or Adam Alexander at

UPDATE: The FHWA has issued a broad agency announcement for TNM 3.0 development. Please contact the POC in the BAA for more information about submission of proposals.

Below are enhancements that have been implemented into the FHWA Traffic Noise Model, version 3.0. There are currently numerous other enhancements that are being implemented or planned to be implemented. The below list will be updated as items are completed.

  1. When an input dialog box is in the background, make it active if a user clicks on a tab or the tab background.
  2. Change the File dialog boxes (Open, Save, and Save As) to be consistent in look and functionality with MS-Windows standard File dialog boxes.
  3. Clarify information displayed in input dialog boxes.
    • Indicate which parameters in the input dialog headers are for default data and which are for a specific object.
    • Fix the text for Lden the header of the Roadway Input dialog box so that it says "Evening: 7pm-10pm" instead of "Evening: 7pm -".
    • In the Roadway Input dialog box, change the text in the tab, LAeq1h Hourly to LAeq1h Volumes.
  4. Increase the spreadsheet functionality of dialog boxes and tables.
    • Allow pasting of one cell into multiple cells where applicable.
    • Add the ability to copy/paste between runs.
  5. Change the label for the large minus sign in the input dialog boxes from DELETE to DELETE ENTIRE OBJECT.
  6. Add context menus that provide useful functions/actions for objects. The menus should be accessible by right clicking on the object.
    • Add context menus where appropriate. Edit functions would be useful. For example, in the Plan View, right-clicking on a roadway could bring up a list of menu choices to delete the object, reverse direction, or open the Roadway Input dialog box.
  7. Add buttons in the input dialog boxes to insert/append a single blank row in a manner similar to the menu options INSERT ROW and APPEND ROW.
  8. Automatically backup original TNM run files before overwriting with new data.
    • After any input change, TNM requires the run to be saved to the old name before allowing the run to be saved to a new name.
  9. Purge deleted TNM objects from the run's .dat and .idx files when the run is re-saved.
    • When TNM objects are deleted from a run and the file is resaved, the file size of the .dat and .idx files do not decrease. Remove the deleted TNM objects from the .dat and .idx files when saving.
  10. Always increment sequence numbers for input objects successively.
    • Sometimes TNM skips sequence numbers for its input objects.
  11. Remove the ghosted scroll bar that remains on the Roadways input dialog box if the window is resized when the Traffic (Lden, LAeq1h, etc.) tab is active.
    • Maximizing the Roadways input dialog box when the Traffic tab is the active tab creates a ghost of the previous window and partially covers the display of the newly maximized window.
Updated: 2/14/2013
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