Traffic Noise Model

Readme file for FHWA TNM V1.0b:

A new executable, TNM Version 1.0b, is now available. This new version includes the following:

• Addresses fatal floating-point error crashes - Through extensive testing of the new version, Version 1.0b eliminates all known fatal crashes, with two exceptions (a "SQRT Domain" and a "HPP Count Mismatch" error). Due to schedule constraints, these two exceptions will be addressed in Version 1.1.
• Implements an error-catching mechanism - For any other possible fatal errors, these errors will be detected during computations, but will no longer be fatal crashes. Computations will continue and those receivers for which the error occurred will be flagged as "invalid" in the Results, Sound Levels table. Note: Please send any runs which encounter errors to the Volpe Center as soon as possible.
• Implements two small changes in the acoustics -
  1. In fixing the fatal crashes, a mis-assignment in one of TNM's computation variables was discovered. This resulted in an average 0.1-0.2 dB difference at receivers for some geometries. Appendix E in the User's Guide displays the sound level results computed using TNM Version 1.0 for the official TNM test case. The sound level results computed using TNM Version 1.0b are attached at the bottom of this file; and
  2. In the computation of the community noise equivalent level (Lden), a 5-dB penalty is added to evening operations, which equates to a 3.16 weighting factor (TNM Version 1.0). For consistency with California state law, who is the primary user of the Lden metric, a weighting factor of 3.00 has been implemented in TNM Version 1.0b.
• Addresses data base (DB) errors - A new function, Cleanup Run, has been implemented under the File menu. For runs with DB error messages, this function removes these errors from the corrupted files. When the Cleanup Run function is selected, a dialog asking the user to backup and close the run is displayed. When the user selects OK, a dialog (similar to when opening a run) is displayed; then the user can select the desired run to "clean."
• Implements two new input error checks - In input check, (1) detect single point objects and two-point zones, e.g., a roadway consisting of zero or one point and a tree zone consisting of zero to two points will produce an input error; and (2) detect objects overlapping a roadway, with exception of other roadways.

There are currently three files for Version 1.0b on the TNM web-page:

1. This Readme file
2. a downloadable TNM Version 1.0b executable (TNM1_0B.EXE) and
3. a downloadable NMPlot Version 3.06 executable (NMPLOTX.EXE).

To use Version 1.0b, download the file TNM1_0B.EXE, rename it to TNM.EXE, then replace the existing TNM.EXE file located in your TNM/PROGRAM directory with the new executable file.

The previous version of NMPlot was having difficulties running on very fast computers (typically faster than 200 MHz) giving some users a runtime error message. The developer of NMPlot has recently released a new DOS version of NMPLOT, Version 3.06, which corrects this error. To use Version 3.06, replace the existing NMPLOTX.EXE file located in your TNM/PROGRAM/NMPLOT directory with the new executable file.