Based on verification described in the FHWA Traffic Noise Model Technical Manual, the FHWA determined the model was valid and fully acceptable for use.
Additional validation is necessary to provide increased confidence in the model's results.
Field measurements made to support the model validation will be used to begin study of atmospheric effects on the propagation of highway traffic noise, effects which may possibly be included in the FHWA TNM in the future. We hope a continued State pooled-fund study will provide additional support for this. Version 1.1 will also correct some problems and inconveniences and include limited GUI enhancements. Consequently, the final phase-in date is being extended to December 31, 2002.