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When a model is created in TNM 2.5, it must first be validated to ensure that the model reflects the actual site conditions.
Model validation is the process of comparing actual measured noise levels with noise levels calculated in the TNM 2.5 model. In order to validate the model, noise measurements are taken at several locations along the existing roadway during free-flow traffic conditions. This is because free-flow traffic conditions where high traffic volume is travelling at high speeds produces louder noise levels.
The noise measurements are then compared to the existing conditions model output data. If the noise measurements are within 3 decibels of the model output, the model is considered to be valid.
