FHWA Traffic Noise Model

FHWA TNM Version 2.5 Look-Up Tables

Since the release of the FHWA TNM, Version 2.5 contained changes in the acoustical calculations, new look-up tables needed to be generated. The result was new Windows-based program entitled "FHWA TNM Version 2.5 Look-Up Tables". This program provides highway traffic noise analysts with a screening tool to be used in simple applications of the FHWA TNM.

The FHWA TNM Version 2.5 Look-Up Tables provide a reference of pre-calculated FHWA TNM results for simple highway geometries. The calculations are for an infinitely long, straight roadway over flat ground, with a receiver set at a height of 1.5 m above the ground. If desired, an infinitely long straight barrier may also be included in the calculations. Specifically, the tables contain results for the following parameters:

• Five vehicle types (automobiles, medium trucks, heavy trucks, buses, and motorcycles) at speeds of 0 to 130 kilometers per hour (km/h) in 10 km/h increments;
• Sound level propagation over acoustically hard or soft terrain;
• A single wall barrier (if desired) at a height of between 2 and 10 m, located at a distance of either 10 or 30 m from the centerline of the roadway; and
• Receivers at distances from 10 to 300 m in 10 m increments from the centerline of the roadway.

While the Look-Up Table data exist in the above fixed parameter increments, the software version of the look-up tables will interpolate within these increments. For example, the Look-Up Table contains data for receivers at distances 10 to 300 m in 10 m increments while the software will interpolate data at any distance within 10 to 300 m. The software will not, however, extrapolate values beyond the range of the fixed parameters. This program uses the FHWA TNM Version 2.5 Look-Up Tables to determine sound levels associated with a particular geometry.

The previously distributed report, "FHWA Traffic Noise Model Look-Up Tables" and its accompanying DOS program TNMLOOK are superseded.

The following documents are associated with the FHWA TNM Version 2.5 Look-Up Tables:

1. FHWA Traffic Noise Model Version 2.5 Look-Up Tables Windows Program, click here to download - setup.exe (16Mb).
2. FHWA Traffic Noise Model® Version 2.5 Look-up Tables (HTML ) or (PDF - 1.5Mb) User's Guide.

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