3. LOOK-UP TABLES DATA

This section contains the TNM Version 2.5 Look-Up Tables in their entirety. Section 3.1 presents hourly equivalent sound level data (L_Aeq1h) for geometries with no barrier. Section 3.2 presents L_Aeq1h data for geometries with a barrier 10 m from the centerline of the roadway. Section 3.3 presents L_Aeq1h data for geometries with a barrier 30 m from the centerline of the roadway.

Each tabulated value represents the L_Aeq1h for 1000 vehicle pass-bys. To combine L_Aeq1h values for mixed traffic volumes, the following equation may be used* :

Equation 1. Combine L_Aeq1h values for mixed traffic volumes.

where:

• L_Aeq1h is the hourly equivalent sound level taking into account all input parameters;
• V_Auto is the volume of automobile traffic;
• L_Aeq1h(Auto) is the hourly equivalent sound level associated with automobiles, interpolated from the appropriate look-up table for the appropriate input parameters;
• V_MT is the volume of medium truck traffic;
• L_Aeq1h(MT) is the hourly equivalent sound level associated with medium trucks, interpolated from the appropriate look-up table for the appropriate input parameters;
• V_HT is the volume of heavy truck traffic;
• L_Aeq1h(HT) is the hourly equivalent sound level associated with heavy trucks, interpolated from the appropriate look-up table for the appropriate input parameters;
• V_Bus is the volume of bus traffic;
• L_Aeq1h(Bus) is the hourly equivalent sound level associated with buses, interpolated from the appropriate look-up table for the appropriate input parameters;
• V_MC is the volume of motorcycle traffic; and
• L_Aeq1h(MC) is the hourly equivalent sound level associated with motorcycles, interpolated from the appropriate look-up table for the appropriate input parameters.

For example, to compute the barrier insertion loss in the sample case presented in Figure 11:

1. First, compute the L_Aeq1h with a barrier present (at a distance of 10 m from the center of the roadway) by retrieving the L_Aeq1h data for each vehicle type from the appropriate Look-Up Tables:
   • For a 30-m receiver, the L_Aeq1h contribution from automobiles traveling at 80 km/h (Table 22) is 50.7 dB;
   • For a 30-m receiver, the L_Aeq1h contribution from medium trucks traveling at 70 km/h (Table 40) is 57.6 dB;
   • For a 30-m receiver, the L_Aeq1h contribution from heavy trucks traveling at 65 km/h (Table 58, interpolated between 60 and 70 km/h) is 61.5 dB;
   • For a 30-m receiver, the L_Aeq1h contribution from buses traveling at 70 km/h (Table 76) is 57.5 dB; and
   • For a 30-m receiver, the L_Aeq1h contribution from motorcycles traveling at 80 km/h (Table 94) is 62.2 dB.
   • Then, substitute the above L_Aeq1h values and the vehicle volumes (from Figure 11) into the following equation:

Equation 2. Computer L_Aeq1h with a barrier present (at a distance of 10 m from the center of the roadway)

2. Next, compute the L_Aeq1h without a barrier by retrieving the L_Aeq1h data for each vehicle type from the appropriate Look-Up Tables:
   • For a 30-m receiver, the L_Aeq1h contribution from automobiles traveling at 80 km/h (Table 2) is 61.0 dB;
   • For a 30-m receiver, the L_Aeq1h contribution from medium trucks traveling at70 km/h (Table 4) is 66.9 dB;
   • For a 30-m receiver, the L_Aeq1h contribution from heavy trucks traveling at 65 km/h (Table 6, interpolated between 60 and 70 km/h) is 70.75 dB;
   • For a 30-m receiver, the L_Aeq1h contribution from buses traveling at 70 km/h (Table 8) is 67.2 dB; and
   • For a 30-m receiver, the L_Aeq1h contribution from motorcycles traveling at 80 km/h (Table 10) is 70.3 dB.
   • Then, substitute the above L_Aeq1h values and the vehicle volumes (from Figure 11) into the following equation:

Equation 3. Compute the L_Aeq1h without a barrier

3. The resultant barrier insertion loss is computed by algebraically subtracting the with-barrier LAeq1h from the without-barrier LAeq1h:

   Barrier Insertion Loss = 69.5 - 60.2 = 9.3 dB