DEUFRAKO: calculation of LAeq and Lden
DEUFRAKO: P2RN
Prediction and Propagation of rolling noise
LAeq

Method

The calculation of the LAeq based on a method developed by Bérengier et al. [1]. The following input parameter are needed:

LAeq

The figure above shows the principle of the calculation of the LAeq. First the LAeq for a single vehicle, a reference period T (typically 1 hour) at a reference receiver Rref (distance source↔receiver: Dref) is calculated:

LAeq

In a second step the LAeq at a distance Dmeas for a single vehicle is calculated as follows:

LAeq

All these calculations are made for passenger cars as well as for heavy trucks. To compute the LAeq depending on the traffic volume for each hour the calculated LAeq,T(v,D) must sum up logarithmical:

LAeq

where npc and nht are, respectivly, the number of passenger cars and heavy trucks in the traffic flow during the period T. LAeq(pc) and LAeq(ht) are the LAeq for one representative vehicle of each family on the reference period one hour.

Afterwards the Lden is calculated from the LAeq:

LAeq

References

[1] M. Bérengier, Y. Pichaud, J.-F. Le Fur, Effect of low-noise pavements on traffic noise propagation over large distances: influence of ground and atmospheric conditions, Internoise 2000, Nice, 2000.
[2] ISO 11819-1, Acoustics: Method for measuring the influence of road surfaces on traffic noise - Part 1: Statistical pass-by method, 1996

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