A systematic approach for arriving at reasonable heights and locations for noise barriers adjacent to railway lines

Communities living adjacent to railway lines and major roadways are demanding much higher transparency and assurance of an equitable outcome in the determination of noise mitigation measures for new and upgraded projects. As a result, it is now necessary for the acoustic consultant to apply methodologies that are fair, reasonable and clearly documented in order to provide communities with the required level of assurance. This paper describes a noise barrier design optimisation methodology that has been applied on recent rail upgrade projects in Sydney Australia. The noise barrier optimisation process uses project related noise goals (LAmax and LAeq) to inform the calculation of the Total Noise Benefit per Unit Area (TNBA) and the Marginal Benefit Value per Unit Area (MBVA). An optimal cost effective region based on the TNBA and MBVA has been proposed. As a result of continuing advances in PC processing power, the population density can also be included in the analysis by modelling all receivers that are potentially "noise affected".