• Measured light vehicle noise reduction by hedges

      Van Renterghem, T.; Attenborough, K.; Maennel, M.; Defrance, J.; Horoshenkov, Kirill V.; Kang, J.; Bashir, I.; Taherzadeh, S.; Altreuther, B.; Khan, Amir; et al. (2014-04)
      The acoustical effects of hedges result from a combination of physical noise reduction and their influences on perception. This study investigates the physical noise reduction so as to enable estimation of its relative importance. Different in-situ methods have been used to measure noise shielding by hedges. These include a statistical pass-by experiment where the real insertion loss of a hedge could be measured, three controlled pass-by experiments using a reference microphone at close distance, and transmission loss measurements using a point source. Thick dense hedges are found to provide only a small total A-weighted light vehicle noise reduction at low speeds. Measured insertion losses range from 1.1 dBA to 3.6 dBA. The higher noise reductions are found to be associated with an increased ground effect.
    • Toolbox from the EC FP7 HOSANNA project for the reduction of road and rail traffic noise in the outdoor environment

      Forsséna, J.; Hornikx, M.; Van Der Aa, B.; Nilsson, M.; Rådsten-Ekmanc, M.; Defrance, J.; Jean, P.; Koussa, F.; Maillard, J.; Van Maercke, D.; et al. (2014)
      This paper offers a brief overview of innovative methods for road and rail traffic noise reduction between source and receiver. These include using new barrier designs, planting of trees, treatments of ground and road surfaces and greening of building façades and roofs using natural materials, like vegetation, soil and other substrates in combination with recycled materials and artificial elements. The abatements are assessed in terms of numerically predicted sound level reductions, perceptual effects and cost–benefit analysis. Useful reductions of noise from urban roads and tramways are predicted for 1-m-high urban noise barriers and these are increased by adding inter-lane barriers. A 3 m wide 0.3 m high lattice ground treatment, a carefully planted 15-m-wide tree belt and replacing 50 m of paved areas by grassland are predicted to give similar reductions. Tree belts are shown to be very cost-effective and combining tall barriers with a row of trees reduces the negative impact of wind. Green roofs may significantly reduce the noise at the quiet side of buildings.