EFFECTIVENESS OF GRASS EMBANKMENTS IN SCREENING HIGH-RISE BUILDINGS FROM HIGHWAY TRAFFIC NOISE

There is a common perception among residents of high-rise buildings facing an expressway that by having a grass embankment in front of the buildings the traffic noise is reduced to some extent. This study shows that the grass embankment would benefit only those living at lower levels, say below the fifth storey. For those living on the tenth storey and above, the traffic noise is about the same regardless of whether the intervening ground is flat or sloped As traffic noise increases as one goes up a building, therefore, in the practical sense, a grass embankment would hot help reduce the traffic noise for high-rise buildings. Also, it is not possible in tropical Singapore to seal windows facing an expressway. Air-conditioning the apartments is too costly, and as most of these high-rise buildings are for the lower-income group, paying for air-conditioning is beyond the occupants' means. Building of noise barriers (which would need to be several kilometres long) along the expressways is not only costly, but also unsightly, and with a barrier height of say 4 m the line of sight for residents living on the fifteenth storey and above is not cut off. Therefore, the only viable way of achieving a desirable traffic noise level is for the buildings to be set further from the kerb of the expressway.