Appendix 4.3 : Assessment of Road Traffic Noise Impact

Example 1 : Benefit of using screens for noise reduction

[ Text Version ]

Example 1 : Benefit of using screens for noise reduction

To achieve noise standard : L10 (1 hour) 70 dB(A)

Land use arrangement A : Separation without effective screening (Figure 1)

Facade noise level from road traffic (from Table 4.2) 

:  78 dB(A)
Noise reduction required (78 dB(A) - 70 dB(A))  

:  8 dB(A)
Separation between source and receiver required
(from Figure A1)  

:  80m (approx.)
Land use arrangement B : Separation with effective screening (Figure 2)

Facade noise level from road traffic (from Table 4.2) 

:  78 dB(A)
Noise reduction required (78 dB(A) - 70 dB(A))  

:  8 dB(A)
Noise reduction due to 30m separation
(from Figure A1)  

:  4.2 dB(A)
Using 15m high screening structures and placed as shown in Figure A2, separation between source and receiver for the remaining required reduction is reduced to

:  30m (approx.)
Remark : The usefulness of screening structures under small source and receiver separation is demonstrated.

Example 2 : Benefit of road alignment consideration for noise improvement

[ Text Version ]

Example 2 : Benefit of road alignment consideration for noise improvement

To achieve noise standard : L10 (1 hour) 70 dB(A)

Alignment A : 
Road alignment fronting noise tolerant buildings offering shielding to receiver


Facade noise level from road traffic (from Table 4.2)  

: 81 dB(A)
Noise reduction due to separation between source and receiver
(from Figure A1) 

:  -5 dB(A)  
Noise reduction due to screening (23°) (from Figure A2) 

:  -9 dB(A)
Overall facade noise level  

:  67 dB(A)
Alignment B : Road alignment being exposed to receiver

Facade noise level from road traffic (from Table 4.2) 

: 81 dB(A)
Noise reduction due to separation between source and receiver
(from Figure A1)  

:  -5 dB(A)
Noise reduction due to screening (90°) (from Figure A2)  

:  -3dB(A)
Overall facade noise level  

: 73 dB(A))
Remark : Given the same separation between source and receiver, Road Alignment A is environmentally better than Road Alignment B. 

Figure A1 : Noise reduction with respect to receiver distance/height

[Text Version]

Figure A1 : Noise reduction with respect to receiver distance/height

 

Figure A2 : Noise reduction with respect to view angle and 
height of screening structure

(Note : This figure is valid for a typical setback distance of 30m)

Figure A2 : Noise reduction with respect to view angle and height of screening structure

back to previous page

  dotted line
   Last revision date : May 2014