The objectives of the experiment are:
i. To determine the traffic noise level at L10 (i.e. the noise level which are exceeded by 10% of the specified time). ii. The L10 is then compared with that obtain from predicted method. iii. A statistical test is performed to find whether there is any significant difference between the two results at a 5% level of significance.
Apparatus
Data logging sound level meter, tripod, distance measurement tape and traffic counter.
Procedure
The procedures of the experiment are as follows:
i. According to their manuals specifications , the recorder was positioned and set as steps in (ii) to (vi) for the purpose of measuring road traffic noise. ii. The meter is powered and the desired Time response (Fast or Slow) and Frequency Weighting (A or C) was selected. iii. The desired range was selected manually or enable the Auto range function (Range: 30 – 130 dB) iv. The instrument was hold comfortably in hand or positioned on tripod. The microphone was pointed towards the noise source, the sound pressure level will be displayed on the meters LCD display.
v. By pressing the MAX key, MAX(maximum hold) mode was selected where the instrument captures and holds the maximum noise level reading on the display. To clear the MAX reading, press the MAX key again. vi. Sample for 30 minutes was taken using table in Figure 4.0 and later analyze to determine the estimated L10 value. vii. When not in use, turned off the instrument and removed the battery. viii. All the measurement required was recorded for the traffic noise prediction, such as distances of point source to receive, traffic volumes and their compositions in Figure 4.1. With these information together with the manual, ‘Calculations of Road Traffic Noise, 1975 HMSO’, the predicted value of L10 can be