1.1
This is the sixth bimonthly Operational Phase
Traffic Noise Monitoring Report prepared by ENSR Asia (HK) Ltd. (ENSR), (formerly
Maunsell Environmental Management Consultants Ltd), the designated
Environmental Team (ET), for the Project “Widening of Yuen Long Highway Between
Tan Kwai Tsuen and Shap Pat Heung Interchange”. This report presents the results of
operational traffic noise level at noise sensitive receivers (NSRs) identified
in the Traffic Noise Monitoring Plan. The objective of this report is to assess
whether the level of traffic noise measured at the designated NSRs are
environmental compliance after the mitigation measures (noise barrier) was
implemented.
1.2
In accordance with the “Final Environmental Impact
Assessment Report for Preliminary Design and Ground Investigation for Widening
of Yuen Long Highway between Lam Tei and Shap Pat Heung Interchange”[1], in order to assess the effectiveness of the proposed barriers, traffic
noise monitoring is required to be carried out at representative NSRs within
one year of the road opening. A Traffic Noise Monitoring Plan (Version No.1)
was prepared based on the requirement stipulated in the Environmental Permit
No.EP-141/2002 Clause 5.1 and was submitted to EPD.
1.3
Pre-monitoring joint site inspection was carried
out on 30 August 2006
by the Engineer Representative (ER), the Contractor and ET to determine the
exact location of stations for the monitoring.
1.4
In accordance with the Traffic Noise Monitoring
Plan, the noise measurements will be conducted at 11 designated monitoring
locations as shown in Figure 1.1. However, at monitoring station M5
(Jasper Court), since the property management company at Jasper Court rejected
us using the premise to conduct the traffic noise monitoring and there was no
other alternative location for relocation in regard of reflecting the traffic
noise impact on the station at M5, the traffic noise monitoring at Station M5
was not conducted in this bimonthly monitoring.
1.5
The objectives of the measurements were to obtain
sound pressure levels (SPL), in L10 (1-hour), as measured at the
sensitive receivers during the peak traffic periods of a day and check if they
complied with specified noise standard.
1.6
In addition to the SPL measurement, relevant
information, including traffic counts,
speed
checks, weather conditions, activities which might
generate extraneous noises were also recorded.
1.7
This Report presents the traffic noise results and observations
of traffic noise monitoring in the bimonthly period from 1 June 2007 to 31 July
2007.
2
MEASUREMENT
METHODOLOGY
2.1
Traffic noise measurements were conducted on normal
weekdays during the AM peak traffic hour from 08:00 to 09:00.
2.2
Noise measurements were conducted at eleven
designated monitoring locations according to the Traffic Noise Monitoring Plan
which was shown in Figure 1.1. Table 2.1 describes these monitoring
stations.
Table 2.1 Noise
Monitoring Locations (Sensitive Receivers)
|
NSR ID*
|
Monitoring Station
|
Monitoring Station Location
|
Predicted Noise Level
(mitigated), L10 dB(A) in Year 2021^
|
Noise Standard
L10
(peak hour) (dB(A))
|
|
93
|
M1
|
Village
House in Tan Kwai Tsuen (1/F)**
|
65
|
70
|
|
17
|
M2
|
Village
House near Great
Garden (1/F)**
|
66
|
|
|
M3
|
Village
House in Tai Tao Village (1/F)***
|
68 !
|
|
|
M4
|
Village
House beside Tong Tai Road (1/F)***
|
64 @
|
|
13
|
M5##
|
Jasper
Court Block 10 (4/F)
|
70
|
|
24
|
M6
|
Village
House in Lam Hau Tsuen (1/F) **
|
66
|
|
88
|
M7
|
Village
House in Lam Hau Tsuen (1/F)**
|
61
|
|
|
M8
|
Village
House beside Kung Um Road (1/F) ***
|
64 #
|
|
|
M9
|
Sham
Chung Tsuen (3/F)***
|
69 %
|
|
|
M10
|
Shung
Ching San Tsuen (1/F)***
|
65 +
|
|
26
|
M11
|
Village
House near Kung Um Road (3/F)
|
70
|
* Noise Sensitive
Receiver (NSR) ID number used in the Final EIA Report.
** Monitoring
location was allocated to different floor.
***
Monitoring location was allocated to another premise nearby.
! Predicted
noise level was obtained from NSR ID 57.
@ Predicted
noise level was obtained from NSR ID 20.
# Predicted noise level was obtained from NSR ID 79.
% Predicted
noise level was obtained from NSR ID 31.
+ Predicted
noise level was obtained from NSR ID 65.
^ Various types of noise
barriers were built as mitigation measures.
## Noise monitoring was not conducted in this bimonthly
monitoring.
2.4
The Sound Level Meters to be used for the
monitoring will comply with the International Electrotechnical Commission
Publications 651:1979 (Type 1) and 804:1985 (Type 1). Any other noise measuring
and analysis instrument used will be of comparable professional quality. The
instrumentation to be used for the noise monitoring is given Table 2-2.
Table 2.2 Traffic
Noise Monitoring Equipment
|
Manufacturer
|
Description
|
|
Integrating Sound Level Meter
|
B&K 2238
|
|
Calibrator
|
B&K 4231
|
2.5
The sound level meter will be calibrated using a
Bruel and Kjaer Sound Level Calibrator Type 4231 for 94dB at 1kHz, prior to and
after each set of measurements. The results of the calibration will be recorded
on the field data sheet.
Measurement results will be discarded if the calibration before and
after does not agree to within 1dB(A) and measurement will be taken until this
condition is fulfilled.
2.6
The noise measurements were conducted to obtain one
set of A-weighted L10 (1 hour) sound pressure level during the AM
peak traffic hour in one-hour monitoring period at each designated sensitive
receiver.
2.7
The noise measurement point was at a point 1m from the exterior of the sensitive receiver
building facades and was at a position at least 1.2m above ground of the sensitive receiver level.
2.8
Noise measurements were made in accordance with
Section III of the “Calculation of Road Traffic Noise (CRTN), 1998” [2].
2.9
As recommended in CRTN, a façade effect correction
factor of 2.5 dB(A) will be further added to the measured noise level if the
monitoring is carried out in a free field condition.
2.10
Statistical results such as Lmax, Lmin,
Leq and L90 were also obtained for reference purpose.
2.11
The wind speed was frequently checked with a
portable wind meter.
2.12
Observations were recorded when intrusive noise was
unavoidable.
2.13
Noise monitoring was cancelled in the presence of
fog, rain, wind with a steady speed exceeding 5
m/s, or wind with gusts exceeding 10 m/s.
2.14
Traffic surveys were conducted concurrently with
the noise measurement for the sections of Yuen Long Highway in front of the
representative sensitive receivers.
2.15
Background information, including weather
conditions and noise sources other than traffic along Yuen Long Highway, was
recorded at each sensitive receiver.
The traffic survey included monitoring of traffic flow, percentage of
heavy and light vehicles and average traffic speed.
2.16
Since there were slip roads dividing the highway
into three sections with different traffic conditions, traffic surveys were
conducted for three sections separately.
2.17
Details of the noise measurement and traffic survey
locations as well as relevant activities are presented in Table 2.3.
Table 2.3 Details
of the Noise Measurement and Traffic Survey locations
|
Monitoring Station
|
Monitoring Station Location
|
Type of Measurement
|
Nature
|
Activities
|
|
M1
|
Village House in Tan Kwai Tsuen (1/F)
|
Façade
|
Noise Sensitive Receiver
|
Noise measurement
Recording of noise sources other than traffic
along Yuen Long Highway
|
|
M2
|
Village House near Great Garden (1/F)
|
|
M3
|
Village House in Tai Tao Village (1/F)
|
Free Field
|
|
M4
|
Village House beside Tong Tai Road (1/F)
|
Façade
|
|
M6
|
Village House in Lam Hau Tsuen (1/F)
|
|
M7
|
Village House in Lam Hau Tsuen (1/F)
|
|
M8
|
Village House beside Kung Um Road (1/F)
|
|
M9
|
Sham Chung Tusen
(3/F)
|
|
M10
|
Shung Ching San Tsuen (1/F)
|
|
M11
|
Village House near Kung Um Road (3/F)
|
|
M3
|
Hill, near monitoring station for M1 - M3
|
Not Applicable
|
Traffic Survey Location
|
Traffic flow survey
Traffic speed measurement
Percentage of heavy vehicles
|
|
-
|
Adjacent to Highway near Lam Hau Tsuen M4, M6 &
M7*
|
|
M9
|
Roof, House 96, Shum Chung Tsuen for M8 - M11
|
* Alternative location was
used for traffic counting at M4, M6 and M7 in this report period
3.1
During the course of noise monitoring, road traffic
along Yuen Long Highway was the major noise source. Noise data was continuously
recorded by sound level meter at an interval of 1 second. Other sources
included community noise, dog barking, traffic on the local road, nearby
construction activities, and etc. These activities were recorded during the
monitoring events and these extraneous noises were not taken into calculation
of the traffic noise level.
3.2
Traffic noise measurements were conducted on three
weekdays during the AM peak traffic hour from 08:00 – 09:00 on 10, 12 and 24 July
2007. Random check of wind speed at the monitoring station showed that it was
below 5 m/s.
3.3
There were some activities, which generated
extraneous noises, and these activities were recorded during the monitoring
events. The noise data was recorded by the sound level meter. Based on the site
records, non-traffic related data was neglected, in order to indicate the
traffic noise level of Yuen Long Highway.
3.4
The summaries of traffic noise levels recorded and comparison
was made against the noise standard of 70 dB(A). Table 3.1 shows the
traffic noise measurement result in comparison with the noise standard.
Table 3.1 Traffic Noise Measurement Results and
Comparison with Noise Standard
|
Monitoring Date
|
Weather Condition
|
Monitoring Station
|
Noise Level (Mitigated), L10 dB(A)
|
Noise Standard
L10 (1 hour) dB(A)
|
|
10 July 2007
|
Sunny
|
M1
|
60.5
|
70
|
|
M2
|
57.4
|
|
M3
|
63.9
|
|
24 July 2007
|
Sunny
|
M4
|
63.8
|
|
M6
|
57.0
|
|
M7
|
58.4
|
|
12 July 2007
|
Sunny
|
M8
|
59.5
|
|
M9
|
64.3
|
|
M10
|
63.9
|
|
M11
|
63.8
|
3.5
As noted during the course of monitoring, the road
surfaces of Yuen Long Highway were asphalt paved. No obstruction or damage was
noted from the road surfaces.
3.6
The traffic conditions along Yuen Long Highway were
normal and there was no traffic congestion during the monitoring periods.
3.7
Details of the traffic flow and the percentage of
heavy vehicle are provided in Table 3.2.
Table 3.2 Traffic
Flow of Yuen Long Highway
|
Monitoring Station
|
LV
|
HV
|
Total Flow
|
Percentage of HV
|
|
M1
|
2120
|
2884
|
5004
|
57.6
|
|
M2
|
2120
|
2884
|
5004
|
57.6
|
|
M3
|
2120
|
2884
|
5004
|
57.6
|
|
M4
|
2040
|
2792
|
4832
|
57.8
|
|
M6
|
2040
|
2792
|
4832
|
57.8
|
|
M7
|
2040
|
2792
|
4832
|
57.8
|
|
M8
|
2676
|
2376
|
5052
|
47.0
|
|
M9
|
2676
|
2376
|
5052
|
47.0
|
|
M10
|
2676
|
2376
|
5052
|
47.0
|
|
M11
|
2676
|
2376
|
5052
|
47.0
|
Notes:
HV represents Heavy Vehicle
LV represents Light
Vehicle
3.8
The traffic speeds along Yuen Long Highway were
estimated concurrently with the noise measurement. Table 3.3 provides a
summary of averaged traffic speed monitoring results.
Table 3.3 Traffic
Speed Measurement
|
Monitoring Station
|
Speed (km/hr)
|
|
M1
|
88.0
|
|
M2
|
88.0
|
|
M3
|
88.0
|
|
M4
|
84.2
|
|
M6
|
84.2
|
|
M7
|
84.2
|
|
M8
|
79.5
|
|
M9
|
79.5
|
|
M10
|
79.5
|
|
M11
|
79.5
|
4
DISCUSSION
4.1
The noise levels recorded at the 10 monitoring
stations were all below the noise standard in this reporting period.
4.2
According to the Environmental Impact Assessment
Final Report for the Project, “Agreement No. CE 98/98 - Preliminary Design and
Ground Investigation for Widening of Yuen Long Highway Between Lam Tei and Shap
Pat Heung Interchange” [1], for the worst case scenario, the traffic
noise levels was predicted to occur in year 2021.
4.3
Based on the Traffic Noise Monitoring Plan (Version
No.1) submitted to EPD. The predicted noise level under the traffic flow
condition in 2021 was in accordance with Section III of the “Calculation of
Road Traffic Noise (CRTN), 1988”
[2] for adjustment to the measured traffic noise level by adding a
correction factor and for comparison with prediction from the CRTN. This will include the traffic flow, percentage
of heavy vehicles, and an average vehicular speed. The following equation
extracted from the CRTN was adopted to correct the measured noise level in
consideration of the differences between the measured traffic flow and the
predicted traffic flow in the Final EIA Report.
* Correction Factor = 
Where Q’
is predicted traffic flow by using the CRTN noise model,
V’ is predicted traffic speed by using the
CRTN noise model,
p’ is predicted percentage heavy vehicle by using
the CRTN noise model,
Q is measured traffic flow during the
traffic noise monitoring event,
V is measured traffic speed during the
traffic noise monitoring event,
p is measured percentage heavy vehicle
during the traffic noise monitoring event.
4.4
The predicted noise levels at the sensitive
receivers, M1 – M4, M6 – M11 are estimated based on the equation from CRTN.
4.5
Detailed traffic conditions in year 2021 are
summarized in the Table 4.1.
Table 4.1 Predicted
2021 Peak Hour Traffic Data
|
Noise Monitoring Location
|
Traffic Flow (Nr/hr)
|
% of HV
|
Traffic Speed (km/hr)
|
|
M1 – M4, M6 – M11
|
10,900
|
53
|
80
|
4.6
The correction factors for each monitoring location
were evaluated and summarized in Table 4.2.
Table 4.2 Correction
Factor for Monitoring Stations M1 – M4, M6 – M11
|
Sensitive Receiver
|
Correction Factor dB(A)
|
|
M1
|
2.6
|
|
M2
|
2.6
|
|
M3
|
2.6
|
|
M4
|
3.0
|
|
M6
|
3.0
|
|
M7
|
3.0
|
|
M8
|
3.7
|
|
M9
|
3.7
|
|
M10
|
3.7
|
|
M11
|
3.7
|
4.7
Under the designed traffic condition in Year 2021,
the predicted noise levels as received at the sensitive receivers, M1 – M4, M6
– M11 are estimated and shown in Table 4.3.
Table 4.3 Measured
and Normalized Noise Level
|
Sensitive Receiver
|
Measured Noise Level, L10
dB(A)
|
Normalized Noise Level, L10
dB(A)*
|
Predicted Noise Level
(Mitigated), L10 dB(A) in Year 2021*
|
|
M1
|
60.5
|
63.1
|
65
|
|
M2
|
57.4
|
60.0
|
66
|
|
M3
|
63.9
|
66.5
|
68
|
|
M4
|
63.8
|
66.8
|
64
|
|
M6
|
57.0
|
60.0
|
66
|
|
M7
|
58.4
|
61.4
|
61
|
|
M8
|
59.5
|
63.2
|
64
|
|
M9
|
64.3
|
68.0
|
69
|
|
M10
|
63.9
|
67.6
|
65
|
|
M11
|
63.8
|
67.5
|
70
|
Note
*
Corrected by traffic flow, speed and percentage of heavy vehicles.
5.1
Traffic noise measurements were conducted on three
weekdays during the AM peak traffic hour from 08:00 to 09:00 on 10, 12 and 24 July
2007. The weather conditions during the monitoring days were sunny. The traffic conditions, including
traffic flows, type of vehicles and average traffic speeds were also monitored
during the monitoring events.
5.2
Activities which generated extraneous noise were
recorded, and these irrelevant noise data were not taken into the evaluation of
traffic noise levels.
5.3
At monitoring station M5 (Jasper Court), since the
property management company at Jasper Court rejected us using the premise to
conduct the traffic noise monitoring and there was no other alternative
location for relocation in regard of reflecting the traffic noise impact on the
station at M5, the traffic noise monitoring at Station M5 would not be
conducted in this bimonthly monitoring.
5.4
Sound pressure levels, in L10 (1hr),
were recorded at the 10 designated monitoring locations. Results indicated that
all measurement L10 (1 hour) levels were below the noise standard of
70 dB(A).
5.5
The traffic flow, speed and percentage of heavy
vehicles were recorded during each monitoring period. The correction factors for M1 - M4 and
M6 - 11 were evaluated based on the differences of traffic conditions between
these noise measurement events and the predicted traffic condition in Year
2021.
5.6
The normalized noise levels were also compared with
the predicted noise levels. All normalized noise levels for the eleven
monitoring locations in the year 2021 did not exceed the noise standard of 70
dB(A) under the predicted traffic condition in 2021.
1.
Scott Wilson (Hong Kong)
Ltd. (2001), Agreement No. CE 98/98 - Preliminary Design and Ground Investigation
for Widening of Yuen Long Highway Between Lam Tei and Shap Pat Heung Interchange
- Environmental Impact Assessment Final Report
2.
Department of Transport,
UK (1988), Calculation
of Road Traffic Noise
