Background Information
1.1
This is the first bimonthly Operational Phase
Traffic Noise Monitoring Report prepared by Maunsell Environmental Management
Consultants Ltd. (MEMCL), 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”, 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 by ER.
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. 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.
1.5
In addition to the SPL measurement, relevant
information, including traffic counts,
speed
checks, weather conditions, activities which might
generate extraneous noises were also recorded.
1.6
This Report presents the traffic noise results and
observations of traffic noise monitoring in the bimonthly period from 1 August
to 30 September 2006 just after construction phase EM&A programme ceased on
31 July 2006.
Measurement Time
2.1
Traffic noise measurements were conducted on normal
weekdays during the AM peak traffic hour from 08:00 to 09:00.
Noise Monitoring Locations
(Noise Sensitive Receivers)
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.
2.3
During the pre-monitoring joint site inspection carried
out on 30 August 2006. Some occupants rejected us using their premises for
monitoring and some premises were unoccupied. Traffic noise monitoring was thus
carried out at alternative locations. Essentially, the alternative of monitoring locations
were on the same premise but at different floor or the location which was
adjacent to the proposed location in regard of reflecting the traffic noise
impact on the residents.
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 Tusen (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 Equipment
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
|
Maintenance and Calibration
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.
Noise Measurement
Methodology
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”.
2.9
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.
Traffic Survey
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
|
Ÿ
Noise measurement
Ÿ
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
|
|
M5
|
Jasper Court Block 10 (4/F)
|
|
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
|
Ÿ
Traffic flow survey
Ÿ
Traffic speed measurement
Ÿ
Percentage of heavy vehicles
|
|
M5
|
Roof, Jasper Court Block 10 for M4 - M7
|
|
M9
|
Roof, House 96, Shum Chung Tsuen for M8 - M11
|
General
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, wigwag system and sirens from emergency
vehicles, 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.
Traffic Noise Level
Monitoring Results
3.2
Traffic noise measurements were conducted on three
weekdays during the AM peak traffic hour from 08:00 – 09:00 of 5, 6 and 7 September
2006. 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 are
provided in Table 3.1.
Table 3.1 Traffic
Noise Measurement Results
|
Monitoring Date
|
Weather Condition
|
Monitoring Station
|
Monitoring Period
|
Noise Level (mitigated), L10 dB(A)
|
|
5 September 2006
|
Sunny
|
M1
|
8:00 – 9:00
|
61.0
|
|
M2
|
8:00 – 9:00
|
59.0
|
|
M3
|
8:00 – 9:00
|
62.0
|
|
6 September 2006
|
Fine
|
M4
|
8:00 – 9:00
|
64.0
|
|
M5
|
8:00 - 8:10:34*
|
65.5
|
|
8:00 – 9:00 **
|
77.5
|
|
M6
|
8:00 – 9:00
|
58.5
|
|
M7
|
8:00 – 9:00*
|
60.0
|
|
8:00 – 9:00**
|
65.0
|
|
7 September 2006
|
Cloudy
|
M8
|
8:00 – 9:00
|
60.5
|
|
M9
|
8:00 – 9:00
|
64.5
|
|
M10
|
8:00 – 9:00
|
69.7
|
|
M11
|
8:00 – 9:00
|
63.5
|
Note:
*
Time period with construction noise data erased.
** Time period with nearby construction
activities included.
3.5
Comparison of the edited noise measurement results was
made against the noise standard of 70 dB(A). Tables 3.2 showed that measurement
in L10 at the monitoring stations in comparison with the noise
standard.
Table 3.2 Noise
Level Comparison with the Noise Standard
|
Monitoring Station
|
Monitoring Period
|
Noise Level (mitigated), L10 dB(A)
|
Noise Standard
L10 (1 hour) dB(A)
|
|
M1
|
8:00 – 9:00
|
61.0
|
70
|
|
M2
|
8:00 – 9:00
|
59.0
|
|
M3
|
8:00 – 9:00
|
62.0
|
|
M4
|
8:00 – 9:00
|
64.0
|
|
M5
|
8:00 - 8:10:34*
|
65.5
|
|
8:00 – 9:00**
|
77.5
|
|
M6
|
8:00 – 9:00
|
58.5
|
|
M7
|
8:00 – 9:00*
|
60.0
|
|
8:00 – 9:00**
|
65.0
|
|
M8
|
8:00 – 9:00
|
60.5
|
|
M9
|
8:00 – 9:00
|
64.5
|
|
M10
|
8:00 – 9:00
|
69.7
|
|
M11
|
8:00 – 9:00
|
63.5
|
Note:
*
Time period with construction noise data erased.
** Time period with nearby construction
activities included.
Road Condition and Traffic
Survey
3.6
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.
3.7
The traffic conditions along Yuen Long Highway were
normal and there was no traffic congestion during the monitoring periods.
3.8
The percentage of heavy vehicle (HV) was
significantly higher than that of light vehicle (LV). Details of the traffic flow and the
percentage of heavy vehicle are provided in Table 3.3.
Table 3.3 Traffic
Flow of Yuen Long Highway
|
Monitoring Station
|
LV
|
HV
|
Total Flow
|
Percentage of HV
|
|
M1
|
2288
|
2784
|
5072
|
54.9
|
|
M2
|
2288
|
2784
|
5072
|
54.9
|
|
M3
|
2288
|
2784
|
5072
|
54.9
|
|
M4
|
2436
|
3004
|
5440
|
55.2
|
|
M5
|
2116
|
2684
|
4800
|
55.9
|
|
M6
|
1668
|
2560
|
4228
|
60.5
|
|
M7
|
1668
|
2560
|
4228
|
60.5
|
|
M8
|
2276
|
2972
|
5248
|
56.6
|
|
M9
|
2276
|
2972
|
5248
|
56.6
|
|
M10
|
2276
|
2972
|
5248
|
56.6
|
|
M11
|
2276
|
2972
|
5248
|
56.6
|
Notes:
HV represents Heavy Vehicle
LV represents Light
Vehicle
3.9
The traffic speeds along Yuen Long Highway were estimated
concurrently with the noise measurement. Table 3.4 provides a summary of
averaged traffic speed monitoring results.
Table 3.4 Traffic
Speed Measurement
|
Monitoring Station
|
Speed (km/hr)
|
|
M1
|
80.09
|
|
M2
|
80.09
|
|
M3
|
80.09
|
|
M4
|
73.72
|
|
M5
|
73.72
|
|
M6
|
73.72
|
|
M7
|
73.72
|
|
M8
|
81.26
|
|
M9
|
81.26
|
|
M10
|
81.26
|
|
M11
|
81.26
|
4.1
As shown in Table 3.2, in the monitoring
station at M5, noise measurement at station M5 was significantly interrupted by
construction noise in the vicinity of the monitoring location from 08:10:35 –
09:00. There was insufficient time
to measure one L10 (1 hr) at this AM peak traffic flow period. The noise
level without construction activity was 65.5 dB(A); i.e. below the noise
standard of 70 dB(A). The results indicated the noise level in which the
construction activities included was exceeded with the noise standard by 7.5
dB(A).
4.2
The noise levels recorded at the remaining nine
monitoring stations were below the noise standard in this reporting period. In the monitoring station at M7, noise
measurement at station M7 was significantly interrupted by construction noise
in the vicinity of the monitoring location. There was insufficient time to measure
one L10 (1 hr) at this AM peak traffic flow period. The results
indicated the noise level with and without construction activity were below the
noise standard.
Predicted Noise Levels under
the Traffic Flow Condition in 2021
4.3
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
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”, for the worst case scenario, the traffic noise levels was
predicted to occur in year 2021.
4.5
Slip road segment was in front of M5 with different
traffic flow and speed when comparing with those at Yuen Long Highway. Therefore, the correction factor
evaluation method could not be applied for the measured noise level at M5.
Nonetheless, the measured traffic noise levels, with treated data were directly
compared with the noise standard of 70 dB(A).
4.6
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
|
4.7
The correction factors for each monitoring period
were evaluated and summarized in Table 4.2.
Table 4.2 Correction
Factor for Different Monitoring Period
|
Sensitive Receiver
|
Correction Factor dB(A)
|
|
M1
|
3.2
|
|
M2
|
3.2
|
|
M3
|
3.2
|
|
M4
|
3.2
|
|
M6
|
4.0
|
|
M7
|
4.0
|
|
M8
|
2.8
|
|
M9
|
2.8
|
|
M10
|
2.8
|
|
M11
|
2.8
|
4.8
Under the designed traffic condition in 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 Corrected Noise Level
|
Sensitive Receiver
|
Measured Noise Level, L10
dB(A)
|
Corrected Noise Level, L10
dB(A)*
|
Predicted Noise Level
(mitigated), L10 dB(A) in Year 2021*
|
|
M1
|
61.0
|
64.2
|
65
|
|
M2
|
59.0
|
62.2
|
66
|
|
M3
|
62.0
|
65.2
|
68
|
|
M4
|
64.0
|
67.2
|
64
|
|
M6
|
58.5
|
62.5
|
66
|
|
M7
|
60.0 **
|
64.0
|
61
|
|
65.0 ***
|
69.0
|
|
M8
|
60.5
|
63.3
|
64
|
|
M9
|
64.5
|
67.3
|
69
|
|
M10
|
69.7
|
72.5
|
65
|
|
M11
|
63.5
|
66.3
|
70
|
Note
*
Corrected by traffic flow,
speed and percentage of heavy vehicles.
**
Time period with construction noise data erased.
*** Time period with nearby construction
activities included.
5.1
Traffic noise measurements were conducted on three
weekdays during the AM peak traffic hour from 08:00 to 09:00 of 5, 6 and 7 September
2006. The weather conditions were sunny, fine or cloudy respectively. 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
Sound pressure levels, in L10 (1hr),
were recorded at the 11 designated monitoring locations. Results indicated that
all measurement L10 (1 hour) levels were below the noise standard of
70 dB(A) except the monitoring locations at M5 (which was due to the construction
noise in the vicinity).
5.4
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.
The corrected noise levels were also compared with the predicted noise levels.
5.5
All corrected noise levels for the ten monitoring
locations in the year 2021 did not exceed the noise standard of 70 dB(A) under the
predicted traffic condition in 2021 except for monitoring location at M10 after
applying the appropriate correction factor.
1.
Department of Transport,
UK (1988), Calculation
of Road Traffic Noise
2.
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
