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© Renzo Tonin & Associates (NSW) Pty Ltd Central Coast Highway Upgrade - Matcham Road to Ocean View Drive

Environmental Acoustics Team (Major Projects) REF - Noise Impact Assessment Report

TD780-01F03 (rev 3) REF Report.doc Parsons Brinckerhoff

14 November 2008 4

3 ROAD TRAFFIC NOISE ASSESSMENT

3.1 Traffic Noise Criteria

Road traffic noise impacts addressed in this report are assessed in accordance with the NSW

Environmental Criteria for Road Traffic Noise (ECRTN, NSW Environment Protection Authority

1999) and the RTA’s Environmental Noise Management Manual (ENMM, 2001). The Central

Coast Highway is classed as an arterial road in that it handles through traffic bound for another

locality and has characteristically heavy and continuous traffic flows.

This project involves upgrading the existing arterial road to incorporate a dual carriageway.

According to the ENMM, this project does not constitute a ‘new road traffic noise source’

because the road is not a new road and does not produce noise to receptors from a different

direction. This project is essentially an expansion of an existing arterial road to increase traffic

carrying capacity and there is already an existing road traffic noise exposure greater than

55dB(A) LAeq(15hr) and/or 50dB(A) LAeq(9hr). Therefore, the “redeveloped road” criteria as set out

in the ECRTN apply. The noise criteria for redevelopment of an existing arterial road are as

follows.

Table 3.1 - NSW Environmental Criteria for Road Traffic Noise

Criteria, dB(A) Type of Development Day Night

Where Criteria are Already Exceeded

3. Redevelopment of existing freeway/arterial road

LAeq(15hr) 60 LAeq(9hr) 55 In all cases, the redevelopment should be designed so as not to increase existing noise levels by more than 2 dB.

Where feasible and reasonable, noise levels from existing roads should be reduced to meet the noise criteria. In many instances this may be achievable only through long-term strategies such as improved planning, design and construction of adjoining land use developments; reduced vehicle emission levels through new vehicle standards and regulations of in-service vehicles; greater use of public transport; and alternative methods of freight haulage

Sensitive Land Use Developments

The ECRTN also sets guidelines for the assessment of traffic noise on sensitive land uses such

as schools, hospitals, places of worship and recreation areas. There are no sensitive land uses

within the study area, thus noise goals are not required to be set for these types of

developments.




14 November 2008 Page 15

3.2 Traffic Flow and Composition Summary

3.2.1 Existing Traffic Volumes along the Central Coast Highway

A traffic survey was undertaken by Austraffic along the Central Coast Highway between

Matcham Road and Ocean View Drive. This survey was performed between Friday 27 June to

Friday 4 July 2008. Traffic counts were undertaken at two locations, between Matcham Rd and

Willoughby Rd and between Willoughby Rd and Ocean View Drive. The following tables show

traffic volumes and compositions of those two sections, in terms of daytime (15hr) and night-

time (9hr) data, averaged over the seven day measurement period.

Table 3.2 – Traffic volumes along the Central Coast Highway – 2008

Eastbound Westbound

Road Section Period Volume

Per Cent Heavy

Volume Per Cent Heavy

Day: 7am – 10pm 9,889 4 9,517 4 Central Coast Highway between Matcham Rd and Willoughby Rd Night: 10pm – 7am 666 5 1,175 5

Day: 7am – 10pm 8,676 4 8,817 3 Central Coast Highway between Willoughby Rd and Ocean View Dr Night: 10pm – 7am 692 5 1,068 4

3.2.2 Existing Traffic Volumes on Roads Adjoining the Central Coast Highway

Existing traffic volume data for roads adjoining the Central Coast Highway was provided from a

2006 study conducted by Northern Transport Planning and Engineering Pty Ltd (NTPE).

These traffic volumes are considered representative of the existing situation, as traffic volumes

along this section of the Central Coast Highway have not increased significantly since 2006.

Heavy vehicle percents range from 1% up to 9%.

Table 3.3 – Traffic volumes on roads adjoining the Central Coast Highway – 2006

Road Period Northbound Volume Southbound Volume

Day: 7am – 10pm 1,075 728 Matcham Rd

Night: 10pm – 7am 111 79

Day: 7am – 10pm 1,263 1,642 Willoughby Rd

Night: 10pm – 7am 180 166

Day: 7am – 10pm 749 636 Old Gosford Rd

Night: 10pm – 7am 82 130

The traffic data presented in Sections 3.2.1 and 3.2.2 were used in model verification (see

Section 3.3.2 below).

3.2.3 Future Traffic Volumes along the Central Coast Highway

Future traffic volume data for the Central Coast Highway was provided by Parsons Brinckerhoff

and is summarised in Table 3.4 and 3.5 below.





2012 volumes are for the “future-existing” scenario (do nothing option at project opening).


Eastbound Westbound


Per Cent Heavy


Day: 7am – 10pm 10,027 4.9 9,977 3.8 Central Coast Highway between Matcham Rd and Willoughby Rd Night: 10pm – 7am 683 6.7 1349 4.7

Day: 7am – 10pm 11,399 4.3 10,868 3.5 Central Coast Highway between Willoughby Rd and Ocean View Dr Night: 10pm – 7am 776 5.8 1,470 4.3


Eastbound Westbound


Per Cent Heavy


Day: 7am – 10pm 12,306 4.9 12,245 3.8 Central Coast Highway between Matcham Rd and Willoughby Rd Night: 10pm – 7am 838 6.6 1,656 4.7

Day: 7am – 10pm 13,989 4.3 13,338 3.5 Central Coast Highway between Willoughby Rd and Ocean View Dr Night: 10pm – 7am 953 5.8 1,804 4.3

3.2.4 Future Traffic Volumes on Roads Adjoining the Central Coast Highway

Future traffic volume data for roads adjoining the Central Coast Highway was provided by

Parsons Brinckerhoff and is summarised in Table 3.6 and 3.7 below. Heavy vehicle percents

range from 1% up to 9%.

2012 volumes are for the “future-existing” scenario (do nothing option at project opening).


Road Period Northbound or

Westbound Volume Southbound or

Eastbound Volume


Night: 10pm – 7am 170 205

Day: 7am – 10pm 845 1,044 Old Gosford Rd

Night: 10pm – 7am 85 106

Day: 7am – 10pm 118 95 O’Kanagan Close

Night: 10pm – 7am 12 10

Day: 7am – 10pm 7,674 8,400 Ocean View Drive

Night: 10pm – 7am 776 850






Road Period Northbound or

Westbound Volume Southbound or

Eastbound Volume


Night: 10pm – 7am 186 227

Day: 7am – 10pm 926 1,144 Old Gosford Rd

Night: 10pm – 7am 94 116

Day: 7am – 10pm 118 100 O’Kanagan Close

Night: 10pm – 7am 12 10

Day: 7am – 10pm 8,436 9,254 Ocean View Drive

Night: 10pm – 7am 854 936

The traffic data presented in Sections 3.2.3 and 3.2.4 were used to model future traffic noise

levels along the Central Coast Highway (see Section 3).

3.3 Noise Prediction Modelling

3.3.1 Noise Prediction Model

The traffic noise prediction model used in this project is based on a method developed by the

United Kingdom Department of Environment entitled “Calculation of Road Traffic Noise (1988)”

known as the CoRTN (1988) method. This method has been adapted to Australian conditions

and extensively tested by the Australian Road Research Board. The model predicts noise levels

for free-flowing traffic and a modified method has been developed which enables an accurate

prediction of noise from high truck exhausts to be taken into account. The method predicts the

L10(1hour) noise levels, and a correction of -3dB(A) is applied to obtain the Leq(1hour) noise levels

for every hour in a 24 hour day.

The Leq(1hour) noise levels for the time period 7.00am to 10.00pm are then collated and

logarithmically averaged to derive the daily Leq(15hour) noise level. Similarly, the Leq(1hour) noise

levels for the time period 10.00pm to 7.00am are collated and logarithmically averaged to

derive the night time Leq(9hour) noise level.

Traffic volumes used in modelling are detailed in Section 3.2.

Distances between vehicles and critical receivers were obtained from site measurements and

from drawings supplied by Parsons Brinckerhoff and the RTA.

The noise prediction model takes into account the following:





Table 3.8 – Summary of Modelling Inputs

Input Parameters Data Acquired From

Traffic volumes and mix Existing: Traffic counts from Austraffic and NTPE

Future: Provided by Parsons Brinckerhoff. Described in more detail in Section 3.2 of the Review of Environmental Factors (REF)

Vehicle speed Central Coast Highway: Posted speed limit of the proposed upgrade will be 60km/h; noise modelling was done for 70km/h as a precautionary measure.

Side Roads: 50km/h

Current speed limits observed during site inspection. Speeds to remain the same through to 2022.

Gradient of roadway From the Proposal as described in Section 3 of the REF

Source height 0.5m for car exhaust, 1.5m for car and truck engines and 3.6m for truck exhaust and detailed within CoRTN88

Ground topography at receiver and road From aerial photos, digital topographic data and the Proposal as described in Section 3 of the REF

Angles of view from receiver Determined during site inspections and aerial photos

Reflections from existing barriers, structures and cuttings on opposite side of road

Determined during site inspections and review of concept design.

Air and ground absorption Detailed within CoRTN88, ground absorption varied along route. Numeric values varied between 0 (hard surface) to 1 (100% absorptive)

Receiver Heights 1.5m above ground level for ground floor and 4.5m above ground level for 1st floor

Facade correction +2.5dB(A)

Acoustic properties of road surfaces Determined during site inspection – dense graded asphalt

Roadside barriers Existing fencing at properties

Prediction model assumes no existing noise walls

Traffic noise levels (LAeq) Based on long term monitoring results

3.3.2 Model Verification

The model was verified and calibrated using the long-term noise monitoring results obtained for

this project.

Table 3.9 summarises the results of the traffic noise model verification, providing a

comparison of the modelled traffic noise levels for existing conditions compared to the

measured traffic noise levels.

Table 3.9 – Noise Model Verification Results

LAeq(15hr) Noise Level LAeq(9hr) Noise Level NCA

Measured Modelled Variation Measured Modelled Variation

1 58 611 +3 52 531 +1

2 52 53 +1 47 46 -1

3 61 63 +2 55 56 +1

4 57 58 +1 52 51 -1





LAeq(15hr) Noise Level LAeq(9hr) Noise Level NCA

Measured Modelled Variation Measured Modelled Variation

5 65 64 -1 60 57 -3

Notes: 1. Includes a -3.6dB correction factor to account for specific characteristics of the M1 measurement location. These characteristics included significant vegetation and partial shielding from the residential building itself.

Variations between measured and modelled noise levels are likely to have occurred due to

differences in actual vehicle numbers, percentages of heavy vehicles, vehicle speeds and

topographic data used in the model compared to actual levels.

The noise model verification tests presented in Table 3.9 above, show the model to predict

results that fall within ± 3dB(A) of the true noise levels in practice. The accuracy of the

CoRTN88 noise algorithms is generally expected to predict noise levels that are within 2.7dB(A)

of the true noise levels in practice with an 85% confidence [RTA’s Interim Traffic Noise Policy

(ITNP), Appendix B, Section 3]. Therefore, the results presented above provide a reasonable

level of confidence in the accuracy of the noise model used for predicting future traffic noise

levels for this project.

The variations listed in the table above were used as ‘calibration factors’ applied to the

predicted traffic noise levels on a catchment by catchment basis.

3.4 Road Traffic Noise Assessment

3.4.1 Prediction Locations

Road traffic noise levels were predicted to all residences within each NCA using noise contour

maps. In addition, further noise modelling was completed at each individual residence.

The noise contours were interpolated from a series of calculations to specific points within a

regularly spaced grid, 1.5 m above ground level. It is noted that the noise contours are

estimates of the predicted noise levels, and that contour values may differ slightly from

equivalent calculations at individual residences.

For calculations at individual residences, all residential buildings were assumed to be single

storey, unless the building height was over 4.5 m (determined from building survey data

provided). Residential buildings over 4.5 m in height were assumed to be double storey

dwellings, in line with a conservative assessment.

Predictions were carried out assuming no noise control measures have been incorporated into

the road development other than those measures detailed in Table 3.8.

Review of predicted noise levels at the nominated, nearest affected residential receivers in each

NCA revealed that noise impacts were generally higher during the day. Therefore, the day

period is the determining period for assessment purposes. Traffic noise levels presented in

Figures 2 through 13 are for ground floor level only.





The future-existing noise levels are the predicted traffic noise levels in year 2012 if the road

upgrade was not to be carried out. The future noise level in 2012 is the predicted traffic noise

level in the year the proposed works are complete and the redeveloped road commences

operation, while the year 2022, represents ten years after the commencement of operation.

Date: 09/09/08

Scale: NTS

Ref: TD780-01P02 (rev 0)

Title :

Figure 2 - 2012 Future Existing day contours - 1.5m

Project :

Central Coast Highway Upgrade -

Matcham Road to Ocean View Drive

CAAA Member of the Association of Australian Acoustical Consultants

Consultants in Acoustics, Vibration and Structural Dynamics

RENZO TONIN& A S S O C I A T E S

Email: [email protected] www.renzotonin.com.au

SydneyPh: (02) 8218 0500 Fax: (02) 8218 0501MelbournePh: (03) 9606 0041 Fax: (03) 9606 0042BrisbanePh: (07) 3211 9155 Fax: (07) 3211 9188Gold CoastPh: (07) 5593 5633 Fax: (07) 5593 5635KuwaitPh: +0011 965 653 1520

inspired to achieve

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60

6065

65

55

50

50

55

50

45

Central Coast Highway

Bru

sh

Ro

ad

Matc

ham

Road

Brooks Hill Lane

NOTES

65dBA

60dBA

55dBA

50dBA

45dBA

Date: 09/09/08

Scale: NTS

Ref: TD780-01P03 (rev 0)

Title :

Figure 3 - 2012 Future Existing day contours - 1.5m

Project :

Central Coast Highway Upgrade -

Matcham Road to Ocean View Drive

CAAA Member of the Association of Australian Acoustical Consultants

Consultants in Acoustics, Vibration and Structural Dynamics

RENZO TONIN& A S S O C I A T E S

Email: [email protected] www.renzotonin.com.au

SydneyPh: (02) 8218 0500 Fax: (02) 8218 0501MelbournePh: (03) 9606 0041 Fax: (03) 9606 0042BrisbanePh: (07) 3211 9155 Fax: (07) 3211 9188Gold CoastPh: (07) 5593 5633 Fax: (07) 5593 5635KuwaitPh: +0011 965 653 1520

inspired to achieve

N

50

55

55

60

6065

45

O'K

anagan C

lose

Central Coast Highway

Old Gosford Road

OceanViewDrive

Will

oughby R

oad

Hig

hV

alley

Clo

se

NOTES

65dBA

60dBA

55dBA

50dBA

45dBA

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