Received 21.08.2020 East Derwent Highway Upgrade Development Application
Change the document title using the properties option on the Jacobs RibbonProject NameClient Name Appendix K. Traffic Impact Assessment Received 21.08.2020
East Derwent Highway Upgrade – Golf Links Road to Sugarloaf Road Traffic Impact Assessment
IS262318 | 3 14 August 2020
Department of State Growth
Traffic Impact Assessment Department of State Growth
Received 21.08.2020
East Derwent Highway Upgrade
Project No: IS262318 Document Title: Traffic Impact Assessment Document No.: IS262318 Revision: 2 Document Status: Final Date: 30 July 2020 Client Name: Department of State Growth
Project Manager: Clayton Johnston Author: Jonathan Bryce and Cassandra Min File Name: IS262318-0000-CT-RPT-0001
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Document history and status
Revision Date Description Author Checked Reviewed Approved
1.0 22/04/20 Initial Draft JB & CM MD MD SF
2.0 30/07/20 Final Version for Client Review JB & CM MD MD SF
3.0 14/08/20 Final Version JB, CM, HG MD MD CJ & NG
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Contents 1. Introduction...... 4 1.1 Background ...... 4 1.2 Purpose of this report ...... 4 1.3 Document Change History ...... 5 1.4 Planning requirements ...... 5 2. Existing Conditions ...... 8 2.1 Site Location ...... 8 2.2 Surrounding Road Network ...... 8 2.3 Modelling Existing and Future Conditions ...... 9 2.4 Traffic Volumes ...... 12 2.5 Signal Data ...... 16 2.6 Base Model ...... 16 2.6.1 Base Model Development ...... 16 2.6.2 Base Model Calibration and Validation ...... 18 2.6.3 Results ...... 19 2.7 Existing Intersection Operation ...... 19 3. Future Network Model ...... 21 3.1 Proposed Design ...... 21 3.2 Traffic Signal Operation ...... 23 3.3 Model Assumptions ...... 24 3.4 Future Volumes ...... 24 3.5 Network Performance ...... 25 3.5.1 Queue Length Comparison ...... 25 3.5.2 Average Delay, LoS and DoS Comparison ...... 29 3.5.3 Internal Road Network ...... 31 3.6 Lindisfarne North Primary School internal arrangement ...... 33 3.6.1 Internal roundabout ...... 34 3.6.2 Southern Egress ...... 34 4. Further Modelling Considerations ...... 35 4.1 Redistribution of right turns from Sugarloaf Road to East Derwent Highway ...... 35 5. Discussion ...... 36 5.1 Network Performance ...... 36 5.1.1 Geilston Bay Road / Dumbarton Drive Roundabout ...... 36 5.1.2 East Derwent Highway / Derwent Avenue / Golf Links Road intersection ...... 36 5.1.3 Saturday Events ...... 36 5.2 Vehicular and Pedestrian Access ...... 36 5.2.1 Lindisfarne North Primary School Precinct...... 36
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5.2.2 Commercial Precinct ...... 37 5.2.3 Adjustment to accesses, Geilston Creek Road ...... 37 5.2.4 Residential Accesses ...... 37 5.2.5 Pedestrian Access ...... 38 5.2.6 Cycling Facilities ...... 38 5.2.7 Parking ...... 38 5.2.8 Departure lanes ...... 38 5.2.9 Traffic Management ...... 39 5.3 Safe Intersection Sight Distance (SISD) ...... 39 6. Conclusion ...... 42
Appendix A. Data Collection Appendix B. Base Model Development and Validation Appendix C. Movement Diagrams Appendix D. Sight Distance at Accesses and Junctions
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1. Introduction
1.1 Background
The Department of State Growth is improving road capacity and safety along the East Derwent Highway (B32) between Golf Links Road and Sugarloaf Road as part of an overall commitment by the Tasmanian Government.
Key design features of the planned upgrades include: ▪ Duplication of the existing single carriageway to provide four through lanes (two lanes in each direction) ▪ Installation of new traffic signals at the Dumbarton Drive / Clinton Road intersection ▪ A new raised central median and safety barriers to reduce ‘head on’ crash types ▪ Safer access off the highway to Araluen Street, Lindisfarne North Primary School and Geilston Bay Recreation Area ▪ The provision of an off-road shared path and on-road cycling lanes to promote active transport ▪ Increased turning capacity at key intersection including School Access Road, Golf Links Road and Sugarloaf Road
The Department of State Growth has requested Jacobs undertake traffic modelling in SIDRA of East Derwent Highway, to assess the impact of the planned road upgrades and perform sensitivity testing based on projected infrastructure developments in this region.
This report also serves as a Traffic Impact Assessment (TIA) for the road upgrade development and has been prepared in accordance with the Department of State Growth’s Framework for Undertaking Traffic Impact Assessments, detailing the findings of the assessment undertaken for the proposed development. This TIA also demonstrates compliance with Development Standards under the relevant codes of Clarence City Council’s Interim Planning Scheme (2015), the local governing authority for the project area.
1.2 Purpose of this report
This report documents the development of the East Derwent Highway SIDRA model and the associated model results to understand the impacts of the design. It is intended to provide appropriate detail such that both State Growth and Council can be confident the modelling outputs (for base and design scenarios) are sufficiently robust and the resulting impacts, as part of a TIA, are assessed appropriately.
This report is structured as follows: ▪ Chapter 2 provides an overview of the existing conditions including site location, surrounding road network, traffic volumes, base model development and assumptions, and existing intersection operation ▪ Chapter 3 provides an overview of the future network model, including the modelled scenarios, proposed design, traffic signal operation, model assumptions and future volumes ▪ Chapter 4 describes scenarios considered during further model development, including the redistribution of traffic, possible pedestrian safety improvements, and the Lindisfarne North Primary School internal road arrangement ▪ Chapter 5 provides commentary on traffic impacts as a result of the upgrade including selected intersections, traffic management during construction, parking and Saturday events ▪ Chapter 6 concludes the report by summarising the performance of the proposed design and recommendations
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1.3 Document Change History The changes enacted in this report compared to the draft report issued in February 2020 are as follows:
Intersection Signal Phasing and Layout
▪ The signal phasing was amended to remove the ‘bonus left’ turns at the East Derwent Highway / Golf Links Road / Derwent Avenue and the East Derwent Highway / Clinton Road / Dumbarton Drive intersection ▪ Lane designation line markings (i.e. through arrows, turn arrows) at the side street approaches to East Derwent Avenue have been removed Geilston Bay Road / Dumbarton Drive intersection
▪ The previously design roundabout at the Geilston Bay Road / Dumbarton Drive intersection has been converted to a priority controlled four-leg unsignalised intersection. Updated Modelling Results
▪ The SIDRA models have been updated to reflect the changes to the design and signal phasing ▪ The SIDRA results and analysis undertaken in Section 3 of this report have been updated with the latest SIDRA network model results Change in outcomes ▪ The results of the modelled scenarios have not significantly changed
1.4 Planning requirements
This report addresses several planning requirements outlined by the Clarence Interim Planning Scheme 2015. The planning scheme requirements are listed below and the location where they are addressed in this report are shown in Table 1.1.
Table 1.1: Planning scheme requirements
Planning Planning Scheme Acceptable solution TIA Reference Scheme code
E5.0 Road and E5.5.1 Existing Road Accesses and Junctions Meets the acceptable solution A11 as there is no Railway Assets intensification of existing use or anticipated induced
Code demand due to upgrades to East Derwent Highway as specified in Sections 3.3 and 3.4. E5.5.2 Exiting Level Crossings N/A
E5.6.1 Development N/A – East Derwent Highway is a Category 3 road Adjacent to Roads and Railways (based on the Tasmanian State Road Hierarchy)
E5.6.2 Road Accesses and Junctions Meets the acceptable solution A1 and A2 as there are no new accesses or junctions to roads in an area subject to a speed limit of more than 60km/h as specified by Section 3.1. Note an existing intersection with the highway is being relocated and replaced as part of the project, but is not considered additional.
1 Acceptable Solutions (A1, A2, A3 etc) are specified in the Clarence Interim Planning Scheme 2015.
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Planning Planning Scheme Acceptable solution TIA Reference Scheme code
E5.6.3 New Level Crossings N/A
E5.6.4 Sight Distance at Accesses, Junctions Meets the acceptable solution A1 as all accesses and and Level Crossings junctions provide sufficient sight distance between vehicles to enable safe movement of traffic, except the junctions below. Meets the performance criteria P1 for parts f) any measures to improve or maintain sight distance; and g) any written advice received from the road or rail authority, for the junctions of Geilston Bay Road / Dumbarton Drive and East Derwent Highway / Dumbarton Drive / Clinton Road. Refer to Section 5.3 which outlines sight distances achieved at these junctions. E6.0 Parking E6.6.1 Number of Car Parking Spaces Meets the acceptable solution A1 as for ‘utility’ use and Access there is no parking space requirement for this use in Code accordance with Table E6.1. As the development itself is not expected to directly impact the size of the student/teacher population, nor is the existing carpark at the school being altered, acceptable solution A1 is also met for “Education and occasional care” use. Overall, there is a reduction in the available parking space along the highway as a result of the upgrade, however, improvements are expected due to the removal of existing no standing zones. Refer to Section 5.2.7. which outlines the parking infrastructure associated with the development. E6.6.2 Number of Accessible Car Parking Refer response to Clause E6.6.1. Spaces for People with a Disability There is no reduction in the number of carparks or additional trips generated. E6.6.3 Number of Motorcycle Parking Spaces Refer response to Clause E6.6.1. There is no reduction in the number of carparks or additional trips generated. E6.6.4 Number of Bicycle Parking Spaces Refer response to Clause E6.6.1. There is no reduction in the number of carparks or additional trips generated. E6.7.1 Number of Vehicular Accesses The design meets acceptable solution A1, as the number of vehicle access points provided for each road frontage is unchanged from the existing. E6.7.2 Design of Vehicular Accesses Refer response to E6.7.1. As there are no new, additional access points as part of the works, existing access locations and footprints have been retained in their existing format or upgraded as far as reasonably practical within a brownfield site to achieve compliance with the relevant Australian Standards. Acceptable solution A1 is achieved, and detailed further in Section 5.2. E6.7.3 Vehicular Passing Areas Along an N/A Access
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Planning Planning Scheme Acceptable solution TIA Reference Scheme code
E6.7.4 On-Site Turning N/A
E6.7.5 Layout of Parking Areas N/A
E6.7.6 Surface Treatment of Parking Areas N/A
E6.7.7 Lighting of Parking Areas N/A
E6.7.8 Landscaping of Parking Areas N/A
E6.7.9 Design of Motorcycle Parking Areas N/A
E6.7.10 Design of Bicycle Parking Facilities N/A
E6.7.11 Bicycle End of Trip Facilities N/A
E6.7.12 Siting of Car Parking N/A
E6.7.13 Facilities for Commercial Vehicles N/A
E6.7.14 Access to a Road The design meets acceptable solution A1 as all access to the road network is provided appropriately and in accordance with requirements of the road authority – these requirements are specified in the Local Government Association (LGAT) Standard Drawings or Department of State Growth specifications. Notably, works undertaken at existing access points, may depart from these standards in some instances where it is not feasible or reasonably practical to achieve them without compromising road safety design outcomes or impacting adjacent landowners. A number of existing accesses in the project area do not meet required standards. Refer to Section 5.2 which summarises key changes to vehicular and pedestrian access onto new or existing roads, and how these each meet the applicable road authority’s requirements within the project area.
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2. Existing Conditions
2.1 Site Location
The site of the planned upgrade is located along the East Derwent Highway between Golf Links Road and Sugarloaf Road in Geilston Bay, Tasmania. Figure 2.1 shows the location of the proposed works.
Figure 2.1: East Derwent Highway project area
2.2 Surrounding Road Network
East Derwent Highway (route number B32) is an 18km long strategic arterial road in State Growth’s road network, paralleling the eastern banks of Derwent River in Hobart and predominately carries commuter traffic. The route is also approved on State Growth’s B-Double network, and HML gazetted south of Faggs Gully Creek. The highway begins at the Tasman Highway Interchange in Rose Bay, travels north to Bowen Bridge, before leading to the Midland Highway in Bridgewater, passing through residential, commercial and bushland areas.
The purpose of this assessment is to examine the impact of the planned upgrade on the overall performance of the East Derwent Highway between Golf Links Road and Sugarloaf Road in Geilston Bay. Land use within the study area includes a local primary school, residential land, recreational facilities and local shops. The model study area captures all major intersections and movements required to assess the traffic impacts of the proposed design for all road users.
The study area includes the following intersections:
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▪ East Derwent Highway and Sugarloaf Road ▪ Geilston Bay Road and Dumbarton Drive ▪ East Derwent Highway and Geilston Bay Road and Clinton Road ▪ East Derwent Highway and Debomfords Lane and Araluen Street ▪ East Derwent Highway and School Entrance ▪ East Derwent Highway and Golf Links Road and Derwent Avenue The site also includes Lindisfarne North Primary School, which contains a sporting oval, internal road network and internal parking. These key sites and intersections are shown in Figure 2.2.
Figure 2.2: Key intersections and control type
2.3 Modelling Existing and Future Conditions
To assess the performance of the existing and proposed design conditions on East Derwent Highway, traffic models have been developed using SIDRA INTERSECTION software (version 8.0), an intersection-analysis
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software package. SIDRA is an advanced micro-analytical tool used to evaluate signalised and unsignalised intersection designs in terms of capacity, level of service (LoS), degree of saturation (DoS), queue length and a wide range of other performance measures. The software is efficient in modelling different types of vehicles classes such as light vehicles, heavy vehicles, buses, pedestrians and cyclists.
The main objective of the modelling is to assess the impact of the proposed development on the overall performance of the highway and associated road network, in terms of average delays, LoS, DoS and queue length for the intersections. The overall traffic modelling approach is outlined below and shown in Figure 2.3. The key components are:
• Surveyed Traffic and SCATS Data – Surveyed turning movement count data was used to determine the peak hours and prepare the input traffic volumes for weekday AM and PM peaks along with the Saturday models. SCATS data was analysed to obtain traffic signal information such as phasing, phase timings and cycle times.
• Base Model Development, Calibration and Validation – Base year (2019) SIDRA models were built for weekday AM and PM peak hours and Saturday peak hour. The base year network was developed based on Google aerial imagery and surveyed traffic. Signal operations were replicated using SCATS signal data information.
• Model Calibration – The calibration process involved iteratively adjusting model parameters until the model represented the existing conditions of traffic in terms of flows, intersection geometry and signal timings in peak periods.
• Model Validation – Comparing the model outcomes with an independent data source to check that the model can appropriately forecast traffic conditions – in this case, queue lengths which were captured by manual surveys undertaken on the same day as the turning movements counts and were used for model validation.
• Design Testing – Assess the impact of the proposed upgrade on the overall performance of East Derwent Highway corridor.
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Figure 2.3: Methodology adopted for the model development
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2.4 Traffic Volumes
Comprehensive traffic surveys were undertaken to understand the current performance of the study area. Automatic traffic counts (ATCs) were conducted for 7 days between Tuesday 15th October and Monday 21st October 2019. Intersection turning movement counts (TMCs) and queue length surveys were carried out on Wednesday 16th October 2019 between 07:00 and 09:00 for the AM peak period and between 15:00 and 18:00 for the PM peak period, and on Saturday 19th October 2019 between 10:00 and 15:00 for the weekend peak period. Table 2.1 shows the summary of the traffic data used for base year SIDRA model development and calibration / validation.
Table 2.1: Surveyed data summary
Data Type Source Survey Date Survey Time
Tuesday 15th October 2019 Automatic traffic Matrix Traffic and 24 hours for 7 days counts (ATC) Transport Data Monday 21st October 2019
07:00 to 09:00 & Wednesday 16th October 2019 Turning movement Matrix Traffic and 15:00 to 18:00 counts (TMC) Transport Data Saturday 19th October 2019 10:00 to 15:00
07:00 to 09:00 & Wednesday 16th October 2019 Queue length Matrix Traffic and 15:00 to 18:00 surveys Transport Data Saturday 19th October 2019 10:00 to 15:00
07:00 to 09:00 & Wednesday 16th October 2019 Journey time Matrix Traffic and 5:00 to 18:00 surveys Transport Data Saturday 19th October 2019 10:00 to 15:00
Data collection locations for the ATCs, TMCs, and queue length surveys can be found in Appendix A.
For the ATCs, tubes deployed at survey locations were used to record vehicle classifications (12-categories) and speeds for 1-hour intervals in both the northbound and southbound direction. To conduct the TMCs, video cameras installed at the survey locations were used to record vehicle movements and traffic throughput in 15- minute intervals. For the queue length surveys, the maximum queue in terms of the number of vehicles queued was recorded for every cycle for East Derwent Highway / Golf Links Road / Derwent Avenue intersection and for every one-minute interval for East Derwent Highway / Sugarloaf Road intersection.
The surveyed data informed the volumes used for base year SIDRA model development and calibration / validation. The volumes and heavy vehicle percentages inputted into the base model are shown in Figure 2.4 to Figure 2.6 below.
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Sugarloaf Road Clinton Road Araluen Street Golf Links Road
21% 4% 25% 4 0% 0% 6% 0% 0% 20% 25 1% 27% 1%
27% 15 19 211 5% 1146 4 1 68 0% 8 9 12 5% 1228 5% 1153 4% 1109 61 11 209
5% 942 0% 3 5% 1220 0% 4 3% 79 10% 20
108 6% 37 3% 4 0% 908 5% 904 5% 54 7% East Derwent Highway
793 4% 17 1 14 875 5% 909 5% 5 4 21 19% 25 1 105 1% 48 10 150 900 4%
0% 0% 0% 6 0% 0% 0% 0% 0% 8% 10% 4% 17 0%
0%
0% 0% 48
0% 23 6 4 0% 76
Dumbarton Drive 0% 1 School Access Road
1 11 132
0% 0% Debomfords Lane 1%
Geilston Bay Road Derwent Avenue
Figure 2.4: Base Model AM Movement Diagram
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Sugarloaf Road Clinton Road Araluen Street Golf Links Road
30% 1% 50% 2 0% 0% 6% 0% 7% 2% 54 3% 5% 2%
9% 22 13 132 2% 897 1 1 49 8% 13 1 15 2% 939 2% 914 2% 817 67 19 96
2% 779 0% 12 2% 942 0% 18 0% 37 2% 44
212 1% 100 2% 12 0% 1304 3% 1283 3% 225 3% East Derwent Highway
973 4% 7 1 9 1177 3% 1304 3% 12 12 26 4% 47 1 61 2% 52 51 83 1225 4%
14% 0% 0% 28 0% 17% 0% 2% 0% 0% 6% 0% 53 0%
1%
0% 0% 102
0% 11 30 11 0% 32 Dumbarton Drive 0% 1 School Access Road
1 6 90
0% 0% Debomfords Lane 1%
Geilston Bay Road Derwent Avenue
Figure 2.5: Base Model PM Movement Diagram
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Sugarloaf Road Clinton Road Araluen Street Golf Links Road
13% 1% 0% 4 0% 0% 3% 0% 0% 4% 23 0% 9% 1%
30% 10 16 142 1% 640 4 2 66 0% 4 11 8 1% 727 1% 732 1% 677 26 11 142
1% 506 0% 4 1% 721 0% 2 0% 1 3% 33
139 0% 73 3% 9 0% 791 1% 779 1% 163 0% East Derwent Highway
576 1% 8 1 19 703 1% 787 1% 5 6 9 0% 10 1 4 0% 43 16 36 725 2%
0% 0% 0% 22 0% 0% 0% 0% 0% 0% 6% 0% 41 0%
1%
0% 0% 86
0% 14 24 4 0% 5
Dumbarton Drive 0% 2 School access road
1 14 90
0% 0% Debomfords Lane 1%
Geilston Bay Road Derwent Avenue
Figure 2.6: Base Model Saturday Movement Diagram
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2.5 Signal Data
The traffic signal operation data included:
▪ SCATS graphics sheets for East Derwent Highway / Golf Links Road / Derwent Avenue Road intersection (#9187), including the detector map and phasing diagram ▪ The SCATS history files for signal controller #9187, detailing the cycle time and phase splits that operated on the same day as the manual traffic surveys
2.6 Base Model
2.6.1 Base Model Development
SIDRA models have been built to provide a representation of traffic conditions for the year 2019, which is defined as the base year and provides a reliable reference point for testing the proposed design.
Figure 2.7 and Figure 2.8 display the data collected by the ATCs. From these figures, the following peak hours were identified for the weekday AM and PM peak hours and the Saturday peak hour. ▪ AM peak: 08:00 to 09:00 ▪ PM peak: 16:30 to 17:30 ▪ Saturday Peak: 11:30 to 12:30
Figure 2.7: Average weekday traffic flow on East Derwent Highway recorded from ATCs
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Figure 2.8: Average Saturday traffic flow on East Derwent Highway recorded from ATCs
The road network was developed based on the Google aerial imagery in SIDRA. The model includes the existing (2019) layout for the East Derwent Highway and adjoining roads (see Appendix B, Figure B.1). TMCs were used to derive the traffic demand for the SIDRA model for weekday AM and PM peak hours and weekend Saturday peak hour. Traffic demand in SIDRA models was coded for light vehicles and heavy vehicles separately.
Signal phasing for East the Derwent Highway / Golf Links Road / Derwent Avenue intersection (#9187) was extracted from SCATS data provided by State Growth for Wednesday 16th October 2019 and Saturday 19th October 2019 and included the detector diagram, phasing diagram and signal timings summary for 15-minute intervals.
The 15-minute interval SCATS data was summarised to extract the average hourly phase timings and phase frequencies for all the three peaks. Figure 2.9 displays the adopted phasing for the East Derwent Highway / Golf Links Road / Derwent Avenue signalised intersection. The intersection operates with 3-phases (A-C-B) with an average cycle length of 105 seconds for the AM peak, 95 seconds for the PM peak and 75 seconds for the Saturday peak.
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Figure 2.9: East Derwent Highway / Golf Links Road / Derwent Avenue – existing phase sequence
Assumptions made during the base model development include: ▪ The signal controller for the East Derwent Highway / Golf Links Road / Derwent Avenue intersection was run using Fixed-Time / Pretimed’ module of SIDRA, for all the three peaks model ▪ The signal controller was operated using ‘User Given Cycle Time’ ▪ Flow discrepancies between adjacent intersections were adjusted manually ▪ Yellow and All-Red times were calculated as per Austroads guidelines ▪ Bus performance was captured as part of the HV performance of the site ▪ All other modelling parameters were kept as default
2.6.2 Base Model Calibration and Validation
Calibration is the process of adjusting model network parameters such that the model accurately reflects observed site conditions. In this case, the SIDRA models for weekday AM and PM peaks and the weekend Saturday peak were calibrated in terms of flows, network geometry and signal timings.
Validation is the process of comparing model outputs against independently measured data that was not used during the calibration process. In this case, the base model has been validated against the surveyed queue lengths, which were recorded for the East Derwent Highway / Golf Links Road / Derwent Avenue intersection and East Derwent Highway / Sugarloaf Road intersection. For model validation purpose, 95th percentile back of queue length were used.
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2.6.3 Results
The three peaks modelled (AM, PM and Saturday) show a good match to the observed queues. The results show that the base models demonstrate a satisfactory ‘goodness of fit’ with the observed on-site traffic conditions and were well-calibrated in terms of volume flows, network geometry and signal timings. Similarly, modelled queue length for all the three peak models were found to be similar to the observed queue lengths as part of the validation process. The base models, therefore, provide a robust representation of the base year conditions within the study area and can be used to assess the performance of the design model.
Refer to Appendix B for the base model validation results.
2.7 Existing Intersection Operation
A SIDRA INTERSECTION network model was developed to assess the existing performance of traffic in the study region. Intersection operational performance was evaluated by assessing the average vehicle delay and its corresponding level of service and the Degree of Saturation (DoS). Intersection LoS was assessed using the methods in accordance with the Austroads Guide to Traffic Management – Part 3 as outlined in Table 2.2 below. For this assessment, intersections operating with an average delay corresponding to a threshold of LoS D are performing adequately. DoS ratings are defined in Table 2.3 below. Intersections operating with a DoS rating of 0.9 or below are deemed adequate in this assessment. Table 2.4 shows the existing layout operating conditions for the base model:
Table 2.2: SIDRA INTERSECTION Level of Service Criteria
Average Delay per Vehicle (sec/veh) Level of Service (LoS) Give-Way/Priority Traffic Signals A d ≤ 10 d ≤ 10 B 10 < d ≤ 15 10 < d ≤ 20 C 15 < d ≤ 25 20< d ≤ 35 D 25 < d ≤ 35 35 < d ≤ 55 E 35 < d ≤ 50 55 < d ≤ 80 F 50 > d 80 > d
Table 2.3: Degree of Saturation Ratings (SIDRA)
Rating Degree of Saturation (DoS) Excellent DoS ≤ 0.6 Very Good 0.6 < x ≤ 0.7 Good 0.7 < x ≤ 0.8 Acceptable 0.8 < x ≤ 0.9 Poor 0.9 < x ≤ 1.0 Very Poor x > 1.0
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Table 2.4: Existing Layout Operating Conditions – 2019 Volumes Average Delays Level of Peak Intersection DoS (Seconds) Service (LoS) East Derwent Highway/Derwent Avenue/Golf Links Road 0.72 26 C AM East Derwent Highway/ Clinton Road/ Geilston Bay > 2.00 19 C East Derwent Highway/Sugarloaf Road 0.29 2 A East Derwent Highway/Derwent Avenue/Golf Links Road 0.87 26 C PM East Derwent Highway/ Clinton Road/ Geilston Bay 1.75 9 A East Derwent Highway/Sugarloaf Road 0.40 2 A East Derwent Highway/Derwent Avenue/Golf Links Road 0.55 21 C Saturday East Derwent Highway/ Clinton Road/ Geilston Bay 0.48 3 A East Derwent Highway/Sugarloaf Road 0.18 2 A
The results above indicate the current network operates sufficiently, with the LoS of each of the intersections (signalised and unsignalised) classified as LoS C or better for all peak periods. Most intersections operate with an adequate DoS of 0.9 or lower. The exception for this is the East Derwent Highway/Clinton Road/Geilston Bay intersection during the AM and PM peak. This is predominantly due to high DoS observed for the right turn lane and through lane at the western intersection approach on Geilston Bay Road.
It should be noted that the results are for the overall intersection performance, with the delay and LoS figures representing average values for the intersection, as opposed to individual approaches.
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3. Future Network Model
The proposed design was tested to better understand the impacts of the future year (2037) projected traffic on the overall performance of the East Derwent Highway and adjacent roads. Four scenarios were modelled: ▪ 2019 Base model – The current road network with current flows ▪ 2019 – The proposed road network with current flows ▪ 2037 – The proposed road network with future flows ▪ 2037 Sensitivity - The proposed road network with future flows and additional trips generated from additional subdivision development and expansion of the school.
3.1 Proposed Design
The proposed design presented in Figure 3.1 includes the following major changes compared to the base scenario: ▪ Duplication of the East Derwent Highway corridor between Golf Links Road and Sugarloaf Road to a four-lane divided carriageway, with two lanes in both the northbound and southbound directions and a new raised centre median. ▪ Upgrades to the East Derwent Highway / Golf Links Road / Derwent Avenue intersection to suit the wider highway footprint. The right-turning lane storage length for the north approach has been increased from 50m to 90m; the right-turning lane storage length for the south approach has been reduced from 65m to 60m. U- turns have been allowed at the north approach. ▪ Upgrades to the East Derwent Highway / School Entrance intersection has altered the school access point just north of Golf Links Road to be left in only from East Derwent Highway (south). This has been provided through a dedicated left-turn lane with approximately 50m storage length, separated from highway through traffic. ▪ The East Derwent Highway / Clinton Road / Geilston Bay Road will be reconfigured and repositioned to 50m south of the existing intersection and be upgraded with traffic signals. The existing connection of Geilston Bay Road to the highway will be converted to a cul-de-sac, and Dumbarton Drive extended over Faggs Gully Creek to the western approach of the new signalised intersection. The current T intersection of Geilston Bay Road and Dumbarton Drive will be upgraded to four-leg unsignalised intersection to accommodate the Dumbarton Drive extension over the creek. Improvements at the new signalised intersection also involves increasing the right turning lane storage length for the south approach from 60m to 80m and a new right turning lane with storage length of 45m is provided for the north approach. A U-turn is also provided at the south approach. ▪ The existing East Derwent Highway / Debomfords Lane intersection will be closed. A new local road will connect from the extension of Dumbarton Drive to the current Debomfords Lane alignment and provide a new access point to Lindisfarne North Primary School. ▪ Construction of a new internal roundabout at the northern side of Lindisfarne North Primary School will provide a link to the new school access road from Dumbarton Drive. ▪ East Derwent Highway / Araluen Street intersection has been converted to a ‘left in left out’ intersection. ▪ Storage capacity for the right turn lane at the southern approach to the East Derwent Highway / Sugarloaf Road intersection has been increased from 55m to 135m. ▪ 1.5m wide bicycle lanes have been implemented along East Derwent Highway with head-start boxes at intersections. ▪ Pedestrian access improvements including a new 2.5m wide shared user path along the western side of the highway connecting the school and recreational areas. A pedestrian fence will also be installed in the new central median between Golf Links Road and Clinton Road to deter haphazard pedestrian crossings.
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Figure 3.1: Proposed design layout for East Derwent Highway
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3.2 Traffic Signal Operation
In the proposed design, signal operations for the East Derwent Highway / Golf Links Road / Derwent Avenue intersection have been optimised to ensure improved performance. With updated phases, the intersection runs using a 5-phase cycle, the phase sequence A-B/C-D-E1/E2 and an optimised cycle time, as shown in Figure 3.2. Phases B, C, E1 and E2 are repeat phases and their operation is demand dependent.
Similarly, the upgraded East Derwent Highway / Clinton Road / Dumbarton Drive signalised intersection will run using a 5-phase cycle, as shown in Figure 3.3, with phase sequence A-B/C-D-E1/E2 where phases B, C, E1 and E2 are repeat phases and their operation is demand dependent.
Figure 3.2: East Derwent Highway / Golf Links Road / Derwent Avenue – phasing sequence
Figure 3.3: East Derwent Highway / Clinton Road / Dumbarton Drive – phasing sequence
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3.3 Model Assumptions Assumptions made during the design model development are as follows: ▪ East Derwent Highway / Clinton Road / Dumbarton Drive operates at the same cycle time as East Derwent Highway / Golf Links Road / Derwent Avenue intersection for improved coordination of movements. ▪ With the conversion of Araluen Street to a ‘left in left out’ configuration, all the right turning vehicles from Araluen Street have been added to the left-turning vehicles and re-routed via a U-turn at the East Derwent Highway / Golf Links Road / Derwent Avenue intersection. Similarly, all right-turning vehicles from East Derwent Highway into Araluen Street are re-routed via a U-turn at East Derwent Highway / Clinton Road / Dumbarton Drive intersection. ▪ With the permanent closure of the East Derwent Highway / Debomfords Lane intersection, all vehicles have been re-routed through the East Derwent Highway / Clinton Road / Dumbarton Drive and Dumbarton Drive / Debomfords lane intersections. ▪ With the upgrade of the East Derwent Highway / School Entrance intersection, all right-turning vehicles from East Derwent Highway (north) to the school have been re-routed through the East Derwent Highway/ Clinton Road/ Dumbarton Drive intersection, which is designed to provide access to the Lindisfarne North Primary School. Similarly, vehicles which previously turned left from the school exit onto East Derwent Highway have been re-routed to the north through the new school access road to access East Derwent Highway via the East Derwent Highway / Clinton Road / Dumbarton Drive intersection. Vehicles which previously turned right from the school access onto East Derwent Highway have been re-routed south onto Derwent Avenue, to provide access to the southbound lanes on East Derwent Highway. ▪ Based on the previous traffic studies conducted for the East Derwent region, a growth rate of 1.32% per annum was applied to the existing (2019) traffic flows to obtain the 2037 future traffic flows2. ▪ Since East Derwent Highway is the only major north-south road east of the River Derwent which provides a connection to Hobart, there is minimal route choice available to drivers. As a result, upgrades to East Derwent Highway are not expected to induce additional traffic demand and influence the growth rate.
3.4 Future Volumes
The 2037 sensitivity model includes volumes generated from the 130 dwellings proposed to be constructed as part of a sub-division in the north-west region of the study area. Trips were generated in-line with the ITE trip generation rates for the AM, PM and Saturday peak periods and distributed onto the network in accordance with current trip patterns. It has been assumed 80% of vehicles accessing and departing the new dwellings will utilise the East Derwent Highway/ Clinton Road/ Dumbarton Drive intersection, the remaining 20% will utilise the East Derwent Highway / Piper road intersection further to the north.
The 2037 sensitivity model includes additional trips generated due to the proposed expansion (doubling the number of students) of the Lindisfarne North Primary School. Trips were generated in-line with the ITE trip generation rates for the AM, PM and Saturday peak periods and distributed onto the network in accordance with current trip patterns.
Trip generation and distribution can be seen in Table 3.1. The associated movement diagrams can be found in Appendix C.
2 In absence of any information available for future pedestrians, the East Derwent Highway / Golf Links Road / Derwent Avenue signalised intersection is run using same pedestrian numbers as in the base models, 50 pedestrians per hour (default for SIDRA).
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Table 3.1: Trips generated due to developments
Total Generated Trips Total Distribution of Generated Trips Development AM Hour PM Hour Weekend Weekend Daily AM In AM Out PM In PM Out 8-9am 4:30-5:30pm In out Additional trips due to school 961 335 112 184 151 55 57 - - expansion Additional trips due to 130 1,238 98 130 24 73 82 48 62 62 dwellings
As shown above, the total generated trips from future development differ on the hour. Since AM Peak hour coincides with school start times, a significant number of additional trips are generated due to school expansion. In contrast, the PM Peak hour does not coincide with school end times, thus there are fewer additional trips generated due to school expansion when compared to the AM peak.
3.5 Network Performance
Queue length, average delay, LoS and DoS parameters were used to assess the network performance of the base model and design model. Queue length, delay, LoS and DoS can reasonably reflect the traffic operational conditions. Overall, the purpose of the modelling exercise was to ensure the design was sufficiently catering for future demand.
3.5.1 Queue Length Comparison
Consideration of 95th percentile queues helps to ensure the majority of queues do not exceed their storage capacity. Table 3.2 to Table 3.4 show the 95th percentile queue length (m) for the base case model and proposed design in the AM, PM and Saturday peaks.
Additionally, these tables display the storage capacity of each lane. When the 95th percentile queue exceeds the designed lane length, the cell is highlighted in red.
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Table 3.2: Base vs preferred option design queue length comparison - AM peak
95th Percentile Queue Length (meters) Design Lane Junction Name Approach Name Movement Length (m) 2037 2019 Base 2019 Design 2037 Design Sensitivity Left 40 <10 <10 <10 <10 Through 13 370 67 105 185 269 East Derwent Highway (South) Through 2 370 181 105 163 245 East Derwent Right 60 23 18 30 30 Highway/ Left 50 69 53 83 78 Golf Links Road (East) Derwent Right + Through 400 23 18 28 27 Avenue/Golf Left + Through 430 164 145 294 420 Links Road East Derwent Highway (North) Through 430 158 146 287 413 Right 90 <10 <10 10 10 Left + Through 65 18 14 20 30 Derwent Avenue (West) Right 260 57 47 81 140 Left + Through 430 - 87 146 164 East Derwent Highway (South) Through 430 - 87 140 151 Right 80 - 11 18 22 East Derwent Left 200 - 19 34 33 Clinton Road (East) Highway/ Right + Through 20 - <10 <10 <10 Clinton Road/ Left + Through 915 - 122 149 165 Dumbarton Drive East Derwent Highway (North) Through 915 - 106 123 117 Right 45 - 25 28 50 Left + Through 40 - 13 23 46 Dumbarton Drive (West) Right 40 - <10 <10 24 East Derwent Highway (South) Right 130 <10 10 21 25 East Derwent Left 25 <10 <10 <10 <10 Highway/ Sugarloaf Road (East) Right 250 <10 19 139 164 Sugarloaf Road East Derwent Highway (North) Left 180 <10 <10 <10 <10
3 Lanes are ordered from the left-hand side, heading north
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Table 3.3: Base vs proposed design queue length comparison - PM peak
95th Percentile Queue Length (meters) Design Lane Junction Name Approach Name Movement Length (m) 2019 Base 2019 Design 2037 Design 2037 Sensitivity Left 40 <10 <10 <10 <10 Through 14 370 77 155 281 353 East Derwent Highway (South) Through 2 370 241 112 186 237 Right 60 71 44 82 91 East Derwent Left 50 33 26 46 48 Highway/ Derwent Golf Links Road (East) Right + Through 400 31 24 44 47 Avenue/Golf Links Left + Through 430 115 118 205 225 Road East Derwent Highway (North) Through 430 107 119 196 213 Right 90 16 13 23 25 Left + Through 65 35 18 33 44 Derwent Avenue (West) Right 260 29 35 64 83 Left + Through 430 - 96 178 222 East Derwent Highway (South) Through 430 - 97 145 179 Right 80 - 22 38 40 East Derwent Left 200 - 17 30 30 Clinton Road (East) Highway/ Clinton Right + Through 20 - <10 <10 <10 Road/ Dumbarton Left + Through 915 - 86 157 182 Drive East Derwent Highway (North) Through 915 - 86 132 144 Right 45 - 20 34 51 Left + Through 40 - 19 33 47 Dumbarton Drive (West) Right 40 - <10 10 30 East Derwent Highway (South) Right 130 14 19 57 76 East Derwent Left 25 <10 <10 <10 <10 Highway/Sugarloaf Sugarloaf Road (East) Right 250 <10 29 56 62 Road East Derwent Highway (North) Left 180 <10 <10 <10 <10
Table 3.4: Base vs proposed design queue length comparison - Saturday peak
4 Lanes are ordered from the left-hand side
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95th Percentile Queue Length (meters Design Lane Junction Name Approach Name Lane No. Length (m) 2037 2019 Base 2019 Design 2037 Design Sensitivity Left 40 <10 <10 <10 <10 Through 15 370 35 76 105 109 East Derwent Highway (South) Through 2 370 96 76 105 109 Right 60 41 40 53 56 East Derwent Left 50 38 35 43 43 Highway/Derwent Golf Links Road (East) Right + Through 400 <10 10 12 12 Avenue/Golf Links Left + Through 430 72 71 96 98 Road East Derwent Highway (North) Through 430 73 72 96 99 Right 90 <10 <10 <10 <10 Left + Through 65 11 10 13 13 Derwent Avenue (West) Right 260 14 13 16 16 Left + Through 430 - 75 78 83 East Derwent Highway (South) Through 430 - 75 78 83 Right 80 - 19 23 23 East Derwent Left 200 - 18 21 21 Clinton Road (East) Highway/ Clinton Right + Through 20 - <10 <10 <10 Road/ Dumbarton Left + Through 915 - 43 67 67 Drive East Derwent Highway (North) Through 915 - 43 67 67 Right 45 - <10 <10 <10 Left + Through 40 - <10 <10 10 Dumbarton Drive (West) Right 40 - <10 <10 17 East Derwent Highway (South) Right 130 <10 <10 12 12 East Derwent Left 25 <10 <10 <10 <10 Highway/Sugarloaf Sugarloaf Road (East) Right 250 <10 <10 <10 <10 Road East Derwent Highway (North) Left 180 <10 <10 <10 <10
5 Lanes are ordered from the left-hand side
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A summary of key findings from the queue length comparison is listed as follows: ▪ 2019 Base Model
- AM peak displays queues exceeding storage capacity at the eastern approach to the East Derwent Highway / Derwent Avenue / Golf Links Road intersection for the short left and through lane.
- PM peak displays queues exceeding storage capacity at the southern approach to the East Derwent Highway / Derwent Avenue / Golf Links Road intersection for right turns.
- No lanes exceed storage capacity for Saturday peak periods ▪ 2019 Design Model
- Network shows generally improved performance when compared to the 2019 Base Model.
- AM peak displays queues exceeding storage capacity at the eastern approach to the East Derwent Highway / Derwent Avenue / Golf Links Road intersection for the short left and through lane
- No lanes exceed storage capacity for PM and Saturday peak periods. ▪ 2037 Design Model
- Queues are generally longer than the 2019 Design Model, which is expected given increased volumes
- AM peak displays queues exceeding the queue storage capacity at the eastern approach to the East Derwent Highway / Derwent Avenue / Golf Links Road intersection for the short left and through lane
- PM peak displays queues exceeding storage capacity at the southern approach to the East Derwent Highway / Derwent Avenue / Golf Links Road intersection for right turns.
- No lanes exceed storage capacity for Saturday peak periods. ▪ 2037 Sensitivity Model
- Network experiences increased queues which begin to exceed their storage capacity, due to increased trips generated by school expansion and development of dwellings
- AM peak displays queues exceeding the queue storage capacity at the eastern approach to the East Derwent Highway / Derwent Avenue / Golf Links Road intersection for the short left and through lane, and the northern approach to the East Derwent Highway / Clinton Road / Dumbarton Drive intersection for right turns, as well as the western approach to the East Derwent Highway / Clinton Road / Dumbarton Drive intersection for the left and through turn lane.
- PM peak displays queues exceeding storage capacity at the southern approach to the East Derwent Highway / Derwent Avenue / Golf Links Road intersection for right turns. At the northern approach to the East Derwent Highway / Clinton Road / Dumbarton Drive intersection for right turns, as well as the western approach to the East Derwent Highway / Clinton Road / Dumbarton Drive intersection for the left and through turn lane.
- No lanes exceed storage capacity for Saturday peak periods.
For all scenarios, PM queues on the right lane of the south approach of the East Derwent Highway/Derwent Avenue/Golf Links Road intersection exceed storage capacity. Consideration should be given to increasing the storage capacity of the right turn lane at the southern approach to the intersection.
3.5.2 Average Delay, LoS and DoS Comparison
Table 3.5 shows the intersection delays, LoS and DoS for the base model and the proposed design for the AM, PM and Saturday peak periods.
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Table 3.5: Intersections delay, LoS and DoS comparison for base vs proposed design
Average Delays (Seconds) Level of Service (LoS) Degrees of Saturation (DoS)
Peak Intersection 2037 2037 2037 2019 2019 2037 2019 2019 2037 2019 2019 2037 Sensitivity Sensitivity Sensitivity Base Design Design Base Design Base Design Design Model Design Model Model East Derwent Highway/Derwent 26 24 34 57 C C C E 0.72 0.74 0.89 0.99 Avenue/Golf Links Road East Derwent Highway/ AM Clinton Road/ 19 18 18 21 C B B C >2.00 0.62 0.60 0.67 Dumbarton Drive East Derwent 2 4 20 26 A A C D 0.29 0.76 >2.00 >2.00 Highway/Sugarloaf Road East Derwent Highway/Derwent 26 23 30 33 C C C C 0.87 0.73 0.83 0.87 Avenue/Golf Links Road East Derwent Highway/ PM Clinton Road/ 9 16 19 23 A B B C 1.75 0.52 0.64 0.68 Dumbarton Drive East Derwent 2 5 10 12 A A A B 0.40 1.00 1.76 1.92 Highway/Sugarloaf Road East Derwent Highway/Derwent 21 23 24 24 C C C C 0.55 0.55 0.70 0.71 Avenue/Golf Links Road East Derwent Highway/ Saturday Clinton Road/ 3 17 16 16 A B B C 0.48 0.55 0.50 0.52 Dumbarton Drive East Derwent 2 2 3 3 A A A A 0.18 0.25 0.38 0.39 Highway/Sugarloaf Road
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The East Derwent Highway / Derwent Avenue / Golf Links Road intersection performs with reduced delays during the AM, PM and Saturday peak periods when comparing the 2019 base model to the 2019 design model. Due to the projected traffic growth, both the 2037 Design and 2037 sensitivity models operate with increased delays. During the most congested period, the 2037 AM sensitivity model, the intersection operates with a LoS E and a DoS < 1.
Upgrading the East Derwent Highway / Clinton Road / Dumbarton Drive intersection from an unsignalised intersection to a signalised intersection will result in a safer intersection configuration, and provide greater consistency in traffic flow. During the AM peak period, the operation of the intersection will improve from a LoS C to a LoS B, and a reduction in DoS is seen when comparing the 2019 base and 2019 design model. Despite the increase in volumes from both traffic growth and trips generated from the school expansion and housing development, the intersection will still operate at a LoS B in the AM period for the 2037 models. The intersections performance during both the PM and Saturday peak will decrease in DoS, however, it will experience an increase in delays. During the worst case 2037 sensitivity model, the intersection will perform at a LoS C.
SIDRA modelling displays an increase in delays and DoS at the East Derwent Highway / Sugarloaf Road intersection for both the AM and PM models in 2037. These increases in delays and DoS are due to increased waiting time for vehicles turning right into and out of Sugarloaf Road. Right turning vehicles are low in volume, thus it is anticipated that if delays are excessive, vehicles will redistribute to the East Derwent Highway / Clinton Road / Dumbarton Drive intersection to perform their right turn movement at the signalised intersection.
All intersections in the proposed design will perform at an adequate LoS, with most of the intersections performing at a LoS C or better in the AM, PM and Saturday models. Generally, the 2019 design model experiences smaller delays than the base model. The 2037 sensitivity model experiences an increase in delays at most intersections which can be attributed to the increase in traffic flows. Only the East Derwent Highway / Derwent Avenue / Golf Links Road intersection in the 2037 sensitivity model performs with an LoS E or worse, The delay for this intersection is only two seconds greater than the threshold for a LoS D and it is likely advanced signal timing modifications and signal co-ordination would ensure adequate performance in the future. All other intersections performed satisfactorily.
3.5.3 Internal Road Network
The SIDRA network also included the local roads adjacent to East Derwent Highway. These roads and their intersections performed satisfactorily during each of the peak periods. During the most congested modelled scenario, the 2037 AM sensitivity model, the internal networks and intersections perform at a LoS A. This can be seen in Figure 3.4.
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Figure 3.4: 2037 PM Sensitivity LoS
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3.6 Lindisfarne North Primary School internal arrangement
The proposed alignment of the school internal road network has three connections to the wider road network ▪ Access-only from the east, which provides access to vehicles travelling northbound on East Derwent Highway ▪ Access from the north through the proposed school access road which connects to Dumbarton Drive, providing access to the school for vehicles travelling north and south on East Derwent Highway ▪ An egress-only point in the south providing access to Derwent Avenue
Figure 3.5: Road connections from school to the wider network
To assess the performance of the school road network, the 2037 sensitivity model has been analysed as this is seen as the worst-case scenario due to additional trips generated from the school expansion. Furthermore, a 15- minute peak flow period has been applied to replicate real-world conditions and the intensity of school drop off and pick up periods.
Vehicles departing the school seeking to travel southbound on East Derwent Highway are expected to exit the school via the southern egress point onto Derwent Avenue and to turn right onto East Derwent Highway at the East Derwent Highway / Derwent Avenue / Golfs Link Road intersection. Vehicles departing the school seeking to travel northbound on East Derwent Highway are expected to exit the school via the new school access road and Dumbarton Drive, north of the school, before turning left onto East Derwent Highway at the East Derwent Highway / Dumbarton Drive / Clinton Road intersection.
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3.6.1 Internal roundabout
The performance of the internal school roundabout is satisfactory. During the worst-case scenario, every approach operates at a LoS A with average delays under 10 seconds. Queues from the east approach are 12m and will not extend back to East Derwent Highway.
3.6.2 Southern Egress
During the AM peak period, the southern egress point onto Derwent Avenue is expected to cater for a higher proportion of departing school traffic due to the higher demand for southbound movements on East Derwent Highway. Furthermore, due to the concurrent peaks between general traffic and school drop off, the AM peak period is the most congested period for the school region.
Vehicles exiting at the southern egress of the school and turning right from Derwent Avenue onto East Derwent Highway are required to access the right turning lane on Derwent Avenue which will require vehicles to change lanes. Vehicles have 30m to perform this action due to the proximity between the existing school exit and the East Derwent Highway/ Derwent Avenue / Golfs Link Road intersection.
Based on the SIDRA 2037 sensitivity model, an excess of 180 vehicles are expected to perform lane changes in the AM peak. Queues greater than 30m are expected on the west approach to the East Derwent Highway/ Derwent Avenue / Golfs Link Road intersection. Given the queue and the large number of lane changes required, there is likely to be a blockage of the left and through lane on Derwent Avenue. Furthermore, long queues will prevent vehicles from exiting the school at the southern exit resulting in queues developing and extending back into the school. Despite the complexity of traffic operations in this area, SIDRA modelling exhibits minimal queues at the school exit turning left onto Derwent Avenue with the average delay under 10 seconds. However, it is noted that traffic performance in this region is complex and SIDRA network modelling is not the ideal tool for analysing the arrangement. If more detailed analysis and a greater understanding of traffic performance is required, microsimulation modelling is recommended.
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4. Further Modelling Considerations
4.1 Redistribution of right turns from Sugarloaf Road to East Derwent Highway
The East Derwent Highway / Clinton Road / Dumbarton Drive intersection should be promoted as a route choice to reduce the use of the Sugarloaf Road / East Derwent Highway intersection. Two main benefits of this are to reduce delays and improve safety.
Modelling has been undertaken to test the impacts of redistribution traffic turning right from Sugarloaf Road into East Derwent Highway to the East Derwent Highway/ Clinton Road/ Dumbarton Drive intersection. TMCs indicate that less than 10% of traffic exiting Sugarloaf Road perform right turn movements onto East Derwent Highway. The volume of right-turning vehicles is small, with under 20 vehicles performing this action each peak period. Modelling was undertaken on the most congested scenario, the 2037 AM sensitivity, the results can be seen in Table 4.1 and Table 4.2
Table 4.1: Average delays and LoS - Redistribution of right turns from Sugarloaf Road
Average Delays (Seconds) Level of Service (LoS)
Peak Intersection 2037 2037 Sensitivity 2037 2037 Sensitivity Sensitivity Model Sensitivity Model Model (Redistribution) Model (Redistribution) East Derwent Highway/ Clinton 21 22 C C Road/ Dumbarton Drive AM East Derwent Highway/Sugarloaf 26 <5 D A Road
Table 4.2: 95th Percentile queue lengths - Redistribution of right turns from Sugarloaf Road
Average Delays (Seconds) 2037 2037 Sensitivity Design Lane Peak Approach Lane No. Sensitivity Model Length (m) Model (Redistribution) AM Peak AM Peak
East Derwent Highway/ East Left + Through 200 21 34 Clinton Road/ Dumbarton Drive East Through + Right 20 9 20
Redistribution of traffic from the East Derwent Highway / Sugarloaf Road to the East Derwent Highway / Clinton Road / Dumbarton Drive intersection does not negatively impact the average delays at any intersection in the network in the AM. As a result of the redistribution of traffic to the east approach of the East Derwent Highway / Clinton Road / Dumbarton Drive intersection, the through and right lane experiences an increase in queues. However, these increases are marginal and the largest queue occurring is 20m long. Overall, redistributing traffic from Sugarloaf Road results in negligible impact to the traffic network. This is expected as volumes performing this action are very small with less than 20 vehicles in both the AM and PM peaks.
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5. Discussion
5.1 Network Performance
The proposed development in the study area has changed the performance of selected areas within the network. A list of network performance assessments has been outlined below:
5.1.1 Geilston Bay Road / Dumbarton Drive Roundabout
The Geilston Bay Road / Dumbarton Drive intersection has been upgraded from a T-intersection to a four-leg unsignalised intersection. Performance of the intersection is satisfactory with all approaches operating at LoS A.
A sensitivity test was conducted on the roundabout to reflect the school zone traffic behaviour, adjusting the peak hour factor to 15 minutes on SIDRA. Performance on the roundabout remains unchanged, with all approaches operating at a LoS A.
5.1.2 East Derwent Highway / Derwent Avenue / Golf Links Road intersection
During the PM peak period, queues at the southern approach to the East Derwent Highway / Derwent Avenue /Golfs Link Road intersection exceed the storage capacity for the right turn in the 2037 design and 2037 sensitivity scenario. Consideration should be given to increasing the storage capacity of the right turn lane at the southern approach to the East Derwent Highway / Derwent Avenue /Golfs Link Road Intersection.
5.1.3 Saturday Events
Anecdotes from key project stakeholders helped provide details of congestion in the region during public events held on weekends at the sporting precinct adjacent to Debomfords Lane within the study area. Typical events include sporting matches and school athletics activities. No major community events were held at the time of the traffic counts; thus no event data was captured to supplement the Saturday peak modelling.
Community consultation indicated seasonal sporting events attract approximately 50 vehicles to the area, whereas, one-off yearly events such as the school cross country attract much greater numbers. Given the improved access and egress points connecting to Debomfords Lane, as well as lower volumes on Saturday than AM and PM peaks, traffic congestion on the network is not anticipated based on the recreational precinct’s current usage. This will be true particularly if the school cross country event is relocated from the area, which has been noted by the Lindisfarne North Primary School principal. Furthermore, it is expected the proposed works will result in enhanced traffic performance and safety during future events.
5.2 Vehicular and Pedestrian Access
Based on the Clarence Interim Planning Scheme 2015, access to a road applies to both vehicles and pedestrians entering or leaving a road, from land adjoining a road. A summary of key changes to vehicular and pedestrian access to new or existing roads, and how these each meet the applicable road authority’s requirements within the project area, is provided below: 5.2.1 Lindisfarne North Primary School Precinct
There have been a number of improvements for ingress and egress to Lindisfarne North Primary School, with the intent of easing congestion and improving safety: ▪ The exit onto Derwent Avenue will remain ‘left out only,’ with minor improvements including installation of a small triangular concrete island to discourage prohibited left in movements and a central concrete
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median on Derwent Avenue to prevent prohibited right turn movements. In addition, no stopping line marking will be painted west of the access along Derwent Avenue to ensure sightlines to eastbound vehicles are kept clear. The existing arrangement is retained due to brownfield site constraints; there are no works occurring on Derwent Avenue west of the access and therefore sight distance is equivalent to existing conditions. Safety of the access is considered to have improved as right turn movements are prevented by the physical median. ▪ The current access to the school, approximately 150m north of the Golf Links Road intersection, allows all left and right ingress and egress movements. This arrangement often contributes to congestion during peak periods internally within the school, and also causes vehicles turning into the access to queue back along the highway and affect through traffic flow. There have been a number of accidents and near misses associated with this access as a result. ▪ Access to and from the school off East Derwent Highway has undergone significant rationalisation to ease congestion and improve safety. The existing access point has been retained in its current location but rationalised to a ‘left in only’ dedicated turn lane, thereby preventing left-outs, and all right-turn movements. This turn lane into the school will allow vehicles to decelerate and queue without impacting the flow on the adjacent through lanes. The dedicated left-turn lane meets minimum length and geometric requirements, designated by the road authority’s guidelines (Department of State Growth) and has been verified through traffic modelling. All other existing movements into the school area will be reinstated through the provision of a new signalised intersection at Dumbarton Drive / Clinton Road and dedicated school access road separate from the highway. This school access road meets minimum width requirements specified in LGAT Standard Drawings for a local through road.
5.2.2 Commercial Precinct
Discussions about access arrangements for retail businesses accessed from the highway and Nubeena Crescent have been ongoing with the affected business owners as part of the Preliminary Design. The intent is to retain the current access point off the highway into this commercial area and minimise impacts. The access off the highway does not currently meet LGAT standards, with respect to driveway profile requirements, however in order to minimise impacts to the commercial area and given the brownfield nature of the site, no other improvements are proposed in this location, with the exception of a new crossover. There is also a current ingress and egress point from Nubeena Crescent to this precinct.
5.2.3 Adjustment to accesses, Geilston Creek Road
Geilston Creek Road provides access to a number of residential dwellings east of East Derwent Highway. Based on stakeholder feedback received from selected residents near the new intersection of Clinton Road with the highway, an access road will be provided for residents at 328 and 330 East Derwent Highway to Geilston Creek Road. This new access road will meet the width requirements of an equivalent short local road cul-de-sac, with the geometry to be compliant with Austroads guidelines. This arrangement will provide greater separation between the residents’ egress points and the adjacent traffic signals and also provide greater flexibility and safety in ingress and egress from their properties when using some of their larger vehicles.
5.2.4 Residential Accesses
Due to pavement and footpath improvements proposed along the eastern side of the highway between Golf Links Road and Clinton Road, minor works to existing driveway crossovers will be required. Any crossover impacted will be reinstated in its existing position and meet the minimum width requirements for urban driveways under the LGAT Standards. Due to the formalised parking and bicycle lanes, the highway through lanes are further from these accesses and therefore sight lines are less acute than existing conditions.
There are some accesses and associated footpath grades which do not currently meet LGAT Standards with respect to vertical transitions and/or crossfall. In some instances, it is acknowledged that is not feasible to
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improve these existing deficiencies to meet the required standards without adversely impacting adjacent properties or compromising the safety of the road design. As far as reasonably practical, improvements have been made where possible.
5.2.5 Pedestrian Access
There will be improved pedestrian access and safety features within the project area, particularly around the school and in vicinity to Clinton Road. Haphazard pedestrian crossings will be deterred through provision of a central median fence along the highway and on Derwent Avenue, and pedestrians will have infrastructure directing them safely to a controlled crossing location. The existing footpath along the eastern side of the highway will be reinstated and improved, in accordance with LGAT Standards. A new shared user path for pedestrians and cyclists will be provided along the western side of the highway between the existing pedestrian crossings at Derwent Avenue / East Derwent Highway and a new signalised pedestrian crossing at East Derwent Highway / Clinton Road. This new crossing point will replace the existing uncontrolled pedestrian refuge island across the highway near Araluen Street. All other new crossing points across minor roads (e.g. in the recreation area and near the school) have been designed in accordance with Austroads guidelines and LGAT Standards.
5.2.6 Cycling Facilities
Formalised on-highway bicycle lanes are provided in both northbound and southbound directions. Bicycle lanes are 1.5 m wide except where adjacent to the parking lane, on the eastern side of the highway between Golf Links Road and Clinton Road, where the width is increased to 2.0 m to mitigate the risk of door strikes. Bicycle lanes are to be painted green at conflict zones such as intersections and bus stops to alert drivers to the presence of cyclists.
The shared user path also provides a lower speed avenue of travel for cyclists away from the highway, with Wombat pedestrian crossings across Debomfords Lane and the left-turn exit lane from the highway to the school roundabout.
5.2.7 Parking
Given the predominant use type of the highway and local roads is classed as “Utilities,” in accordance with Table E6.1 of the Planning Scheme, car parking spaces and measures are not required for the Utilities use class. As such, many of the Development Standards related to parking within E6.0 Parking and Access Code are not applicable. A dedicated parking lane is to be provided along the eastern side of the East Derwent Highway from Clinton Road to Golf Links Road, with a combined length of available parking equal to approximately 115m. This will replace the existing, informal on-street parking in the same location, which approximately equates to a total combined length of 200m. As such, there is a reduction in the amount of available on-street parking in this area. Notably, sections of the existing parking area operate as a no standing zone during peak hours, however, these existing no standing zones will not be reinstated as part of the upgrade.
The other use applicable within the project area is “Education and occasional care”, however as there are no changes to the internal car parking arrangement within the Lindisfarne North Primary School car park, nor is the development directly expected to influence the teacher and student population or induce additional demand to this area, acceptable solution A1 is achieved in this case.
5.2.8 Departure lanes
The design does not include line markings on the side street approaches to East Derwent Highway at Derwent Avenue, Golfs Link Road, Clinton Road and Dumbarton Drive, as directed by State Growth and in line with the existing layout of the Golf Links Road / Derwent Avenue signals. Each of these approaches has two lanes and legally allows for a full range of movements in accordance with AS1742.2, Figure 5.8. The absence of line
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markings and single departure lanes at intersections will lead to a dependence on driver compliance to ensure safety. Consideration should be given to formalise the lane disciplines on both the approach and departure side.
5.2.9 Traffic Management
Construction activities will need to be carefully managed during construction to ensure that delays and disruption are minimised, recognising the importance of reliable journey times to the local school. A Traffic Management Plan will be a requirement of the construction contractor.
5.3 Safe Intersection Sight Distance (SISD)
Standard E5.6.4 of the Scheme requires an access or junction to comply with the SISD shown in Table E5.1 to achieve the Acceptable Solution. For speed limits of 50km/h, 70km/h and 110km/h, SISD of 80m, 140m and 290m are required, respectively.
All accesses and the following junctions achieve the Acceptable Solution A1:
- East Derwent Highway / Golf Links Road / Derwent Avenue
- East Derwent Highway / Araluen Street
- East Derwent Highway / Sugarloaf Road
- Dumbarton Drive / Debomfords Lane
- Debomfords Lane / School Access Road SISD is not achieved and there does not comply with A1 for the East Derwent Highway / Clinton Road / Dumbarton Drive and Dumbarton Drive / Geilston Bay Road junctions. The Performance Criteria P1 of Standard E5.6.4 states that the design, layout and location of a junction must provide adequate sight distances to ensure the safe movement of vehicles, having regard to (f) any measures to improve or maintain sight distance and (g) any written advice received from the road or rail authority, amongst others. SISD is not achieved at these two junctions in accordance with Table E5.1 of the Scheme due to key design decisions made at the direction of State Growth and the Council regarding the location of these accesses and connecting roads, to allow for future development by minimising impacts on private residences, recreational facilities and the school. A cut batter limited by an Aboriginal heritage site is impeding sight lines from Dumbarton Drive when viewing the highway; the acute angles between the highway and Clinton Road and between Dumbarton Drive and the eastern approach of Geilston Bay Road limit sight distance through a maximum 110o sighting angle in accordance with Austroads Guide to Road Design Part 4A: Unsignalised and Signalised Intersections. Advisory speed signage is provided on approach to the Dumbarton Drive / Geilston Bay Road intersection, which requires less sight distance by alerting drivers and advising them to slow. The East Derwent Highway / Clinton Road / Dumbarton Drive intersection is signalised, and therefore SISD is provided as a mitigating factor in the event signals are not working or a vehicle chooses to disobey the signals. In this situation, drivers are expected to be more alert and reduce speed on approach. SISD is considered to comply with the Performance Criteria P1 at these two junctions for these reasons. The available SISD at these junctions is shown in Table 5.1; the suffix OTL refers to the inside lane of the highway in either direction. Insufficient sight distances are highlighted red. SISD for the remaining junctions is shown in Appendix D along with the sight distance criteria under the Scheme.
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Table 5.1: Safe Intersection Sight Distance Failures
SISD Checks for Cars – Object Height 1.25m, Driver Eye Height 1.10m
Criterion Approach 1 1 OTL 2 2 OTL 3 3 OTL 4 4 OTL
Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual
East Derwent Highway / Clinton Road / Dumbarton Drive Intersection
Dumbarton Drive 95 140 78 (84) 140 140 498 140 498 140 373 140 498 80 122 (104)
Clinton Road 140 315 140 340 140 503 140 503 140 189 140 499 80 138
EDH Southbound 80 123 80 120 80 30 80 34 80 121 140 499 140 500 Approach
EDH Northbound 80 133 80 132 80 119 80 119 80 90 140 498 140 498 Approach
Dumbarton Drive / Geilston Bay Road Intersection
Geilston Bay Road – 80 80 80 33 80 220 80 195 Eastern Approach
Geilston Bay Road – 80 227 80 84 80 80 80 81 Western approach
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6. Conclusion
This study has provided a traffic impact assessment for proposed capacity and safety improvements along East Derwent Highway (B32) between Golf Links Road and Sugarloaf Road. The performance of improvements has been assessed in relation to congestion, efficiency and safety. The planned upgrades include duplication of the existing single carriageway to provide four through lanes (two lanes in each direction) and intersection improvements, including installation of new traffic signals at the Dumbarton Drive / Clinton Road intersection.
Traffic modelling in SIDRA was undertaken to assess the impact of the road upgrades and perform sensitivity testing based on project infrastructure developments in the region.
The analysis and discussion presented in this report can be summarised as follows: ▪ The proposed design (2019) generally shows an improved performance when compared to the existing scenario layout (Base Model 2019), with a reduction in the number of lanes exceeding their storage capacity for the AM, PM and Saturday peak periods. ▪ All intersections perform with an adequate LoS and are expected to operate at a satisfactory level of service until at least 2037, with the exclusion of the AM 2037 sensitivity analysis which had a single intersection operate at LoS E. ▪ For all modelling scenarios, PM queues on the right lane of the southern approach of the East Derwent Highway / Derwent Avenue / Golf Links Road intersection exceed storage capacity. Consideration should be given to increasing the storage capacity of the right turn lane at the southern approach to this intersection. ▪ The local roads and their intersections adjacent to East Derwent Highway perform adequately for all peak periods. During the most congested scenario (2037 AM Sensitivity Model), local networks perform at a LoS A. ▪ The performance of the internal roundabout at Lindisfarne North Primary School is satisfactory. During the worst-case scenario, every approach operates at a LoS A with average delays under 10 seconds. ▪ Due to long queues and the large number of lane changes on Derwent Avenue approaching the East Derwent Highway / Derwent Avenue / Golfs Link Road intersection, there is likely to be a blockage on the left and through lane of Derwent Avenue in the AM peak. These long queues may prevent vehicles from exiting the southern egress at Lindisfarne North Primary School, resulting in queues developing and extending back into the school. ▪ The option of redistributing traffic from Sugarloaf Road results in negligible impact to the traffic network. This is expected as volumes performing the right turn movement from the intersection are very small with less than 20 vehicles in both the AM and PM peaks. ▪ Potential solutions to aid pedestrian safety include split phasing, late start, reduced speeds, signage and supervised crossings. ▪ Performance of the upgraded Geilston Bay Road / Dumbarton Drive roundabout is satisfactory with all approaches operating at a LoS A. ▪ Given the improved access and egress points connecting to Debomfords Lane, as well as lower volumes on Saturday than AM and PM peaks, traffic congestion on the network for Saturday events is not anticipated. Furthermore, it is expected the proposed works will result in enhanced traffic performance and safety during future events. ▪ There are a number of vehicular and pedestrian access improvements within the Lindisfarne North Primary School precinct, the commercial precinct and on residential driveways along selected areas of Geilston Creek Road and East Derwent Highway.
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▪ There is no car parking required for the development. ▪ Construction activities will need to be carefully managed during construction to ensure that delays and disruption are minimised, recognising the importance of reliable journey times to the local school.
Overall, duplication of East Derwent Highway results in a safer, more consistent road network with a greater capacity. With 18 years of traffic growth and increased trips generated from the development of 130 additional dwellings and expansion of the Lindisfarne North Primary School, intersections within the project area still operate at a satisfactory LoS with queues mostly contained within their storage capacity. These results are reflected in the AM, PM and Saturday Peak period.
In addition, the proposed upgrade has been assessed under the requirements of schedules E5.0 (Road and Rail Asset Code) and E6.0 (Parking and Access Code) of the Clarence Interim Planning Scheme 2015 and has been assessed to meet the requirements of the Scheme. The proposal meets most of the Scheme’s applicable Acceptable Solutions and relies on Performance Criteria for sight distance for only two junctions under Standard E5.6.4.
Therefore, it is concluded that the proposed road design network shows overall improvement after duplication of East Derwent Highway.
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Appendix A. Data Collection
ATC 3 East Derwent Highway (270m North of Geilston Bay Road)
ATC 2 East Derwent Highway (Between Debomfords Lane and Araluen Street)
ATC 1 East Derwent Highway (Between Nubeena Street and Broad Street)
Figure A.1: Automated traffic count (ATC) locations
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East Derwent Hwy & Sugarloaf Rd
1 0
Geilston Bay Rd & Dumbarton East Derwent Hwy & Geilston Dr Bay Rd & Clinton Rd
1 1 0 0
East Derwent Hwy & 1 East Derwent Hwy & School Debomfords Ln & Araluen St 0 entrance 1 0 East Derwent Hwy & Golf Links 1 Rd & Derwent Ave 0
Figure A.2: Turning movement count (TMC) locations
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1 0 East Derwent Hwy & Sugarloaf Rd
East Derwent Hwy & Golf Links Rd & Derwent Ave
1 0 Figure A.3: Queue length measurement locations
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Appendix B. Base Model Development and Validation
Figure B.1: SIDRA network layout for East Derwent Highway
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Table B.1: 95th percentile back of queue length validation results – AM peak Intersection Name Approach Name Lane Configuration 95% Observed Queue 95% Modelled Queue Left turn 0 1 Through 63 67 East Derwent Highway (South) Through 126 181 Right Turn 28 23 Left turn 63 69 East Derwent Highway/Derwent Golf Link Road (East) Through and Right 35 23 Avenue/Golf Links Road Left turn and Through 140 164 East Derwent Highway (North) Through 126 158 Right Turn 21 8 Left turn and Through 21 18 Derwent Avenue (West) Right Turn 63 57 East Derwent Highway (South) Right Turn 7 8 East Derwent Highway/Sugarloaf Left turn 7 9 Sugarloaf Road (East) Road Right Turn 21 5 East Derwent Highway (North) Left turn 0 0
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Figure B.2: 95th percentile back of queue length validation results – AM peak
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Table B.2: 95th percentile back of queue length validation results – PM peak Intersection Name Approach Name Lane Configuration 95% Observed Queue 95% Modelled Queue Left turn 0 2 Through 84 77 East Derwent Highway (South) Through 189 241 Right Turn 70 71 Left turn 35 33 East Derwent Highway/Derwent Golf Link Road (East) Through and Right 35 31 Avenue/Golf Links Road Left turn and Through 119 115 East Derwent Highway (North) Through 84 107 Right Turn 21 16 Left turn and Through 35 35 Derwent Avenue (West) Right Turn 49 29 East Derwent Highway (South) Right Turn 14 14 East Derwent Highway/Sugarloaf Left turn 7 4 Sugarloaf Road (East) Road Right Turn 14 3 East Derwent Highway (North) Left turn 0 1
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Figure B.3: 95th percentile back of queue length validation results – PM peak
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Table B.3: 95th percentile back of queue length validation results – Saturday peak Intersection Name Approach Name Lane Configuration 95% Observed Queue 95% Modelled Queue Left turn 0 1 Through 42 35 East Derwent Highway (South) Through 105 96 Right Turn 56 41 Left turn 35 38 East Derwent Highway/Derwent Golf Link Road (East) Through and Right 14 9 Avenue/Golf Links Road Left turn and Through 84 72 East Derwent Highway (North) Through 84 73 Right Turn 21 9 Left turn and Through 21 11 Derwent Avenue (West) Right Turn 28 14 East Derwent Highway (South) Right Turn 14 5 East Derwent Highway/Sugarloaf Left turn 0 4 Sugarloaf Road (East) Road Right Turn 7 1 East Derwent Highway (North) Left turn 0 0
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Figure B.4: 95th percentile back of queue length validation results – Saturday peak
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Appendix C. Movement Diagrams
Golf Links Road Sugarloaf Road Clinton Road Araluen Street
20% 25
21% 4% 25% 4 0% 0% 6% 0% 4% 1119 2% 27% 0%
27% 15 19 211 5% 1073 4 1 69 0% 8 12 10% 15 64 11 209
5% 940 0% 83 5% 1152 5% 1164 0% 5
103 6% 5 0% 924 5% 924 5% 58 7% East Derwent Highway
814 5% 50 1 18 33 3% 113 0% 48 10 150 925 4%
0% 0% 0% 872 5% 8% 10% 4% 17 0%
14 0%
0% 0% 0% 0% 0% 0%
10 89 0% 79 0% 1 7 105 1 48
0% 11 0% 79 0% 76
37 0% 28 0% School access road
32 1 1 0% 9 1 8 0% 28 77 132
0% 0% 0% 0% 0% 0% 1%
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
0% 22 1 1 1
Geilston Bay Road 0% 1
1 0%
1 1 10 6 0%
0% 0% 0% 4 0%
Dumbarton Drive
Figure C.1: 2019 Design - AM Movement Diagram
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Golf Links Road Sugarloaf Road Clinton Road Araluen Street
2% 54
30% 1% 50% 2 0% 0% 6% 7% 2% 830 3% 5% 2%
9% 22 13 132 2% 853 1 1 53 8% 13 15 2% 39 68 19 96
2% 790 0% 67 2% 914 2% 929 0% 5
205 1% 5 0% 1300 3% 1301 3% 235 3% East Derwent Highway 1018 3% 63 1 19 104 2% 71 1% 52 51 83 1252 4%
2% 0% 0% 1157 3% 0% 6% 0% 53 0%
38 0%
0% 0% 0% 0% 0% 0%
40 66 0% 37 0% 1 13 58 1 115
0% 31 0% 37 0% 32
64 0% 46 0% School access road
17 1 1 0% 18 1 13 0% 46 30 154
0% 0% 0% 0% 0% 0% 1%
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
0% 11 1 1 1
Geilston Bay Road 0% 1
1 0%
1 1 6 29 0%
0% 0% 0% 10 0%
Dumbarton Drive
Figure C.2: 2019 Design - PM Movement Diagram
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Sugarloaf Road Clinton Road Araluen Street Golf Links Road
<- 4% 23
13% 1% 0% 15 0% 0% 3% 0% 1% 686 0% 9% 1%
30% 10 16 142 1% 647 3 2 66 0% 4 7 3% 28 30 11 142
1% 526 0% 6 1% 735 1% 742 0% 5
139 0% 5 0% 809 1% 809 1% 171 0% East Derwent Highway
586 1% 11 3 26 66 3% 9 0% 44 16 36 744 2%
0% 0% 0% 711 1% 0% 6% 0% 41 0%
27 0%
0% 0% 0% 0% 0% 0%
28 7 0% 1 0% 1 5 4 1 85
0% 7 0% 1 0% 1
12 0% 1 0%
28 1 1 0% 11 1 5 0% 1 1 95
0% 0% 0% 0% 0% 0% 0%
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
0% 14 1 1 1 Geilston Bay Road 0% 1
1 0%
1 1 14 24 0%
0% 0% 0% 4 0%
Dumbarton Drive
Figure C.3: 2019 Design - Saturday Movement Diagram
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Golf Links Road Sugarloaf Clinton Road Araluen Street
20% 30
21% 4% 20% 5 0% 0% 6% 0% 4% 1414 1% 29% 0%
26% 19 24 266 5% 1355 5 1 87 0% 9 12 11% 19 82 14 264
5% 1198 0% 105 5% 1455 5% 1468 0% 5 East Derwent Highway 129 5% 5 0% 1167 5% 1167 5% 73 7%
1039 5% 63 1 23 43 3% 143 0% 58 12 188 1170 4%
0% 0% 0% 1101 5% 9% 8% 3% 21 0%
17 0%
0% 0% 0% 0% 0% 0%
12 111 0% 79 0% 1 9 133 1 58
0% 11 0% 100 0% 76
47 0% 28 0%
40 1 1 0% 9 1 8 0% 35 75 183
0% 0% 0% 0% 0% 0% 1%
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
0% 27 1 1 1
Geilston Bay Road 0% 1
1 0%
1 1 12 7 0%
0% 0% 0% 5 0%
Dumbarton Drive
Figure C.4: 2037 Design - AM Movement Diagram
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Golf Links Road Sugarloaf Clinton Road Araluen Street
1% 68
8% 1% 50% 2 0% 0% 6% 5% 2% 1049 2% 4% 2%
7% 27 12 167 2% 1077 1 1 67 6% 16 19 2% 50 85 24 120
2% 995 0% 85 2% 1154 2% 1172 0% 5 East Derwent Highway 259 1% 5 0% 1643 3% 1643 3% 287 3%
1286 3% 79 1 24 126 2% 90 1% 66 64 105 1517 3%
1% 0% 0% 1462 3% 0% 5% 0% 67 0%
48 0%
0% 0% 0% 0% 0% 0%
51 84 0% 47 0% 1 17 73 1 115
0% 39 0% 47 0% 32
81 0% 58 0%
22 1 1 0% 23 1 16 0% 58 1 203
0% 0% 0% 0% 0% 0% 1%
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
0% 14 1 1 1 Geilston Bay Road 0% 1
1 0%
1 1 8 37 0%
0% 0% 0% 13 0%
Dumbarton Drive
Figure C.5: 2037 Design - PM Movement Diagram
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Sugarloaf Clinton Road Araluen Street Golf Links Road
3% 29
10% 1% 0% 19 0% 0% 2% 0% 1% 865 0% 7% 1%
30% 13 20 179 1% 816 4 2 82 0% 5 9 3% 36 38 14 170
1% 663 0% 7 1% 926 1% 935 0% 5 East Derwent Highway 176 0% 5 0% 1022 1% 1022 1% 216 0%
739 1% 14 3 33 82 4% 12 0% 55 20 45 916 2%
0% 0% 0% 897 1% 0% 5% 0% 52 0%
35 0%
0% 0% 0% 0% 0% 0%
35 9 0% 1 0% 1 6 5 1 85
0% 9 0% 1 0% 1
15 0% 1 0%
35 1 1 0% 14 1 6 0% 1 1 95
0% 0% 0% 0% 0% 0% 0%
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
0% 18 1 1 1
Geilston Bay Road 0% 1
1 0%
1 1 18 30 0%
0% 0% 0% 5 0%
Dumbarton Drive
Figure C.6: 2037 Design - Saturday Movement Diagram
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Golf Links Road Sugarloaf Clinton Road Araluen Street
+19 20% 30
21% 4% 20% 5 0% 0% 6% 0% +26 4% 1440 1% 29% 0%
26% 19 24 266 5% 1355 5 20 87 0% 9 12 11% 19 82 14 264
+86 4% 1284 +86 0% 191 +26 5% 1481 +26 5% 1494 0% 5
129 5% 5 0% 1180 5% +13 1180 5% +13 73 7% East Derwent Highway
1094 4% +55 125 10 49 51 3% +8 248 0% +105 58 54 269 1288 4% +118
0% 0% 0% 1101 5% 9% 2% 2% 21 0%
+62 +9 +26 30 0% +13 +42 +81
+19 +79 +105 +1
0% 0% 0% 0% 0% 0%
31 190 +100 0% 179 0% 1 9 238 1 59
+3 0% 14 +79 0% 179 +122 0% 198
76 0% +29 64 0% +36
105 1 1 0% 11 1 10 0% +2 64 198 183
0% 0% 0% 0% 0% 0% 1%
+65 +2 +29 +123
Debomfords Lane
Road to School Parking +9 Derwent Avenue
0% 1 0% 0% 0%
+57 0% 84 1 1 10
Geilston Bay Road 0% 1 1 0%
1 1 12 26 0% +19
0% 0% 0% 5 0%
Dumbarton Drive
Figure C.7: 2037 Sensitivity Design - AM Movement Diagram
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Golf Links Road Sugarloaf Road Clinton Road Araluen Street
+9 1% 68
8% 1% +9 9% 11 0% 0% 6% 5% +24 2% 1073 2% 4% 2%
7% 27 12 167 2% 1077 1 10 67 6% 16 19 2% 50 85 24 120
+43 2% 1038 +32 0% 117 +24 2% 1178 +24 2% 1196 0% 5 East Derwent Highway 259 1% 5 0% 1690 3% +47 1690 3% +47 296 3% +9
1310 3% +24 106 10 51 126 2% 130 1% +40 66 79 135 1669 3% +152
1% 0% 0% 1462 3% 0% 5% 0% 67 0%
+27 +9 +27 97 0% +49 +15 +30
+56 +15 +40 +31
0% 0% 0% 0% 0% 0%
107 99 +15 0% 62 0% 1 17 113 1 146
0% 39 +15 0% 62 +43 0% 75
95 0% +14 72 0% +14
60 1 1 0% 23 1 16 0% 72 75 204
0% 0% 0% 0% 0% 0% 0%
+38 +14 +74 +1
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
+38 0% 52 1 1 1 Geilston Bay Road 0% 1
1 0%
1 1 8 95 0% +58
0% 0% 0% 13 0%
Dumbarton Drive
Figure C.8: 2037 Sensitivity Design - PM Movement Diagram
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Sugarloaf Road Clinton Road Araluen Street Golf Links Road
3% 29
10% 1% 0% 19 0% 0% 2% 0% +31 1% 896 0% 7% 1%
31% 13 20 179 1% 816 4 2 82 0% 5 9 3% 36 38 14 170
+9 1% 672 0% 7 +31 1% 957 +31 1% 966 0% 5
176 0% 5 0% 1065 1% +43 1065 1% +43 216 0% East Derwent Highway
761 1% +22 37 3 63 85 4% +3 12 0% 55 20 45 959 2% +43
0% 0% 0% 897 1% 0% 5% 0% 52 0%
+23 +30 76 0% +41
+50 +22 0% 0% 0% 0% 0% 0%
85 9 0% 1 0% 1 6 5 1 107
0% 9 0% 1 0% 1
15 0% 1 0%
85 1 1 0% 14 1 6 0% 1 1 119
0% 0% 0% 0% 0% 0% 0%
+50 +24
Debomfords Lane
Road to School Parking Derwent Avenue
0% 1 0% 0% 0%
+62 0% 80 1 1 1
Geilston Bay Road 0% 1
1 0%
1 1 18 80 0% +50
0% 0% 0% 5 0%
Dumbarton Drive
Figure C.9: 2037 Sensitivity Design - Saturday Movement Diagrams
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Appendix D. Sight Distance at Accesses and Junctions
Figure D.1: Sight Distance Criteria 1-4 Under Standard E5.6.4 of the Scheme - Criterion 1 is for Vehicle 1 viewing Vehicle 2.
- Criterion 2 is for Vehicle 1 viewing Vehicle 3.
- Criterion 3 is for Vehicle 3 viewing Vehicle 4.
- Criterion 4 is for Vehicle 4 viewing Vehicle 2.
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Table D.1: Safe Intersection Sight Distance
SISD Checks for Cars – Object Height 1.25m, Driver Eye Height 1.10m Criterion Approach 1 1 OTL 2 2 OTL 3 3 OTL 4 4 OTL
Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual Req’d Actual
East Derwent Highway / Golf Links Road / Derwent Avenue Intersection Golf Links Road 165 140 140 220 140 141 140 179 140 199 140 209 80 129 (165)
Derwent Avenue 140 220 140 216 140 498 140 498 140 498 140 498 80 90
EDH Southbound 80 123 80 119 80 150 80 150 80 80 140 224 140 224 Approach
EDH Northbound 80 150 80 150 80 101 80 107 80 107 140 498 140 498 Approach
East Derwent Highway / Sugarloaf Road Intersection
Sugarloaf Road 290 300 290 300 290 500 290 500 290 500 290 500 290 300 290 300
Dumbarton Drive / Debomfords Lane Intersection
Debomfords Lane 80 80 80 163 80 158 80 80
Debomfords Lane / School Access Road Intersection
School Access Road 80 108 80 97 80 88 80 95
East Derwent Highway / Araluen Street Intersection
Araluen Street 80 499 80 500
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