4.0 Existing Situation - Western Australian Planning ... daps/metro east jdap...t14.026.vb.r01f.docx Page 7 4.0 Existing Situation ... Gordin Way forms a full ... such daily and peak

t14.026.vb.r01f.docx Page 7

4.0 Existing Situation

The subject site is situated within a largely undeveloped area approximately 450m west of the Byford town centre. It is located on the northern side of Abernethy Road immediately northeast of the Abernethy Road/Gordin Way intersection and the Byford Senior High School campus. The subject site accommodates a single residential dwelling at the Abernethy Road frontage with the balance of the site vacant (refer Figure 1). Gordin Way forms a priority-controlled T-intersection with Abernethy Road adjacent to the southwest corner of the site.

4.1 Existing Road Network

Abernethy Road has a Regional Distributor classification between Soldiers Road and South Western Highway but is classified as a Local Distributor west of Soldiers Road in the Main Roads WA Metropolitan Functional Road Hierarchy. West of Soldiers Road it is a single carriageway rural road with a 7.4m sealed width, unsealed shoulders and table drains. In the vicinity of the site a 2.0m concrete path is in place along the southern side of Abernethy Road connecting the school site to the Byford town centre. Abernethy Road has a speed limit of 60km/h between Soldiers Road and Hopkinson Road with a 40km/h school zone in the immediate vicinity of the subject site. The average weekday traffic volume on Abernethy Road in 2010 was 3,550 vehicles per day (vpd) west of Soldiers Road and 5,550vpd at the railway crossing in 2011. Gordin Way is constructed as a single carriageway, two-lane road that includes 1.5m on-road cycle lanes and shared paths adjacent to the school site. This road is classified as an Access Street operating with a default built-up area speed limit of 50km/h. It has a 40km/h school zone speed limit adjacent to the school site. No traffic volume data is available for this road at present. Gordin Way forms a full-movement, priority-controlled T-intersection with Abernethy Road adjacent to the subject site. No crash information is available on the Main Roads WA website for the Abernethy Road/Gordin Way intersection in the five-year period ending in December 2014.

4.2 Public Transport Access

Existing public transport in Byford is limited and of relatively low frequency. Three existing bus routes (No. 251, 253 and 254) service Byford from Armadale and travel on Soldiers Road, about 150m east of the subject site, as shown in Figure 3.


Together these existing bus services provide one bus per hour each way on Soldiers Road on weekdays and less on weekends. There are also existing school bus services in this area with school bus stops located on Abernethy Road west of Soldiers Road and west of Warrington Road. The map of existing public transport services available in the vicinity of the subject site is provided in Figure 3.

Figure 3: Existing bus routes (source: Transperth)


4.3 Pedestrian and Cyclist Facilities

The Perth Bike Map series published by the Department of Transport shows Abernethy Road as a good road riding environment and South Western Highway as a poor road riding environment (see Figure 4). However, there are existing footpaths or shared paths on the roads adjacent to the site:

Abernethy Road has a 2.0m wide shared path on the southern side from Soldiers Road to just west of Thatcher Road. A 1.8m wide traffic island and pram ramps have been installed immediately west of Soldiers Road to assist pedestrians to cross Abernethy Road to the 1.2m wide footpath on the northern side between Soldiers Road and South Western Highway; and,

Soldiers Road has a 1.2m wide footpath on the western side from Abernethy Road to Mead Street. South of Mead Street the footpath widens to 1.8m.

The Department of Transport’s Perth Bike Map series shows good pedestrian and cyclist connectivity to the site.

Figure 4. Bike map (source: Department of Transport)


5.0 Changes to Surrounding Transport Networks

The Byford Structure Plan (shown at Appendix B) makes provision for Byford town site to grow to around 10,000 dwellings. The BTCLSP (see Appendix C) proposes expansion of the Byford Town Centre west of the railway line. Most of the retail and commercial land uses will be north of Abernethy Road but there will be some commercial development along both sides of Abernethy Road east of Gordin Way. The plan also proposes R15, R25, R30 and R60 residential development in neighbouring areas north, west and south of the town centre extension. The BTCLSP and BSP show a future north-south road link (labelled “San Simeon Boulevard” but also referred to as “Thomas Road Deviation”) on the western side of the town centre extension, connecting to Abernethy Road at the Gordin Way intersection and forming a four-way intersection immediately adjacent to the subject site. Both documents contemplated signalised control for this intersection. The GHD January 2014 report examined this intersection and recommended and confirmed traffic signal intersection control. The schematic layout suggested in the report is shown in Figure 5.

Figure 5. Future San Simeon Boulevard/Abernethy Road/Gordin Way intersection

as proposed in the Byford Town Centre Structure Plan (GHD, January 2014)


A new north-south road link (labelled “Main Street”) is proposed to connect the town centre extension with Abernethy Road and form a T-intersection immediately southeast of the subject site. According to the same GHD report this intersection was proposed to be signalised; however, following subsequent consideration and liaison with Main Roads WA by SoSJ, it has been advised that signalisation is no longer proposed for this intersection. Recently, the Shire has engaged Jacobs to prepare detailed design drawing for Abernethy Road upgrade to dual carriageway standard including the relevant intersections with side roads. The design includes signalised intersection for the intersection of Abernethy Road/San Simeon Boulevard/Gordin Way and priority-controlled T-intersection for Abernethy Road and Main Street. At present Jacobs are in the process of finalising this design. Historically, the intersection of Abernethy Road/San Simeon Boulevard/Gordin Way was always identified as signal-controlled in relevant local structure planning documents. However, following the latest extensive three-party discussions between the Shire, Main Roads WA and the proponent, it has been advised that the future intersection of Abernethy Road/San Simeon Boulevard/Gordin Way is no longer planned as a signalised four-way intersection. Instead, this intersection is now proposed to function as a four-way dual-lane roundabout intersection in line with the latest Main Roads WA policy to replace planned future traffic signals with roundabouts wherever applicable and practical. This change in planning, as explained by Main Roads WA, is motivated by anticipated reduction in life-time maintenance costs, crash severity potential and energy consumption. It is also noteworthy that a left-turn lane from Abernethy Road into Main Street is no longer proposed. This situation has presented an opportunity for implementation of a full-movement crossover on Abernethy Road (approximately midway between San Simeon Boulevard and Main Street) to the subject site as shown in the development plan in Appendix A. This full movement crossover will be operating until San Simeon Boulevard and Main Street is constructed and Main Street is transferred to Shire as a public Road. At this time the Abernethy Road crossover is proposed to convert to left in/left out arrangement. In line with the GHD January 2014 report, in the immediate vicinity of the subject site Abernethy Road is proposed to be widened to 35m road reserve width. The future upgrading of Abernethy Road includes a 6m wide median with two through lanes in each direction and one turning lane and with 4m and 7m wide verges. The proposed 35m road reserve does not allow for on-street cycling lanes, widened median or additional turn lanes. Future San Simeon Boulevard and Main Street are proposed as single carriageway, two lane roads with 30m and 25m road reserves, respectively. At present, the site to the east of Main Street is being developed by Coles with two crossovers on Main Street. The proposed southern Coles car park crossover is located almost opposite the subject development’s Main Street crossover and as a result and following consultation with Shire and Main Roads WA a a four-way mini-


roundabout intersection is proposed at this location. The concept design for the Main Street mini-roundabout can be found in Appendix D of this report.


6.0 Integration with Surrounding Area

The proposed development is of a retail/commercial character and as such is in line with planning objectives outlined in the BSP and BTCLSP documents. The site will ultimately have very good road accessibility from two frontages (Abernethy Road and Main Street) coupled with the future access to the pedestrian/cyclist path network. The existing bus routes are only a short walk east of the site on Soldiers Road (about 200m walking distance). According to the BTCLSP document one of the future bus routes proposed to service the structure plan would be passing the site along Main Street providing suitable travel alternatives, particularly for the employees.


7.0 Traffic Assessment

7.1 Assessment Period

The proposed development is of retail and commercial character and as such will generate highest traffic movements during typical Thursday evening even though this weekday peak time has abated with the introduction of late night shopping and seven-day week trade. The traffic assessment for the year 2031 seems appropriate considering most of the roads featuring in the BSP or BTCLSP plan are currently non-existent. The 2031 scenario assumes full development of the BTCLSP area including all proposed land uses and all elements of the proposed road network. It is also assumed that at this stage the proposed development subject of this report will be fully developed and integrated into the BTCLSP. Two assessment scenarios were undertaken reflecting alternative forms of the Abernethy Road crossover, as follows:

Interim scenario: Abernethy Road modelled as a full-movement crossover; and,

Ultimate scenario: Abernethy Road modelled as a restricted left-in/left-out crossover.

7.2 Trip Generation and Distribution

The traffic volume that will be generated by the proposed development has been estimated using trip generation rates derived from the Roads and Traffic Authority of New South Wales Guide to Traffic Generating Developments (2002) and Director-General of Transport South Australia Land Use Traffic Generation Guidelines (1987) which are in line with the assumptions used in the GHD report to forecast the traffic generation of the BTCLSP. Accordingly, it is estimated that in year 2031 the proposed development would generate approximately 3,176 total Thursday trips (both inbound and outbound) with approximately 336 trips (both inbound and outbound) during the Thursday evening peak hour period. The forecast trip generation is based on the assumption that the subject development forms part of the wider commercial zone within the BTCLSP and as such daily and peak hour trip rates for the “supermarket” of 10,000m2 – 20,000m2 GFA were used in this instance. This is also in line with the trip rates used in the GHD report for the retail/commercial type of land use. Due to the anticipated mix of future land uses within the town centre retail/commercial precinct as well as within the proposed development itself, there


will be many incidences of multi-purpose trips1 within the development and between the proposed development and future adjacent land uses (i.e. cross-trade). The cross-trade adjustment for the subject development is however included in the proposed trip generation rate. The directional split of inbound and outbound trips for the proposed development is estimated to be about 50/50 for inbound/outbound trips for all development components during the Thursday evening peak period. The distribution of traffic to and from the proposed development has been derived from the GHD report and is cognisant of the future road network layout, access/egress routes to and from the subject site and the local and regional catchment areas and attractors. Hence, the directional split of traffic to and from the site is assumed as follows:

55% of all traffic to and from Abernethy Road east direction; 15% of all traffic to and from Abernethy Road west direction; 10% of all traffic to and from San Simeon Boulevard north direction; 10% of all traffic to and from Main Street north direction; 10% of all traffic to and from Gordin Way south direction;

7.3 Traffic Flows

The traffic movements generated by the proposed development have been manually assigned on the future road network and the resulting traffic movements generated by this development for the typical Thursday evening peak hour and total daily flows are shown in Figure 6 and Figure 7 for the interim and ultimate access system scenarios, respectively.

1 Multi-purpose trips are incidences where more than one shop/outlet are visited within the development (also referred to as “cross-trade”)


Figure 6: Estimated traffic flows from the proposed development – Thursday

evening peak hour/total daily traffic flows (Interim Scenario)

Figure 7: Estimated traffic flows from the proposed development – Thursday

evening peak hour/total daily traffic flows (Ultimate Scenario)


The estimated future (year 2031) total weekday traffic flows on Abernethy Road, San Simeon Boulevard and Main Street have been sourced from the GHD January 2014 report and reported in the following table.

Table 1. Projected daily traffic volumes on adjacent road network

Road Section GHD modelling

projections Main Roads WA

projections Abernethy Road (adjacent to site) 12,950vpd 17,600vphAbernethy Road (W of town site) 8,050vpd 9,600vpdSan Simeon Road (N of Abernethy Rd) 4,010vpd 7,680vpdMain Street (adjacent to site) 5,020vpd 5,020vpd

7.4 Analysis of Site Accesses

The proposed two access system scenarios (interim and ultimate) for the subject development are discussed in section 3.0. The capacity assessment of the proposed two options of Abernethy Road crossover and Main Street crossover for the 2031 scenario which assumes full development of the BSP is undertaken to assess the suitability of the proposed access system to accommodate the anticipated development-generated traffic during the peak weekday period. The 2031 weekday peak hour through traffic flows on the three roads abutting the site have been sourced from the GHD January 2014 report. In the interim scenario both Abernethy Road and Main Street crossovers are proposed to operate as full movement crossovers while in the ultimate scenario Abernethy Road crossover is restricted to a left-in/left-out form. Both scenarios will be analysed in detail. For the interim Abernethy Road crossover a wide median and a right-turn pocket as shown in Figure 6 were also allowed for. As requested by the Shire, in both scenarios traffic from the Coles site was included in the assessment with the four-way mini-roundabout intersection on Main Street. In order to establish the anticipated traffic flows through this intersection Riley’s traffic assessment report dated October 2014 and prepared for Coles development was referenced. This report estimates that total weekday PM peak traffic generation of the Coles site will be in order of 725 trips (50/50 inbound/outbound split assumed). The directional distribution applied for this traffic is identical to that used in this assessment as described in section 7.2. Capacity analysis of the Abernethy Road and Main Street crossovers has been undertaken using the SIDRA computer software package for the year 2031 scenario. SIDRA is an intersection modelling tool commonly used by traffic engineers for all types of intersections. SIDRA outputs are presented in the form of Degree of Saturation, Level of Service, Average Delay and 95% Queue. These characteristics are defined as follows:


Degree of Saturation: is the ratio of the arrival traffic flow to the capacity of the approach during the same period. The Degree of Saturation ranges from close to zero for varied traffic flow up to one for saturated flow or capacity.

Level of Service: is the qualitative measure describing operational conditions within a traffic stream and the perception by motorists and/or passengers. In general, there are 6 levels of services, designated from A to F, with Level of Service A representing the best operating condition (i.e. free flow) and Level of Service F the worst (i.e. forced or breakdown flow).

Average Delay: is the average of all travel time delays for vehicles through the intersection.

95% Queue: is the queue length below which 95% of all observed queue lengths fall.

The results of the 2031 weekday peak hour SIDRA analysis for Abernethy Road and Main Street crossovers in the interim scenario are presented in Table 2 and Table 3 and discussed in the following paragraphs.

Table 2. SIDRA results for the Abernethy Road crossover – weekday peak period

(year 2031, interim scenario)


Table 3. SIDRA results for the Main Street mini-roundabout – weekday peak period (year 2031, interim scenario)

The results of the SIDRA analysis for Abernethy Road crossover and Main Street mini-roundabout indicate that very good overall LoS A can be expected at both intersections with ample spare capacity for future traffic growth. Accordingly, it is concluded that the proposed interim scenario access/egress system for the proposed retail development has the capacity to accommodate the traffic expected to use these crossover intersections during the peak weekday activity period in 2031. In the ultimate scenario Abernethy Road crossover is assumed to operate as a left-in/left-out only format and as such capacity issues are not anticipated so detailed capacity assessment was not undertaken. A capacity assessment for the Main Street mini-roundabout was undertaken for the ultimate scenario including the traffic from the Coles development as with the interim scenario. The result of the SIDRA capacity assessment for the ultimate scenario is presented in Table 4, overleaf. As with the assessment for the interim scenario, the result of the SIDRA assessment of the Main Street mini-roundabout for the ultimate scenario confirms that a very good overall LoS A can be expected at this access point.


Table 4. SIDRA results for the Main Street mini-roundabout – weekday peak period (year 2031, ultimate scenario)

7.5 Impact on Surrounding Roads

The traffic generated by the proposed retail development would contribute approximately 3,300vpd on adjacent roads. Considering the future traffic projections for the abutting roads identified in Table 1 the traffic from the proposed development would comprise a maximum of about 23% of Main Street traffic, 8% of San Simeon Boulevard traffic and up to 13% of Abernethy Road total daily traffic. According to the findings of the GHD January 2014 report, the forecast future daily traffic volumes are well within the proposed road standard and classification of the three roads adjacent to the subject site.

7.6 Impact on Intersections

The operation of the adjacent intersection of San Simeon Boulevard/Abernethy Road/Gordin Way for the year 2031 scenario have been analysed using SIDRA in the GHD January 2014 report. It should be noted however, that the San Simeon Boulevard/Abernethy Road/Gordin Way intersection was modelled as a four-way signalised intersection in this case in line with the local structure planning at the time. The result of the SIDRA analysis was sourced from the GHD report is presented in Table 5 and discussed in the following paragraphs.


Table 5. SIDRA results for the Abernethy Road/ San Simeon Boulevard/Gordin Way intersection – weekday peak period (year 2031)

According to the results of the GHD SIDRA analysis the San Simeon Boulevard/Abernethy Road/Gordin Way signalised intersection would be expected to experience overall LoS D during the peak weekday period in year 2031. The recorded vehicle queues suggest that there will be no flow-on impact from the intersection to the proposed site’s Abernethy Road crossover. In this instance the intersection recorded spare capacity in the order of 27%. The Shire of Serpentine Jarrahdale has engaged Jacobs to prepare design plans for the Abernethy Road upgrade to dual carriageway standard including design of relevant intersections. As part of the scope a number of SIDRA assessments for the intersections along Abernethy Road have been undertaken using the Main Roads WA traffic projections for the year 2031. Following the outcome of the recent three-party discussion between the Shire, Main Roads WA and the proponent regarding the future intersection of San Simeon Boulevard/ Abernethy Road/Gordin Way, which has endorsed a roundabout type of layout for this intersection, Transcore has undertaken a capacity analysis for the year 2031 adopting the following assumptions:

Intersection is modelled as dual-lane roundabout with dual lanes on Abernethy Road approaches and single lanes on San Simeon Boulevard and Gordin Way approaches;

Intersection is modelled using the same peak hour traffic volume inputs used by Jacobs for the year 2031.


Transcore’s modelled intersection layout is depicted in Figure 8 with the SIDRA assessment results for the typical weekday PM peak hour in year 2031 shown in Table 6.

Figure 8: Modelled Abernethy Road/San Simeon Boulevard/Gordin Way

intersection layout – dual lane roundabout


Table 6. SIDRA results for the Abernethy Road/San Simeon Boulevard/Gordin

Way roundabout (Transcore) – weekday PM peak period (year 2031)

The results of the SIDRA assessment for the Abernethy Road/San Simeon Boulevard/Gordin Way roundabout during the typical weekday PM peak hour in year 2031 indicates very good overall LoS A for the intersection with no notable delays or queueing on any approach to the intersection. The proposed roundabout intersection provides ample capacity for the future traffic growth (about 70% spare capacity). The result of the analysis undertaken by GHD, Jacobs and Transcore confirms that the future four-way intersection of Abernethy Road/San Simeon Boulevard/Gordin Way (either as traffic signals or a roundabout) would operate satisfactorily in 2031 with spare capacity available during the critical PM peak hour.

7.7 Impact on Neighbouring Areas

The proposed development is located within the planned Byford town centre extension area consisting predominantly of commercial uses. The planning for the area adjacent to the subject site is of commercial character with some public open space zones. Approach and departure routes to and from the subject site are predominantly on district level roads (65% of all traffic to the site is via Abernethy Road) and as such there is minimal potential for development-generated traffic to affect surrounding residential areas.


7.8 Traffic Noise and Vibration

It generally requires a doubling of traffic volumes on a road to produce a perceptible 3dB (A) increase in road noise. The proposed development constitutes nowhere near 50% of future traffic volumes on the adjacent road network so there would not be a perceptible difference in future traffic noise levels with or without the proposed development. The nature of the development is essentially of retail/commercial character and as such it will not generate significant traffic volumes late at night, so night time traffic noise and vibration are not anticipated to be an issue for this development either.

7.9 Road Safety

No particular road safety issues have been identified for the proposed development.


8.0 Parking

The total on-site car parking provision for the proposed development comprises 225 parking bays with four ACROD bays proposed to be located next to the main store entry and adjacent to T3 retail tenancy to ensure ease of access. The parking provision consists of 214 on-site bays and 11 embayed on-street parking bays along Main Street. The on-street component is proposed within the western verge of Main Street adjacent to the development. The loading dock with the dedicated service/delivery vehicle bay is located at the northern side of the main store building. The service vehicle would access the site via Abernethy Road crossover; negotiate the internal car park areas to access the loading area and egress via Main Street crossover. Refer Appendix E for turn path assessment plan. The turn path assessment at Appendix E indicates that some minor modification of the proposed plan would be required to accommodate the right turn swept path of the service vehicle but this is a matter that can be addressed at the detailed design stage. The parking requirements for the proposed type of the development are set out in the BTCLSP document (see extract from the report shown below).


9.0 Public Transport Access

The preparation of the Byford Structure Plan has involved liaison with the Public Transport Authority, who have developed the plan of potential future bus routes shown at Figure 9. As shown in the illustration the “Potential Bus Route 1” would pass next to the site along Main Street.

Figure 9: Planned future bus routes (source: Public Transport Authority)

It is unlikely that a bus station will be planned for Byford in the short to medium term. As explained in the GHD January 2014 report PTA has indicated that a bus station in Byford is unlikely to occur due to the transfer penalty from bus to bus and then bus to train at Armadale station. It is however left to be demonstrated that a case exists for the extension of Armadale train service to Byford once the patronage numbers are sufficiently high. A public transport hub is likely to be developed within the Byford town centre in the longer term following any extension of the rail line from Armadale to Byford.

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