Wembley Sports Park Integrated Access, Traffic and Car Parking Plan

AECOMWembley Sports Park Integrated Access, Traffic and Car Parking Plan40Figure 19Proposed Roundabout LayoutTable 10Performance Summary for Main Intersection (Roundabout Option)TimeDayDemand Flow(vph)OverallDoSAverageDelay (s)LoSApproach /MovementWorst MovementDelay(s)11:00-12:00 Winter Sat 3,087 0.614 8.5 A West / RT 16.4 6.014:00-15:00 a Winter Sat 3,300 0.739 11.6 B South / RT 18.1 8.2PM Peak Weekday 3,126 0.649 6.2 A West / RT 17.2 2.2Queue(m)Notes:a With additional traffic diverted from Salvado Road EntranceFrom Table 10 it can be seen that a roundabout will offer higher performance to that of a signalised intersectionand is expected to have a smaller likelihood of serious injury or fatal traffic crashes. It also provides a solution foru-turns to the north to access properties and to the south to access the Wembley Sports Park (over and above theright turns into the Wembley Sports Park). However, it may not achieve other objectives such an accessrestriction and enhanced pedestrian crossings. Additionally, it may also be more difficult to develop its designconsidering the property constraints especially on the west side of Selby Street.5.8 Comparison of Intersection TypesTraffic analysis has been carried out for both a signalised intersection and a roundabout at the main access.Whilst the roundabout demonstrates slightly better operational performance than a signalised intersection, thereare a number of advantages of providing traffic signals at this location.A roundabout provides the most efficient solution for traffic and once installed has much lower maintenancerequirements and costs than a signalised intersection, but this is often offset by increased construction costs. Inaddition, roundabouts offer very poor facilities for pedestrians and cyclists, with minimum protection at crossingpoints and in general, greater crossing distances. It is also difficult to provide a design that can ban movementsfrom certain arms of the intersection without also removing the opportunity to make those turns from otherapproaches. This is critical when considering the potential for ‘rat running’ through Alderbury Street.Roundabouts also require a much larger footprint than an equivalent signal controlled intersection. The currentlayout at Selby Street / Alderbury Street is quite constrained and in order to accommodate a roundabout withsufficient lanes on each approach, a significant amount of land take would be required. This may impact uponprivate properties or if that is to be avoided, result in significant land take and realignment of Selby Street on itswestern side, significantly increasing costs.T:\60218676 - Wembley PK TA\8 Issued Docs\8.1 Reports\Comprehensive Integrated Access RevF.docxRevision F - 8 February 2012