Wembley Sports Park Integrated Access, Traffic and Car Parking Plan

AECOMWembley Sports Park Integrated Access, Traffic and Car Parking Plan425.9 Internal Road JunctionAn assessment was also undertaken for the internal junction on the East-West Link with the south western carpark. A review of the junction highlighted several possible intersection treatments for this junction including:1. Unsignalised junction allowing all movements;2. Unsignalised junction with banned movements; and3. A roundabout.Due to the high volume of traffic entering and exiting this junction, particularly to and from the south western carpark, it is important to determine the most suitable junction layout that is safe and provides good access.Unsignalised Full Access OptionA SIDRA assessment of an un-signalised full access junction showed that it would perform well during both thearrival and departure peaks. However, these results do not include any impacts that the signalised intersection atSelby Street / Alderbury Street would have on this junction. From the SIDRA assessments of the main entrance,the results show that queuing of over 200m could exist on the East-West Link particularly during the departurepeak. This queue length would extend across this car park access; therefore SIDRA results for the un-signalisedfull access junction were not accurate.VISSIM micro simulation highlighted an issue with the right turn pocket on the East-West Link. To provideadequate separation between the signalised junction and the right turn into the car park, 3 seconds of travel timeshould be provided before the turn pocket develops. At 30km/h, this equates to 25m. Due to the limited distancebetween the two junctions, the provision of a separation distance of 25m is not possible.Unsignalised with Right Turn BansAlternatively the right turn into the car park could be banned. This option forces all vehicles to continue along theEast-West Link and undertake a u-turn at the roundabout. Micro-simulation shows that the right turn ban wouldimprove the operations between the main access and the junction to the car park. From the VISSIM microsimulationresults it is further expected that the introduction of the u-turn operations could be accommodatedwithout causing flow break downs on the East-West Link.RoundaboutThe third option for this junction is to install a roundabout. Roundabouts require a larger footprint than an unsignalisedjunction however it caters for all movements and does not require a right turn pocket. VISSIM microsimulationshows that the roundabout would cause similar queuing problems to that experienced in the full accessoption.5.10 Internal RoadVISSIM micro-simulation was used to assess the traffic operations on the East-West and North-South Links. Thiswas done to test the interaction between the various components along these roads. Key findings from theassessment include:- For safety and operational reasons, right turns cannot be allowed at the access from the East-West Link tothe southwestern car park. Vehicles queuing to turn right into the southwestern car park on the east-westlink road could block traffic entering from Selby Street, potentially impacting upon the operation of SelbyStreet, but also restricting access to drop-off facilities. As mentioned earlier, these right turns can beaccommodated via u-turns at the roundabout located at the eastern end of the East-West Link without anyadverse impact on the internal or external road network.- At the estimated drop-off rate and under normal conditions, the drop-off facilities are not expected to causeflow breakdowns on the East-West Link. The induced u-turn traffic flow, even though fairly congested duringthe peak Winter Saturday events, is expected to be below capacity.- The North-South Link from Salvado Road to the roundabout will perform an important circulation function,particularly during the peak Winter Saturday events. Flow breakdowns are expected to occur if thesevehicles are channeled directly through the Stage 1 northeastern car park. Additionally, without the southernportion of the link, traffic entering the car park from the south would not be able to make u-turns and wouldbe forced to exit at Salvado Road. For operational flexibility and efficiency the entire North-South Link istherefore required in both Stage 1 and 2.T:\60218676 - Wembley PK TA\8 Issued Docs\8.1 Reports\Comprehensive Integrated Access RevF.docxRevision F - 8 February 2012