• Modeling complexitywith PTV Vissim

    Modeling complexity
    with PTV Vissim

Atkins: New Oxford Circus

 

Project title:
New Oxford Circus, London, UK


Contracting authorities:

  • The Crown Estate
  • Transport for London (TfL)
  • Westminster City Council

Branch/sector: Public Authority
Contractor
: Atkins
Project duration:
12 months

Project description:
PTV Vissim was used to model the Oxford Circus junction in London as well as surrounding highway network as part of a scheme designed to significantly improve the Public Realm both at the junction and in the immediate vicinity of the junction including the introduction of diagonal pedestrian crossings. Base models of the existing highway network were first created, calibrated and validated according to TfL standards. Testing was then undertaken to assess the impact of changes to the junction on the different types of vehicles using the junction and with particular regard to bus journey times. The model was then adjusted to reflect the proposed changes to the road network and proposed signal timings were taken from a parallel TRANSYT model. Overall, the Vissim models illustrated that the proposed changes would not be detrimental to the operation of the network with the key findings being:

  • On a typical day all traffic passing through the junction will still be able to do so (with the exception of the traffic from Princes Street, a side road to the south which was proposed to be closed)

  • Very little change in bus journey times was predicted to occur with average journey time improvements of 7 to 15 seconds predicted for buses.

  • Very little change in the journey times for other vehicles was predicted to occur with changes ranging from +3 and -8 seconds.

  • The length of traffic queues was predicted to be similar to lengths before the proposed scheme. Although small increases in queue lengths were predicted for some approaches this was offset by the relocation of the stop lines at Oxford Circus which provide greater ‘stacking space’ between the Circus and adjacent junctions. The probability of queues ‘blocking back’ was therefore deemed to be similar to the original traffic operation.

Software & modules used: PTV Vissim
Further information:
Atkins