No Black Boxes Please, We’re Decision-makers! A Sketch-modelling Approach to Mass Rapid Transport Demand Estimation
Sharon Biermann, The University of Western Australia, Doina Olaru, University of Western Australia, Gary McCarney, University of Western Australia
A sketch model is compared to a strategic four-step model in estimating rail patronage demand in Perth, Australia. It is found that sketch-modelling is a viable, alternative tool but sensitivity analysis and validation are essential.
Simpler, sketch-planning model approaches are recognised as being suitable for use in longer term planning as an initial means of selecting possible solutions for later, more detailed investigation, facilitating analysis at a coarse level of resolution without the excessive data needs and rigid assumptions of more conventional computer models. In practice, however, it is common for transport planners to revert to more traditional, four-step transport models for patronage demand estimation, even at the early stage of the process when a range of high level network options are being explored. Initial, strategic visioning stage are consequently often hampered by largely technical and data demands of the modelling machine. With reference to a case study application of a sketch-planning model to estimate mass rapid transport patronage demand in the Perth metropolitan area, the aim in this paper is to compare the efficacy of the use of the sketch model with that of a strategic four-step model in relation to inputs, outputs and acceptance. The demand estimation was used as part of the process to advise on the need for augmentation of the peak daily capacity of the present mass rapid transit system for an anticipated doubling of the population to 3.5 million within a period of three to four decades. It is concluded that for the purposes of the initial, network option exploratory iteration of the planning process, the sketch-planning model can be a viable, alternative tool to quickly but systematically, consider a range of initial patronage demand scenarios for later, more selective, detailed and thorough investigation. Sensitivity analysis and fit-for-purpose validation are essential requirements to ensure the maximum level of accuracy and minimum level of risk and uncertainty for the given boundary conditions.
Association for European Transport