Transport shapes urban growth

Transportation network planning is essentially a land use shaping exercise. Understanding of network planning principles is very crucial in efforts to improve public transport’s effectiveness measures such as destination accessibility, modal share, reliability, affordability and liveability (of well-connected nodes or corridors).

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Transport-Land Use Loop

Framework for Spatial Growth

A properly designed public transport network forms a strong organizing framework for spatial growth and development. A transportation network inevitably frames land use growth and development, which in turn generates travel demand that necessitates transportation network upgrades – the added capacity, speed and distance, creating a continuous transport-land use feedback loop.

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Iteration of land use and transport planning (adapted from Jarret Walker’s Human Transit)

Transportation is a tool to improve access among places of urban activities, and its planning need to correspond to land use goals – urban centers that would accommodate the greatest growth, green lungs that would need to be preserved, etc. In the same way, land use goals need to correspond to transport goals and constraints.

Thus, public transport network planning, regardless of mode, is a city building exercise that requires clarity in land use goals.

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The most basic building block towards metropolitan-wide transportation and urban growth network synergy starts at the street level (e.g. the humble bus, tram)

Nodes and corridors

Planning for public transport alignment and node placement has to consider both regional and local land use contexts.

Regional rapid transit is faster with less stop-and-go motions. Its alignment should consider nodal-based urban intensification, as proximity to stations offer superior regional access advantages. Frequent bus line is slower with closely-spaced stops, and its alignment should consider corridor-based mid-rise re-developments with greater pedestrian access advantages.

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Transit mode, route alignment and node placements should be planned to accommodate the desired urban density gradients that fit the surrounding land use fabrics and contexts

Purpose driven spatial and transport network

Urban public transport mode and alignment decision-making needs a wider metropolitan or conurbation growth and transportation perspective, as these elements are highly interconnected in nature. Modelling of efficacy of a new transportation proposal (e.g. new highway or rapid transit) requires careful deliberation of variables that affect spatial and travel demand components:

  • Concentration of urban growth (which attracts trips) in walkable areas where frequent public transport intersects
  • Intensification and diversification of urban neighbourhood (which generates trips) along frequent public transport corridors
  • Transit priority measures to increase public transport competitiveness through lowering opportunity cost of travel (e.g. shorter door-to-door travel time)
  • Travel demand management measures to decrease private vehicle competitiveness through increasing opportunity cost of travel (e.g. higher road and parking charges, higher spatial and temporal parking/access restrictions in dense urban areas)
  • Control of metropolitan sprawl from leap-frogging the existing greenbelts through Urban Growth Containment Boundary and limitation of freeways
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Land use and transportation components interact with each other in a never-ending-loop, and transport modelling is frequently used to quantify the future impact of new transport initiative based on a combination of transport network (re-)configuration, land use (re-)profiling, and sampled travel demand data (i.e. road-based traffic volume and speed, activity-based trip origin, destination, mode, time and purpose, and land use-based trip generation)