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Figure: Source: Melanie Bosredon PhD Upgrade, The evolution of Land-Use/Transportation Interaction modelling

Land-use / transport interaction models (LUTI) are a common tool for planners to analyse the impacts of new policies on urban systems. They can be used to test new transport schemes and/or new land-use developments in order to estimate the impacts on land-use activities and accessibilities over time. There is a strong relationship between transportation and land-use; they mutually influence each other over time.

There are a wide variety of models used to simulate transport movements within urban environments. The development of such models has been ongoing for a number of decades, as shown in the figure below, with the model types evolving as knowledge and computational power have advanced.

At CASA, a team of researchers has expertise in this field, and the following research is currently being developed:


Activity Location Modelling

Figure: Simulacra simulation of airport location impacts
Figure: Simulacra simulation of airport location impacts

A large-scale activity-location model of the Greater London region is being developed in which all stages of the model-building process—from data input, analysis through calibration to prediction—are rapid to execute and accessible in a visual and immediate fashion. The model is structured to distribute trips across competing modes of transport from employment to population locations. It is cast in an entropy-maximizing framework which has been extended to measure actual components of energy—travel costs, free energy, and unusable energy (entropy itself)—and these provide indicators for examining future scenarios based on changing the costs of travel in the metro region.

Although the model is comparatively static, we interpret its predictions in terms of fast and slow processes—‘fast’ relating to changes in transport modes, and ‘slow’ relating to changes in location. After developing and explaining the model using appropriate visual analytics, a scenario in which road-travel costs double is tested: this shows that mode switching is considerably more significant than shifts in location—which are minimal.


Sustainability Modelling

This research suggests a conjunction between three components: the capability approach, urban sustainability, and LUTi modelling. The first, the capability approach, is more a theoretical framework, within the domain of political philosophy. The second, urban sustainability, is a topic within the relatively young scientific domain known as sustainability science. The third one, LUTi modelling, is a topic within the scientific domain known as science of cities.

The first component, the capability approach, within political philosophy, refers to a broad normative framework for the evaluation and assessment of well-being2 pioneered by economist and philosopher Amartya Sen. The capability approach is not a theory that can explain well-being; instead, it provides a flexible and multi-purpose framework that can help to conceptualize and evaluate this phenomenon. The capability approach suggests that freedom to achieve well-being is a matter of what people are able to do and to be, and thus the effective freedom to lead the kind of life they value to live.

The second component, urban sustainability, within sustainability science, refers to the promotion of improvements in well-being of individuals living in cities and their hinterlands under moral constraints of respecting the options for achieving an acceptable well-being elsewhere in space and later in time; while conserving the resources and services provided by the urban system, taking into account the influence of human actions on the earth’s life support system at different spatial and time scales.

The third component, LUTi modelling, within science of cities, refers to the set of mathematical and com- puter model-building techniques used to understand human interactions and human activities participation to inform policy-making in order to provide the underpinnings of improvements in well-being of individuals living in cities. LUTi modelling focus primarily on the way populations and employments locate in urban space consistent with the spatial interactions between different locations of these activities. The aim of LUTi modelling can be described as the understanding of how the spatial distribution of human activities influence travel needs, mobility patterns, and the evolution of transport infrastructure; and how the transport system, in turn, influences where people engage in activities and how the urban form changes.

While there are already some links between urban sustainability and LUTi modelling as well as between urban sustainability and the capability approach; the suggested link in this research between LUTi modelling and the capability approach, and the subsequent suggested conjunction between urban sustainability, LUTi modelling and the capability approach are novel.

In summary, the aim of this research is using LUTi modelling to understand individuals interactions and the dynamic feedbacks loops and pattern formation of individuals activities participation can provide the means to model evolutionary changes on the substantive content of well-being from the perspective of the capability approach to delineate and measure dimensions of urban sustainability.


Figure: [Sustainability graphic]
Figure: [Sustainability graphic]

Energy-related Modelling

The Intergovernmental Panel on Climate Change is predicting the average temperature to increase by two degrees. This will lead to a change in the use of energy in most large cities. The form of cities would change as the population adapts to these impacts in terms of location, land-use and travel patterns. MECHANICITY seeks to contribute to the science that ahs to be develop so that we can assess such impacts and plan for them. In spatial interaction modeling, energy is explicit in terms of transport but not central.

Source: ©David Simmonds Consultancy Ltd
Source: ©David Simmonds Consultancy Ltd

The aim of the research we are undertaking here is to understand the changes in the morphology of cities over time resulting from the forecasted changes of energy costs – costs that are related to household expenditure (commuting costs, electricity and gas consumption…). In Greater London, those costs are increasing significantly while incomes are stagnating. As a result many households may struggle in the near future to continue living the same way they are now and may need to modify their behaviour regarding transport choices or decide to relocate somewhere.

We are using the DELTA package that has been developed by David Simmonds Consultancy Ltd to incorporate energy costs related to household budgets. DELTA is a land-use/economic model, which can be linked to any appropriate transport model. It’s a dynamic model that works at both urban (within-city) and regional (between cities) levels.

The figure here gives an overview and the main DELTA components: