Transport modelling

Transport modelling is a fascinating blend of fields such as transport planning, engineering, data science, behaviour science, and more. It uses math and computers to understand how transportation systems work, critical for making smart decisions about land use and infrastructure investments.

In a recent review of transport modelling in the South East region, we found that all local transport authorities have access to models covering their areas. However, many authorities feel they don't have enough expertise to use these models effectively and rely on consultants. This can be overwhelming, especially considering the costs involved.

So, why bother spending all this money on what seems like a ‘black box’? Let's break it down into two questions: Do we really need a model to help us plan transport? And do we have to spend a fortune to get one?

Consider this: Have you ever used Google Maps to plan a trip? Congratulations, you've experienced a basic form of transport modelling! Whether it's plotting the quickest route, estimating travel costs, or identifying a preferred shop for a stopover, it's all a testament to the power of modelling. While for a local journey you may rely on memory, even that is a form of 'modelling' based on “data” - past experiences.

What would happen without these “models”? You may find yourself in the wrong place or having spent significantly more time and effort than necessary. While this may not seem like an immediate concern on an individual level, in the realm of transport planning, such oversights can have significant repercussions. We cannot afford to invest in infrastructure projects only to later realise that it generates more issues than benefits. A robust transport model aids in testing our plans, ensuring that we identify optimal solutions within the intricate framework of the city's transportation system.

There are various types of models (e.g. strategic, mesoscopic, microsimulation, machine learning, AI), each with its own complexity and purpose. While a comprehensive review of modelling would require a doctoral thesis, let's simplify matters by envisioning the analytical framework as building blocks within a pyramid.

At the core of this framework (Level 1) lies data—the foundation for everything else. A model without good quality data to train and validate is not different from an expensive video game. Next comes the model itself. There are simpler models (Level 2) that simulate what we observe, such as traffic flow or journey time, and more complex ones (Level 3) that delve into root of problems. These often integrate a number of simpler models from Level 2, for instance, the Variable Demand Model to simulate how and why a specific group of people travel in observed patterns. Nowadays, with AI models, we're predicting outcomes faster than ever before. However, there is a catch: despite their speed and accuracy, interpreting the results of AI models remains challenging for even modellers.

Advancing up the pyramid, we have tools for policy formulation and decision-making (Level 4). These tools leverage the model's output to assist in decisions such as whether to build new roads or improve public transport. Lastly, at Level 5, we develop the means to share and disseminate analysis results.

Now, to the second question: Must we break the bank to develop an analytical framework? Not necessarily! Many of the tools, or at least the methodology for developing the tools, already exist and are documented in a machine-readable language. The key lies in obtaining the right data and employing appropriate tools. You wouldn’t want to use sledgehammer to crack a nut, or even worse, a peanut! This is where we can assist. At TfSE, we're dedicated to supporting our partners, whether as a “Contributor” bridging gaps in data availability, or as “Product Owner” leading the development of models and tools in optimal form.

We are fully aware of that this does not mean, as a local transport authority officer, you no longer need to build or manage a local transport model. However, this will reduce the time and, therefore, the costs for building or updating your local transport model. Additionally, we hope this provides you with resources to better understand your local models and tools. All you need to do is talking to us about your needs. The Regional Centre of Excellence and the South East Transport Modelling and Appraisal Forum are the two of example flatforms that we have provided for you to contribute to and benefits from what we do here at TfSE.

In conclusion, while transport modelling may seem daunting, it remains essential for making evidence-based decisions to shape the future of our cities. By collaborating and utilising the right tools, we can make informed decisions and create more sustainable transportation systems. If you have any questions about our analytical framework, please don't hesitate to reach out to us.