Transport for the North’s vision is of a thriving North of England, where world class transport supports sustainable economic growth, excellent quality of life and improved opportunities for all.
In the Technical Assurance, Modelling and Economics (TAME) team, our job is to provide a quantitative assessment of how much TfN’s Investment Programme and other supporting policies will help to achieve this vision. This isn’t an easy thing to do, but we’ve made good progress over the past three years, and now we’ve launched a new webpage as a platform to share information on our work so far.
We’ve been busy developing, testing and applying the Analytical Framework, a new suite of software tools that provides a consistent approach to data, modelling and appraisal across travel modes and regions of the North.
The Analytical Framework was initially developed to provide bespoke modelling tools to support the business case for Northern Powerhouse Rail (NPR). A major national infrastructure project like NPR needs tailored, high quality, innovative modelling to give confidence to decision makers that the scheme’s impacts have been comprehensively and robustly estimated.
In the TAME team, we’ve used our work to support NPR as an opportunity to build a new digital asset for the North – the Analytical Framework.
Why develop the Analytical Framework?
There are a lot of transport modelling tools out there already, so why did we decide to develop a new system? As a new tier of regional governance, it’s vital TfN activities add value over and above the excellent work Local Authorities and national organisations already do. For the Analytical Framework, this meant tackling some challenging areas, like:
developing tools that can balance local detail with regional scale;
modelling the whole regional transport network, including road and rail, passenger and freight;
capturing transformational wider economic and social impacts;
representing the impact of non-transport policies (e.g. land-use); and
realising economies of scale by making our data and tools sharable with local partners and stakeholders.
This list includes quite a few competing requirements that are tricky to balance, so we needed to develop an approach that was flexible, whilst also maintaining some strong guiding principles.
Based on this thinking, we’ve developed an interconnected framework of analytical tools – not a single overarching simulation model, or a series of smaller independent models.
Why did we decide to design it in this way?
There are several reasons why we decided to design the analytical framework in the way we have.
One model would be too big. It’s quite easy to build a transport model that takes days or even weeks to run by adding more and more detail. The problem grows even more rapidly if you want to use the model to look at multiple transport modes or interactions with the economy and land-use. This is no good if you’re trying to optimise the design of some new infrastructure, or test how well it works in multiple different future scenarios. Our approach has been to split the model into a tiered framework, with different tiers focusing on their own specialist area.
We’ve taken a ‘system-of-systems’ approach. Each tier of the Analytical Framework focusses on its own system. Tier 1 represents the economy and land-use system. Tier 2 represents the transport system. To show the transformational impacts of transport, we needed to represent the fact that these two systems interact, so we set up flows of data that allow us to approximate the feedback loops between them. We can develop the two tiers separately, as long as we maintain a consistent set of touchpoints between them. This approach also allows us to add more systems later if needed, for example, to explore the interaction with the electricity system as uptake of electric vehicles grows to meet our decarbonisation commitments.
Consistency is important. The different tiers of the Analytical Framework need to be built from consistent data and assumptions to ensure appraisal results are produced on the same basis. Inconsistency between different models can raise questions and make it more difficult to develop a strategic narrative from the modelling results. The system-of-systems approach meant we had to address consistency issues head-on when developing the touchpoints between the modelling tiers, which has improved our ability to generate strong narratives from the Analytical Framework.
Automation and interoperability are enablers. The system-of-systems approach involves passing data between different tiers, which could potentially be messy and time consuming. We’ve avoided this problem by sticking to some key principles that allow automation and interoperability. We use a small number of common file formats, are developing a common data model, and use Python as the common coding language for automation processes that pass the data around avoiding the need to do this manually.
What does the Analytical Framework look like?
At this point, you’re probably thinking that these principles make sense, but you’re still not sure what the Analytical Framework actually looks like.
This needs a diagram, so we’ve created this new page of the TfN website, which allows you to explore the Analytical Framework and its features.
The main high-level features of the Analytical Framework are spilt into four sections and cover key areas of TfN’s work.
Data. The Analytical Framework is underpinned by detailed spatial datasets from a range of sources. We combine these datasets together to produce estimates of population and employment by area and segment (e.g. employment status and socio-economic group). This detail allows TfN to understand how future changes in the population and employment mix in the North could affect travel patterns and how much different groups of people will benefit from TfN policies and investments.
Future Travel Scenarios. TfN’s Future Travel Scenarios are used to explore how different uncertain trends in society, the economy and national policy could influence the level and distribution of travel demand in future. TAME represents the Future Travel Scenarios quantitatively in the Analytical Framework as different future patterns of travel. This allows different investments in the transport network to be tested in the Analytical Framework under different levels and distributions of demand, helping to understand what would need to happen in future for these investments to be most beneficial.
Forecasting System. The Forecasting System uses simulation modelling approaches to estimate how transport users, households and businesses will respond to changes in the transport network. It includes the Northern Economy and Land-Use Model (NELUM), TfN’s tool for representing transformational changes to the economy and land-use in response to significant improvements in transport connectivity. The Foresting System also includes the Northern Transport Modelling System (NorTMS), TfN’s key tool for understanding how people move through the transport network, enabling an understanding of door-to-door journey time and quality, capacity issues and operational performance.
Appraisal System. The Appraisal System processes outputs from the Forecasting System to help us value the estimated impacts of each project. Appraisal is the process of weighing up the benefits, costs and other impacts of proposed transport projects to help choose a preferred option. We use a Multi-Criteria Appraisal Framework, aligned to our Strategic Transport Plan objectives, which uses a large number of quantitative outputs from TAME’s Appraisal System, as well as other qualitative assessments of impacts. Impacts quantified include transport user benefits, wider economic and social impacts and environmental impacts.
What do these new tools mean for the way TfN approaches developing transport strategies and business cases?
There a few important things these tools help us to do, including identifying current and future transport network problems and providing new insight into where investment is needed.
They will also make the case for investment with improved robustness – building Government confidence in using evidence from Analytical Framework to support new investment decisions.
The case for levelling-up will be made clearer by showing how benefits to the North help the UK overall and identifying the investments that will make growth socially inclusive and economically sustainable.
And the tools will show how the North can achieve a thriving zero carbon economy demonstrating what policies and investments in the transport network are needed to balance our economic and environmental ambitions.
It’s not just TfN’s work that will benefit from the development of these tools. Analytical Framework datasets and models have been developed by TAME to be used as widely as possible by transport analysts and planners in the North, particularly our Local Authority Partners.
Our aim is to improve the quality and consistency of modelling and appraisal across the region to help inform decisions at a local as well as a regional level.
We’re working towards making some of our datasets, interactive visualisations and modelling tools freely available online during 2020. We’ve been relatively quiet about this work until now, but we’re getting ready to start sharing and we’ll be posting more updates on this over the next few months.
