5 Model Development
5 Model Development
Key Achievements
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5.1.1 This chapter focuses on the work undertaken on the development of TMfS during 2008. Particular focus will be on the development of the new National Model, TMfS:07.7 This section will also reflect on the various other versions of TMfS that have been produced in the previous year to meet the needs of the User Group. These include:
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5.1.2 Each of these models and the associated developments are discussed in light of the 2007 commitments outlined in Table 5.1 below:
Table 5.1 Model Development Objectives
Objectives |
Development of Enhancement Report model development commitments Delivery of TMfS:05a, including Ayrshire and TACTRAN RSIs Delivery of Phase II of the Highland Model Development of TMfS:07 Provision of TMfS:07 progress note in this Annual Report Creation of regional models |
5.1.3 The remainder of this chapter considers the model development programme in chronological order of model release.
5.2.1 The incumbent version of TMfS in 2007, TMfS:05, did not cover all of mainland Scotland and did not include a representation of ferries. Given the requirement that the Strategic Transport Projects Review (STPR) consider potential transport interventions across all of Scotland, it quickly became apparent that an interim version of the model was required before the release of TMfS:07 in 2008.
5.2.2 TMfS:05a includes all of the functionality of TMfS:05 as well as some ‘quick win’ enhancements designed to meet the immediate needs of the STPR team and the TMfS User Group more generally. Most notably, TMfS:05a has seen the extension of the model to cover the whole of the Scottish mainland, while a representation of domestic ferry services was also included in the model.
5.2.3 The model has benefited from additional data not included in TMfS:05. Most notably, a number of RSIs were included in the Highlands, so as to provide an initial representation of travel demand. New RSIs were provided for the TACTRAN and Ayrshire areas, thus replenishing the older data contained within TMfS:05. Consistent ‘Do Minimum’ and ‘Reference’ cases for 2012, 2017 and 2022 were established.
5.2.4 A number of technical enhancements were made prior to the release of TMfS:05a, including:
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5.2.5 TMfS:05a was made available in October 2007 and has been used on a number of key applications during the previous year, including the STPR, Glasgow City Plan II and the Scottish Climate Change Programme. Support for TMfS:05a will continue throughout, although it is envisaged that any new applications will be taken forward using TMfS:07.
5.3.1 The Highland Model is a stand-alone sub-area of TMfS which was specifically designed to meet the needs of the STPR. The model provides a better representation of the demand for travel in the key mainland transport corridors (A9, A82 and A96), which were not covered by the previous release version of TMfS, TMfS:05.
Overview
5.4.1 Another key requirement of TMfS is to deliver, maintain and support an enhanced version of the model that coincides with the current and future policy requirements of the TMfS User Group. As a progressive step, a new model, TMfS:07, is now available. The broad specification of TMfS:07 was sketched out in the TMfS Enhancement Report, which was published in January 2007 and refined thereafter. Model development continued throughout 2008. This section outlines some of the key features of the new modelling suite.
5.4.2 A key feature of TMfS:07 is the new hierarchical approach adopted in model development, with a high-level national model and more detailed regional Sub-models. TMfS:07 is known as the ‘National Model’ and will become the standard release version of TMfS henceforth. Over time, TMfS:07 will be supplemented by more detailed regional models, the first of which is the new Forth Regional Model. This is an important step in the wider context of transport modelling in Scotland. For the first time, TMfS will be designed in a fashion that is truly commensurate with its role as a national model, while the more detailed regional models will provide a link between strategic and less strategic modelling.
5.4.3 The first regional model will be of the Forth area. Jacobs Consultancy and Arup are using TMfS to assist in the design of the Replacement Forth Crossing and, given the magnitude of this project, it was agreed that a more detailed model of the Forth Valley was required.
5.4.4 In line with TMfS:07 being more strategic than its predecessor, TMfS:05a, a number of changes in model form have been made, including:
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5.4.5 This new approach provides a more proportionate distribution of zones between urban and rural areas and allows for quicker run times.
Data
5.4.6 TMfS:07 has benefited from the inclusion of a significant volume of new data. These data are more fully elaborated upon in Chapter 6. However, key areas of data collection include:
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Technical Enhancements
5.4.7 A number of the technical enhancements proposed in the TMfS Enhancement Report have been brought forward, firstly in TMfS:05a and latterly in TMfS:07. The TMfS:05a-based enhancements are described above. However, additional TMfS:07 enhancements include:
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5.4.8 A full review of the development of TMfS:07 can be found in the TMfS:07 Model Development Report.
5.5.1 The development of TMfS has made an important contribution towards encouraging model applications and thus delivering the Scottish Government’s Purpose. As noted in Chapter 2, it is the actual application of the model that delivers value. However, the quality of each application is itself dependent on model development and data collection.
5.5.2 TMfS:05a and the Highland Model provided an invaluable ‘off-the-shelf’ toolkit for the STPR team. TMfS:05a also provided valuable enhancements to TMfS:05, including the ability to assess ‘Wider Economic Benefits’ and better evaluate the environmental impact of schemes. This ensured that this key project was underpinned by consistent and robust evidence. TMfS:05a was also subsequently used on a number of other important applications spread across different policy areas. As with the STPR, the provision of a consistent tool that can be used to devise policy ensures a coordinated approach which assists in delivering the Government’s Purpose.
5.5.3 TMfS:07 represents a step change in the quality of the model with a number of technical enhancements and a considerable quantity of additional data. TMfS:07 and TELMoS:07 will form the standard release version of the model for the foreseeable future. The enhanced functionality of the model and updated dataset will allow for more detailed and robust analysis. As a result, the model is likely to have a central role in shaping Scottish transport policy in the foreseeable future. Such a role would add value to TMfS and allow a more effective measure of the impact of interventions on the Government’s Purpose.
5.5.4 The Forth Model will also play an essential role in transport’s contribution towards the Government’s Purpose and is an important step in the reorganisation of the transport modelling hierarchy in Scotland. The provision of the Replacement Forth Crossing is a central element in ensuring the vibrancy of Scotland’s economy in the future and TMfS will play an important role in developing the project.