Transport appraisal guidance and economic density
A study to scope out future updates to agglomeration guidance in transport analysis g guidance (TAG).
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This study sets out the scope for a large-scale re-estimation of the agglomeration parameters applied in the Department for Transport’s (DfT) transport analysis guidance (TAG).
It is covered in 2 parts. The first is a scoping study that reviews developments in research on agglomeration and transport appraisal and how it can be incorporated in a future re-estimation of TAG. This includes:
- areas of improvement for the wider economic impacts (WEI) assessment framework
- 2 main types of agglomeration economies in appraisal calculations: urbanisation economies and localisation economies
- how amenity and consumption factors are appraised, including wider relocation costs within TAG
The second part provides an assessment of the current economic model used to calculate the WEI of agglomeration in transport appraisal. It focuses on potential sources of overlap with other elements of appraisal.
TAG provides information on the role of transport modelling and appraisal, and how the transport appraisal process supports the development of investment decisions to support a business case.