The Jubilee Line Extension (JLE) represents the largest investment in urban rail in the UK for decades, and was justified economically in part on its non-transport benefits (e.g. urban regeneration). London Transport are interested in identifying the full range of impacts of JLE on the local community and in the wider sub-regional context, and have set up a Co-ordinating Unit at the University of Westminster to act as a focal point for the many studies that are underway or planned. This paper describes the methodological framework that has been devised for the research, and the set of studies and surveys that are being commissioned by London Transport to identify the main kinds of impact that have been identified. It begins by briefly presenting key findings from a review of previous impact studies, highlighting the lessons that have been learnt, both in terms of methodological success and failures. Next, it discusses several fundamental issues that are central to the development of an appropriate impact assessment framework, including: (1) the need to separate impacts from changes, and to distinguish these from simple differences over time; (2) the use of control or reference areas; (3) the spatial and temporal extent of the expected impacts (in the latter case, including the question of how far back in time to start to look for impacts); and (4) the use of qualitative and quantitative approaches to identifying causation. The paper then summarises the range of indicators that are being used to measure changes, and the process by which impacts will be ascribed to JLE and other factors, using a baseline scenario as a reference point. Finally, the paper documents the set of core studies and surveys that are being commissioned by London Transport (ranging from transport/traffic, through economic regeneration, to townscape), and shows the main timescales and interrelationships.
Abstract