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Effects and affects of urban change and urban management

Urban and transport infrastructure does not remain stagnant over its whole lifecycle. Many cities across Europe are over 1000 years old (London, UK; Paris, France). Other cities around the world are hundreds of years old (New York, US; Sao Paulo, Brazil). These cities have seen continuous growth over their lifecycle to date with the provision of urban and transport infrastructure to cater for their increasing size and urban economics.

As cities become denser and thus busier, there can be a trend of people moving out of the city to suburbs where environments are less congested and potentially have a more relaxing environment. Hillingdon, in Greater London, is one such example. Before the construction of the Metropolitan line, n the early 20th Century, the Hillingdon LU station area was open fields, with a local road between the villages of Ickenham and Hillingdon (Fig.1).

When the Metropolitan line was constructed in the early 20th century (1904) there was no urban development in the immediate environment of the railway, so a metro station was not provided, Fig.2. By 1923, urban expansion had seen the development of housing and the provision of a metro station to enable travel into central London (Fig.3). The environment to Hillingdon London Underground station was to remain this way until the 1990s, when the need for improved highway facilities was to change the area shown in Figs.1-3, forever.

Fig.1: Historic OS Map, showing the Hillingdon London Underground station area, before construction of the railway. Note the local road, running north to south. The purple line represent the alignment of the Metropolitan line.


Fig.2: Historic OS map, showing the Hillingdon London Underground station area, post railway construction. Note there is no station and no urban development.


Fig.3: Historic OS map, showing the Hillingdon London Underground station area, between 193 and 1940. Note the provision of housing, the stations and the goods yard.


By 1994, increased levels of vehicular traffic travelling to and from London,  saw the construction of a new trunk road, linking London to the west (Oxford). Construction of the trunk road saw the relocation of the metro station to a new site, west of its previous location, and the diversion of the existing local road on to a new alignment. (The curved road, running top to bottom in Fig.4).

To accommodate existing users of the metro and the original local road, the new transport infrastructure (the station and new road) had to be provided alongside the existing infrastructure before it could be replaced. Hence the curving alignment of the new road between Ickenham and Hillingdon, today.

Fig.4: TfL Aerial image, showing the Hillingdon London Underground station area, c.2017. Note the alignment of the road between Ickenham and Hillingdon due to the need to keep the original road open as long as possible before the opening of the new local road. Also note the relocation of the station. All to make way for the new trunk road. Source: Transport for London.


As the UK Highways Agency were the proposers and constructers of the trunk road, which caused changes to the environment shown in Fig.4, it was the responsibility of the Highways Agency to pay for and maintain the new infrastructure.

An exception was made for the railway bridge carrying the Metropolitan line over the new trunk road, which was vested into London Transport (predecessor to London Underground). The exception was due to the risk to the safe presence and operation of the metro infrastructure (future proofing) from another transport stakeholder taking responsibility for its maintenance and repair. As such, the risk of maintaining that safe presence and operation of the bridge was retained by London Transport and its successors, whilst other agencies (Highways England and Hillingdon Borough Council) subsequently took responsibility for the other roads and bridges interfacing with the metro infrastructure, as successors to the Highways Agency.

Should the presence, property, and protection interfaces of the interfacing transport stakeholders change in future they will require clearly detailed evidence-based data and reasoning for their ownership, rights, and responsibilities for the existing infrastructure, whilst ensuring the safe continued presence and operation of other transport stakeholder infrastructure.

This can arguably only be achieved through standardised approaches to analysis of the interfaces, gathering of key findings for future reference, the verification of the data required, validation of that evidence-based data and reasoning by existing and future stakeholders, and a means for sharing the agreed findings.

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