Seven ways to expand a city
The University of Cambridge department of architecture has carried out a unique collaboration with businesses and local government to explore the future potential for the city and the surrounding area.
The collaborative grouping, called Cambridge Futures, has looked at seven ways in which the city could develop and has assessed them in terms of their economic efficiency, their effect on social equity and the resultant environmental quality.
It has used sophisticated computer modelling to determine how changes in regulation of land use and transport, plus direct investment and pricing activity, would affect behaviour in terms of demand for and price of housing and business space, and traffic behaviour and congestion.
The models are the mentor land-use model, and a combination of a multi- modal model of transport and the saturn highway model of the county. These have been combined to produce an integrated picture.
Professor Marcial Echenique of the department of architecture and director of Cambridge Futures, said that the study is unique in the way that it links land-use modelling with 3D animation (a video is available). 'The idea,' he said, 'is that we should explore the opportunities and alternatives. With being independent, we could think the unthinkable.'
This is an interesting and important area to study, because Cambridge is a carefully preserved historic city which, through the excellence of its university, has attracted a lot of high-tech industry. There is a desire to continue encouraging this, without destroying the environment that made the area attractive in the first place, or pricing out all but the richest inhabitants. Pressures are high as this area has one of the highest levels of existing and projected household growth. The study considers seven scenarios:
Option 1: Minimum growth would preserve the City of Cambridge and surrounding South Cambridgeshire. All new dwellings and business floorspace would be allocated to East Cambridgeshire and Huntingdonshire.
Option 2: Densification would put the maximum development in Cambridge city where demand is highest. Higher buildings in a more compact form would be allowed to replace existing low-density development.
Option 3: Necklace development would continue the policy of the last 50 years, with minimum growth in the city and green belt. Growth would be in existing and new villages and in the main market towns.
Option 4: Green swap involves allowing development in selected areas of the green belt, with developers in return providing equivalent or enhanced amenities out of town.
Option 5: Transport links envisages all further development happening within easy access of a public-transport corridor. It would require investment in an enhanced public-transport system and the opening of new stations.
Option 6: Virtual highway proposes a high-capacity electronic communications system to provide instant business and personal communications. It is based on a concept of a multi-media super corridor where audio, computer and visual communication are interconnected. It would involve investing in a high-capacity network and transmission in a form in which wide-band radio waves would be transmitted to users in houses and other buildings.
Option 7: New town would concentrate most of the development in a single location large enough to become an alternative to the City of Cambridge. It would require investment in new transport links to the city.
No solution is ideal. Densification for example scores highly on economic efficiency and social equity but poorly in terms of environmental quality. The virtual highway, in contrast, has the best score on environmental quality, but a poor to indifferent score on economic efficiency and social equity. Transport links is the only solution to offer a reasonable score in all three categories - but is outstanding in none of them. The researchers argue that with no obvious preferred solution, it is essential that the public and decision makers are as well informed as possible.
The 'new town' option under discussion for a long time scored, said Echenique, surprisingly badly. It achieved a rating of only one out of five for economic efficiency and social equity, although it managed four out of five for environmental quality. It pushed the cost of housing in central Cambridge even higher than under the 'minimum growth' option, making it more than three times as costly as under the 'densification' option.
The findings have gone on display in Cambridge. Earliest public reaction favours the Transport Links option, with Green Swap the second most popular. Both the city and the county are due to start amending their structure plans in June, and Echenique has been asked to make a presentation. 'The computer models we have give much more detailed information than is contained in the report,' he said.
Contact Cambridge Futures, 01223 740564.