Background to the Study
For the past half century the development of the City of Cambridge and
surrounding areas has been severely constrained. The Holford Report of 1950 proposed to
limit the development of the City and surrounding villages. It was recommended
that Cambridge should be limited to 100,000 people. This figure was just about
maintained (108,000 in 2001) as a result of restricting housing development and
a strong green belt policy. Employment, especially manufacturing, was encouraged
to locate or relocate elsewhere in the region.
By 1969 the constraints on employment growth were relaxed following the Mott
Report (1969) that allowed science and university based industries to be located
in the city. This opened the way for the Trinity Science Park and similar
employment clusters, which led to the birth of the Cambridge Phenomenon: there
was a surge of growth of high-tech firms and associated services, employing over
23,000 people. Today, this forms the backbone of the Sub-region’s successful
knowledge based economy.
The contradictory nature of the policies that allowed employment to grow but
constrained the growth of housing has had serious consequences: house prices
have risen substantially. It has been necessary for increasing numbers of people
who work in Cambridge to live beyond the green belt, where cheaper housing more
than offsets the cost of travel into Cambridge. Medium and lower income groups
have been displaced because they can no longer afford property prices in
Cambridge unless protected by social housing.
The population growth in
surrounding villages and market towns has been amongst the highest in the
country. As a result there is a daily influx of workers from outside the City:
this outnumbers the resident workers. Traffic congestion has grown as a result
of more people commuting by car, causing delays, accidents and pollution: their
dispersed origins mean that public transport is unviable for many of these
The continued success of the Cambridge Sub-region in now under threat.
Segal Quince Wickstead have reported that difficulties in recruitment and
shortages of available premises are the major threats to future economic growth
in the Sub-region. Recruitment is not helped by increased housing and transport
costs faced by incomers.
In order to maintain and improve the economic opportunities for Cambridge as
well as increasing the social equity of the area while protecting the
environment, the Regional Planning Guidance advocated a change in the policies,
alleviating the constraints on the development of the Cambridge Sub-region. New
housing should be located where the jobs are: in the City, and subject to a
review of the green belt, by extending the city. New housing, beyond green belt,
should be located in a new settlement and in the market towns and large
villages. The recommendations of the Regional Planning Guidance have been taken
further in the Revision of the Structure Plan of Cambridgeshire and
The removal of the 50 year constraints on the size of Cambridge should
increase the population of the built up area of Cambridge by one third from 1999
to 2016. Due to the increase of households and employment, the size of the urban
area will expand into the green belt with more people travelling within the
built up area.
The Base Case assumes the full implementation of the land use policies in the
Structure Plan 2003 and the committed transport improvements. It represents the
most likely land use scenario to become reality. The options represent the Base
Case plus further transport measures. Each show what could be achieved by
focusing entirely on a single transport instrument. These include non-motorised
modes of transport (cycling and walking), public transport, road building (in
the form of an orbital highway), and demand management (represented by
congestion charging). This aims to show what each approach can achieve
independently. There is also a Combined Option that examines how all four of the
options would work together.
The options are broadly consistent with the transport policies in the
Structure Plan, which promote cycling, walking and high quality public
transport, and recognise the need to cater for orbital movements, and provide
Following the first Cambridge Futures (1999) study, the same computer
simulation models (MENTOR/SATURN) have been used for forecasting and assessing
the likely outcomes of alternative options. These models have been used by
Cambridgeshire County Council to test the Structure Plan policies. This
represents the Base Case against which this study compares the options.
Cambridge Futures has added transport elements to this base simulation model
to represent each of the options. As illustrated in the figure above, the models
simulate the working of two inter-related markets: the land market and the
The year 2001 constitutes the base year for comparisons between future
scenarios and existing conditions; the model has then been run at 5 year periods
(i.e. 2006, 2911, 2016 and 2021). This base run represents the implementation of
the Cambridgeshire Structure Plan policies and provides the bench mark against
which the other options have been compared, with transport assessment for years
20901 and 2016. The majority of the outputs are illustrated for the year 2016 –
the final year of the Structure Plan.
The assessment of the options is performed in two ways: feasibility and
sustainability. Feasibility assessment tries to determine to what extent the
options are viable, not only technically but economically. It uses cost benefit
analysis, as recommended by the Treasury for public funding of infrastructural
projects (HM Treasury, 2003), to compare the capital costs of implementing the
options with the benefits generated by the options. The benefits, measured in
monetary terms, are calculated for users of the transport system, to estimate
the rate of return on the investment. There are two rates: social and private.
The social rate includes all valued benefits to society, while the private rate
includes only the benefits accruing to the investor in the transport system.
From a sustainability point of view, the options are assessed in terms of:
- Economic efficiency: this considers the economic impact of the option
measured by changes in prices, for consumers (households) and producers (mainly
exporters). This form of appraisal is more comprehensive than the standard
cost-benefit analysis used in transport assessment (as calculated in the
feasibility assessment above), as it not only measures the benefits to transport
users, but to the economy as a whole.
- Social equity: this considers the distributional impact of the options –
the cost and benefits for different socio economic groups. It also considers the
spatial segregation of socio economic groups.
- Environmental impact. This uses energy consumption as a measure of the
impact of the global environment. Lower fuel consumption represents less use of unrenewable energy and lower carbon emissions, which are thought to contribute
to climate change. The SATURN traffic model produces estimates of overall fuel
consumption by traffic for the Sub-region. This partly depends on total distance
travelled by also on the amount of traffic congestion. Engines are less
efficient when accelerating and decelerating.
Local air pollution is also related to the amount of traffic and is make worse
by congestion. Local environmental effects have been assessed on the basis of
professional judgement rather than surveys and calculation. Noise from
vehicles is related to a number of factors, particularly the volume of
traffic, distance of properties. Other significant local effects include
visual intrusion on the landscape, and the effect on the townscape.
The comparison of the options includes an Appraisal Summary Table that
compares the options against the Base Case using the impacts recommended in the
Guidance for Multi-Modal Studies.