Environmental Engineering Reference
In-Depth Information
and city planning! In the absence of this, scenario analysis provides a very useful framework
for considering transport futures within the context of uncertainty. It allows us to consider
possibilities beyond the BAU trajectory, and it is exactly this that is required in the current
transport planning domain, where many important issues, including climate change, demand
a different type of response to that which comes from more conventional transport planning
analysis.
In the urban planning world, Hall (1980) takes us through some
Great Planning Disasters
,
where many high profile and 'problematic' major projects appear to have been initiated on
the basis of planning that was later found inadequate and perhaps even misleading. These
include: the London Ringways (proposed urban motorways in London, abandoned in the
1970s), which were planned on the basis of estimates of population, economic activity and
car ownership which were later seen as over-estimates; the Bay Area Rapid Transit (BART)
system in San Francisco, based on travel forecasts that were hugely over optimistic; Concorde
(a supersonic aircraft), developed on the basis of inflated estimates of the demand for supersonic
travel; and the Sydney Opera House, with multiple design and cost overrun problems. Many
of these projects, and many others since, were started on the basis of cost estimates that were
soon exceeded, some by a very large amount. There are various factors behind these difficult
development stories (Friend and Jessop, 1969; Hall, 1980), including:
•
Uncertainty about the planning environment (i.e. everything outside the immediate decision-
making system). Planners in practice cannot easily predict the mass behaviour of people
in society, such as propensity to have children, move about, or demand different goods
and services.
•
Uncertainty about decisions in related decision areas, such as those related to areas beyond
the immediate problem, involving wider decision-makers in groups or organisations with
their own discretion.
•
Uncertainty about value judgments, including decisions where the final judgment involves
questions of value, with different weightings according to group, all of which may change
over time.
These issues have more recently been taken up in considering the planning and delivery
of major infrastructure projects (Flyvbjerg et al., 2003; Priemus et al., 2008; Dimitriou et al.,
2012), with concerns over the effectiveness of decision-making, the methodology applied in
forecasting (often complexity and uncertainty is difficult or impossible to model); poor data
availability; discontinuous behaviour (either inelastic; or very elastic, with sudden changes
due to external factors which often are not modelled); political activities and even appraisal
bias.
All of these issues have an important bearing on transport and city planning over the long
term, and scenario analysis can assist in dealing with problems of uncertainty or difficulties
in the accuracy of modelling. The current level of global motorisation, its impact on the city,
life and the associated problems of climate change and oil scarcity, together with the
intractability of changing travel behaviours, are similar examples of 'wicked problems' (Rittel
and Webber, 1973) - and manifest themselves at the grand scale. There is certainly no well-
prescribed solution to these issues, and to a large extent the current policy framework can
only deal with 'tame problems'. It can work with emerging trends, changing their direction
to only a minor degree. This is a major problem: we have very few examples of policy that
changes trends to a radical degree, yet the strategic climate change agenda demands some
major bending of the current trends.
