Environmental Engineering Reference
In-Depth Information
Unsustainable
Mobility
Sustainability impact
•
CO
2
Local environment
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Accessibility
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Safety
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Economy
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Policy pathway
Unsustainability
Sustainable
Mobility
Sustainability
2013
Time (2030)
Figure 2.13
Scenario analysis and backcasting
Source
: Hickman et al., 2009a; based on Organisation for Economic Co-operation and Development, 2000.
A common approach has been used in these studies to examine the possibilities of moving
towards a sustainable transport system. The Business as Usual (BAU) projection forms the
starting point as it reflects the trends, and this is taken as the upper limit for CO2 emissions
(and other indicators of sustainable transport) in the future (
Figure 2.13
). A new image of the
future is described, and often targets are used to quantify the level of reduction required in
CO2 emissions or changes in other indicators. A combination of policy measures can be used
and implemented over the intervening time period to help reach the new image. The present
trends are perceived as important only in view of providing a comparator for an agreed future.
The future change trend is a 'choice' for decision-makers rather than something to react to.
Hence this is a fundamentally different approach to forecasting.
Participatory backcasting approaches have recently become been more frequently used, as
involvement with key stakeholders - perhaps (ideally) even the public - mean that the
acceptability of policy proposals is likely to be enhanced (Robinson et al., 2011; Quist et al.,
2011). There are some concerns that participants can be overwhelmed by the complexity of
the choices they are being asked to make, and of course there is a persistent problem in that
only certain sectors of the community tend to get involved in the policy-making process. Often
city authorities like to closely 'manage' their strategy development processes, and equally the
participation process is carefully handled. This can be viewed as a little untransparent or
undemocratic, but generally is done for resource reasons or in an attempt to reduce the risk
of some projects being hijacked or disrupted by particular interest groups - which in themselves
have little electoral validity. However, in the main, the participative approach is perceived as
an extremely positive feature, allowing stakeholders to express their views as to what futures
might be plausible and desirable, and to get their engagement. This should mean that
implementation is more likely and that there will be support for the measures being introduced,
meaning that outcomes match more closely with intentions.
