Project appraisal - Transport Policy and Planning in Great Britain - page 346

The distinctive feature of NATA was and remains the structuring of information
in terms of the Government's five main objectives, viz environment, safety, economy,
accessibility and integration. Different aspects of performance are assessed for a series
of 'sub-objectives' under these headings - so that for example the main objective 'to
improve safety' is subdivided into 'to reduce accidents' and 'to improve security' (Table
11.1 previously).
The conclusions are brought together in a single-page 'Appraisal Summary Table'
(AST) with each row of the table reporting the impact of the proposal on each sub-
objective (TAG unit 2.7.2). The table includes a column for a brief textual description
of qualitative impact and a column for quantitative measurement. Depending on the
nature of the attribute a final column summarises the assessment in terms of either an
impact measurement or score or (where the impact can be assigned a monetary value)
a measure of net cost or benefit.
To the uninitiated, there are number of oddities in the appraisal framework, both
in the definition of sub-objectives and in the precise way these are interpreted and
measured. The explanation of these lies in the compromise made between a desire to
present impacts comprehensively and impartially (so that bias is not introduced in the
way information is presented to decision-takers), yet at the same time respecting the
structure set by the overarching objectives. For example 'Safety' is singled out even
though it represents a mix of economic concerns (the costs of damage, healthcare,
loss of productive capability etc. associated with accidents) and personal or social
concerns - e.g. 'suffering' (which is actually assigned a monetary value) and anxiety
over personal security.
The framework's concern for impartiality is reflected in the fact that each sub-
objective is presented as of equivalent status. No attempt is made to pre-judge the
relative importance of sub-objectives by aggregating individual impacts in any way
so as to try and present an overall assessment of the benefit or worth of a scheme.
(An important proviso to this surrounds the parallel exercise in determining 'value for
money' which we consider below.) However any particular impact is classified, care is
taken to ensure that it only appears once in the table (i.e. to avoid 'double-counting').
The precise specification of each sub-objective and the detailed information to be
supplied in worksheets accompanying the AST is explained in TAG units 3.3-3.7.
Assessment of the 'Land Use Policy' and 'Other Government Policy' sub-objectives
under the 'Integration' heading are different from those in the remainder of the table.
They are not concerned with the measurement of substantive impacts and whether
these are intrinsically good or bad but rather whether they contribute to or conflict
with Government policy in other sectors. (Impacts on individual policies are recorded
in accompanying worksheets.) These are aggregated to offer an overall assessment
summarised simply as 'neutral', 'beneficial' or 'adverse' in the AST.
Because of the close interaction between transport and land use it can be questioned
whether a scheme which conflicts significantly with spatial policies in its area ought to
be under consideration at all! This highlights the fact that the relationship with spatial
policies should ideally be explored in the genesis of schemes through regional strategies
(Chapter 18). It will in any case remain to be tested when planning permission is
sought (22.3).