Geography Reference
In-Depth Information
improvement. Accessibility by public transport
is most easily gauged by scheduled journey
times. The relative status of a number of villages,
for example, can be discerned by comparing
travel times from each to a single regional
centre. It is more realistic, however, to calculate
timings to the nearest intermediate-sized town
(a predictable shopping destination), which also
allows 'travel time hinterlands' to be defined
around each.
It should be emphasised that at the regional
scale, no single measure of accessibility is adequate
by itself. Combinations of methods under the last
two sub-categories are best. See, for example,
Nutley (1979; 1984) on the Scottish Highlands
and ruralWales.
However, in order to identify precisely where
problems of accessibility are occurring (e.g.
population sub-group A in village B has
inadequate access to facility C in town D), and
hence aid policy solutions (e.g. re-timing a bus
service), it is necessary to focus on small case study
areas. Points of demand are specific settlements
such as villages. Destinations (supply points) are
also more specific: hence, instead of 'shopping' or
'leisure', access is postulated to different shop types
and leisure outlets at different levels in the urban
hierarchy, not just the nearest. It is also very
important to disaggregate the population into
sub-groups likely to have different travel needs,
such as working people, housewives, the elderly,
school-children, etc. Needs, in terms of destination
facilities and desirable frequency of access, are
defined by setting normative standards (for other
needs measures, see Bird (1981) and Moyes
(1989)).
Ensuring adequate accessibility is an exercise in
time-space coordination, not merely making
connections over physical space but also taking
account of available time. Useful techniques are
derived from 'time geography', developed by
Swedish geographers in the 1970s. All individuals
have a 'time budget' such that after domestic
duties, work or school, a certain time is left for
travel; time in transit is deducted from this, and
that remaining must allow sufficient time at the
destination and must accord with the facility's
opening hours. Standards are pre-defined by the
analyst and applied uniformly: times available for
travel, maximum walking distance, minimum stay
time at destination, and frequency (days per week)
that the facility is 'needed'. Car users and public
transport users must be studied separately. For each
village, there is a matrix of social groups versus
needed facilities. In each cell, it is recorded
whether or not that group can successfully achieve
access to that facility under the defined conditions.
Accessibility is the percentage of desirable social
group/facility contacts that can be satisfied by the
prevailing transport system.
Such methodologies have been used by
Moseley et al . (1977) in Norfolk, England, and by
Nutley (1983) in rural Wales (Box 35.3). They
Local accessibility and the time-space
approach
To be more relevant to the experience of people
at grassroots level, traditional techniques need
considerable improvement. First, a much higher
resolution of study is required, so that localised
variations can be detected. Second, it must be
possible to distinguish access for specific journey
purposes. Third, a time dimension must be
included, so that it can be checked that transport
arrives at the destination at times suitable for the
desired activities. In the first instance, such an
approach aims to assess public transport for that
section of the population dependent on this. If
one is dealing with a large area, it must be divided
into small units such as parishes or wards.
Transport services available to these units are
then examined to see whether they connect with
suitable towns at times and frequencies
appropriate for work, shopping, leisure, etc.
Localities with/ without the requisite access can
then be mapped. Furthermore, by using a points-
scoring system, accessibility for different journey
purposes can be summed to produce a
'composite access index'. Ideally, the latter should
be qualified by some measure of car ownership.
For applications, see Nutley (1980) on rural Wales
(Box 35.2) and Jordan and Nutley (1993) on
Northern Ireland.
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