The following summarises the findings of a recent project. Thanks to
all who contributed to the review stages through this and other e-
mail groups.
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This note describes a study carried out recently by MVA and David
Simmonds Consultancy for the Department of the Environment, Transport
and the Regions, into the land-use impacts of parking restraint,
particularly in city centres. The study involved two literature
reviews - one looking at the empirical evidence relevant to the land-
use impact of parking restraint, and the other looking at relevant
models and previous modelling results. These were followed by an
application of the DSCMOD land-use change indicators model based upon
the outputs of the TRAM transport model.
The review of empirical evidence found that there have been few
studies of the direct impacts of parking restraint, primarily because
there have been few cases in which policies of restraint covering all
types of parking (on- and off-street, private and public) have been
applied on a sustained basis. There does not seem to be any directly
observed long-term evidence showing that restraint of parking in
itself causes problems such as the decline of traditional shopping
centres. However, the balance of the evidence suggests that
significant restraint would have a negative effect on retailing and
other activities, unless counterbalanced by other improvements.
Experience of pedestrianisation indicates that environmental
improvements can more than counterbalance reduced accessibility so as
to make particular parts of centres more attractive and more
successful, though the changes involved may involve complex patterns
of gains and losses.
The review of modelling found that the availability of parking is
generally treated by fairly simple cost and time elements in the
transport components of land-use/transport interaction models. A
range of models capable of responding to such elements is considered,
and available results (from the previous MVA/DSC study within this
programme, and from the ISGLUTI project) are summarised. Extreme
caution needs to be exercised in generalising from these results, but
typical impacts are limited decentralisation of employment with mixed
impacts on household and population distributions. None of the
models considered has explicitly represented parking as a use of land
or of floorspace.
The TRAM+DSCMOD land-use indicators are the results of a simple
static land-use model linked to the TRAM transport model. TRAM was
developed by MVA earlier in the present programme of research, as a
tool for analysis of parking and traffic restraint. (Descriptions of
DSCMOD and of TRAM can be found in Roberts and Simmonds, 1997,
section 4, and in Bates et al, 1997, respectively.) The results of
the Do-Maximum strategy show an insignificant move of households into
the Central Area of the Study Area city (Bristol), and a small
outward move of employment; these are rather more negative for the
Central Area than the previous START+DSCMOD results. The Do-
Something strategy, in contrast, indicates a very slight growth in
Central Area employment. The detailed results show marked
differences within different zones of the Central Area.
The main conclusions drawn are
1 that any major schemes of parking restraint should be
accompanied by careful monitoring and analysis of longer-term
effects, and
2 that further modelling work appears appropriate to identify the
expected effects of such policies and of other associated
measures (for example, to offset the negative impact of parking
restraint by making the centre more attractive in other ways).
Such modelling should move on from static indicators of land-use
impact to the use of dynamic models which can more explicitly
consider the processes of urban change.
References
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Bates, J, A Skinner, G Scholefield and R Bradley (1997): Study of
parking and traffic demand 2: a Traffic Restraint Analysis Model
(TRAM). Traffic Engineering & Control, March 1997, pp 135-141.
Roberts, M and D C Simmonds (1997): A strategic modelling approach
for urban policy development. Traffic Engineering & Control,
July/August 1997, pp 377-384.
Further information
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A paper is being prepared for publication. For further information
on the project summarised above, please contact Ben Still or David
Simmonds at the address below. The project was part of a wider study
of parking and traffic demand; for further information on this,
please contact Denvil Coombe at MVA ([log in to unmask]).
Note
----
The views expressed are those of the consultants (MVA and David
Simmonds Consultancy) and are not necessarily those of the Department
of Environment, Transport and the Regions.
[end]
David Simmonds Consultancy
10 Jesus Lane Cambridge CB5 8BA England
Phone +44(0)1223 316098 Fax +44(0)1223 313893
e-mail [log in to unmask]
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