Solario wrote:
wrote:
wrote:
burkey wrote:
However, the Croxley Rail Link, a plan to extend the Metropolitan Line
to Watford Junction, has yet to meet the appropriate conditions for
approval.
The DfT has said that it anticipates the scheme will be approved within
the next ten years but that it will need close scrutiny in terms of
value for money. It would take at least £50m to realise the proposed
extension.
(snip)
If our beloved politicians cannot deal with a simple project like the
Croxley Link,
As I understand it, they have *dealt* with it, by declining it as it
has yet to meet the appropriate conditions for approval.
that gives enormous benefits for little outlay,
Define 'enormous' and 'little' (£50m), and compare and contrast with
other projects.
Nothing is inexpensive these days. I refer you to Mr. Ford's
references to "Boiling Frogs".
All such projects are assessed for costs and benefits. Any idea what
the CBA is for this project and why it doesn't meet the criteria?
No, and I don't know the criterea these guys utilize. How does one
quantify the benefits of reconnecting all Metroland to the main line?
One of the main criteria used is probably time savings, converted to a
monetary value. This will factor in time savings for existing travellers
as well as benefits for new travellers and disbenefits for those who
will no longer travel or will switch to less favourable modes.
Other monetised benefits/disbenefits will be:
- changes in road congestion
- changes in fare revenues (for both LUL and local buses)
- changes in operating costs
- changes in indirect tax revenue (usually a loss if car drivers switch
to the new public transport)
- changes in number of accidents (usually important because it can have
a large monetary magnitude)
- changes in noise levels
These will be measured against the capital costs of infrastructure and
rolling stock as distributed over a set period, something like 50 years
from opening. The output is the BCR (benefit-cost ratio) or NPV (net
present value) figure, the former measuring how good value for money the
scheme is, and the latter measuring the magnitude of the return on
investment.
However, there is an additional part of the assessment which deals with
non-monetised benefits and disbenefits - to do with various
environmental and social factors. Examples are impact on
landscape/townscape, biodiversity, historic resources, water, journey
ambience, greenhouse gas emissions, severance, access to transport, ease
of modal interchange, and compatibility with land-use policy and other
policies. Most of these are given a score (and are thus more subjective
than the monetised benefits) except for greenhouse gas emissions which
are quantified as CO2-equivalent tonnes.
So although the first-glance BCR or NPV figure may not "sell" a project,
the non-monetised factors will affect how the monetised value is
treated. An example I've been told is that building a new airport in
Hyde Park would have a big positive BCR (huge journey time savings!),
but obviously it would never happen because it would receive a rather
less impressive score for the non-monetised factors.
Additionally, monetary values are usually calculated for several
different options for a project, including a "do-nothing" scenario and
some soft measures, and the values for the preferred option are compared
against this (e.g. if the do-nothing scenario has a large negative NPV,
e.g. -£50m, then the preferred project may be favourable even if its NPV
is quite small, e.g. +£5m).
Of course, I don't know how this applies to the Croxley Link unless
someone can produce the summary table which such assessments are
required to produce.
(snip rest)
--
Dave Arquati
Imperial College, SW7
www.alwaystouchout.com - Transport projects in London