Strategy Selection and Consistency of Results
57. The 10 Year Plan includes an analysis of the contribution
of each of the elements of the Plan to congestion reduction as
shown in Table 4. The results were derived by comparing the outcome
of the full Plan against the Plan without each of the components
in turn. For example, of the 22 per cent congestion reduction
from the whole plan, 19 per cent could be achieved without any
investment in local transport.
||Reduction in 2010 congestion|
(percentage points of 2000)
|Plan as a whole||22%
Source: Transport 2010: Background Analysis, p32
58. The Department's calculations of the relative contribution
of different policies do not appear to add up to a credible total.
No one element of the Plan seems to provide a large contribution
to the overall congestion reduction target. It is difficult to
understand from the figures presented how the investment figures
for each part of the Plan were arrived at. For example, the impact
on congestion of no investment on the trunk road network, if all
other elements of the Plan were in place, would be an eight per
Such a change would be barely perceptible to road users
and could be further offset by improvements to local transport
schemes that would take further traffic off the strategic road
network. The national average congestion value would still fall
by 3 per cent compared to 2000 levels. This is not to suggest
that no investment in trunk roads is the correct solution. However,
it highlights the weakness of the case made for the investment
package actually put forward. It is normal practice to compare
several possible strategies against the baseline "do minimum"
scenario in order to justify the final strategy that is selected.
This has not been done.
59. Alternative strategies for achieving the goals of the Plan's
must be evaluated, especially when so much prima facie
evidence suggests that there are many very effective instruments
that are hardly mentioned. There is no clear rationale for the
balance of schemes presented in the current Plan. There has been
no analysis of the funding and extra costs or benefits that would
be provided by alternative strategies such as holding motoring
costs constant which, when tested, appears so much more
successful than other initiatives that are in the Plan. In general
it seems to be the case that there is little or no analytical
consideration of a wide range of policies aimed at reducing traffic
growth, whether by pricing, reallocation of road space, pedestrianisation,
more active landuse control, traffic calming, education
or tax incentives. These policies are all complex and have a different
balance of advantage and disadvantage, but they are clearly wellthought
of by Government in the right context, as proved by the wide range
of guidance notes and speeches from DTLR. The Department has
failed to provide any meaningful justification for the collection
of schemes it has chosen for the Plan. The costs and benefits
of different strategies must be assessed in the revised Plan.
60. A number of other inconsistencies in the Plan's model were
highlighted in the evidence. The Plan will reduce the expected
traffic growth levels in urban areas by about 5 per cent.
The Institute of Logistics and Transport estimates that a 5 per
cent fall in traffic levels is equivalent to a reduction of 9
billion vehicle kilometres, or to about 10 billion person kilometres.
It estimates that "doubling the use of light rail would account
for 0.5 billion of this and a 10% increase in bus travel, a further
2.7 billion passenger kilometres. This leaves 6.8 billion passenger
kilometres of the fall in car travel unaccounted for. The worry
is that this represents car users who have abandoned central urban
areas and are continuing to travel by car, but to suburban or
61. There are considerable discrepancies in the importance attached
to congestion charging schemes between the Government,
and the Commission for Integrated Transport.
We believe that it is likely that local models such as that used
by Bristol City Council will provide a better understanding of
the impacts of different policies at a local level. The Committee
has been unable to investigate these contradictions but notes
that they exist and that resolving them is essential to understanding
what the Plan will achieve.
62. It is unclear from the modelling results presented by the
Department whether the model is consistent. It is also unclear
whether the model is suitable for the broad analysis of transport
trends for road and rail from a national to a local level. The
Committee notes that a new version of the model is being developed
to assist in the review of the Plan. It is important that the
results from the new model do not further confuse the picture.
The Department should undertake any new analysis for the review
of the Plan with both the current and the new model, and present
the results in parallel. It must be transparent whether changes
to the expected outcomes of the 10 Year Plan are the result of
changes to the model or from changes to the inputs and assumptions.
The Department must also allow independent access to the new
model, in the same way as the Treasury allows such access to its
model of the economy.