Future scenarios and strategic choices - Transport Policy and Planning in Great Britain - page 416

• continuation of present trends in migration
• real reductions in the cost of travel (especially car travel).

Despite the volume of road-building assumed, congestion on the highway network
(measured as delay relative to free-flow speed) would increase by 30%. Thirteen per
cent of traffic would experience very congested conditions by 2025 (compared with 8%
in 2003). One-third of London traffic and one-fifth of traffic in other urban areas would
experience these conditions. With forecast increases in the length of commuting and
business trips, congestion is also expected to spread more widely across the strategic
road network, especially in the main inter-urban corridors. Without further action the
cost to the economy of lost travel time would be at least £24bn a year, half this being
borne by business travellers and freight users. Notwithstanding the increases in traffic
volume and congestion, improvements in vehicle efficiency would result in a net 4%
reduction in CO 2 emissions from road transport.
Eddington noted that the parts of the network already under pressure were the
places which were likely to see the fastest growing demands. Without further action
continued economic success is likely to exacerbate problems at these locations under a
range of plausible scenarios. By contrast a system of national road user charging would
enable these problems to be addressed and would also reduce the case for inter-urban
road-building beyond 2015 by some 80% (i.e. to 500-850 lane km in the period to
2025). Without road pricing however there would be an economic case for increasing
the rate of road capacity enhancement by over 50% compared with the baseline case.
Eddington's support of road user charging forms part of a general argument
advocating the 'better use' of existing networks (Table 24.3):

Better use options have the potential to contribute significantly to GDP and can
have good environmental impacts. Therefore these should always be the first option
considered. In some circumstances however making better use can only go so far,
prompting the need to consider the costs and benefits of additional infrastructure.
(Eddington Main report para 4.1)

Table 24.3 Better use measures (source: adapted from Eddington Main Report Figure 2.1)

Measure

Impact on the network

Supply-side
measures

Traffic
management

Active management of traffic throughput to increase flow

Incident
management

Improved traffic throughput by making the network more
resilient to disruptions

Reallocation of
capacity

Reallocate infrastructure capacity between modes to
increase overall benefit and/or support wider strategy

Maintenance Regular maintenance regimes prevent future disruption

and extend asset life

Demand-side
measures

Pricing Better pricing can spread demand and, if well targeted,

allow the network to be used more effectively

Soft measures Increasing public awareness of travel options and reducing

demand for car travel by taking small practical steps to
making alternatives 'easier'

Regulation Improving transport performance (including impact on

externalities) by specifying minimum service levels