Transport and economic development - Transport Policy and Planning in Great Britain - page 9

1.3 Transport supply
The quality of transport supply acts to facilitate or constrain the growth in travel. By
quality we mean not merely the speed and safety offered by individual sections of route
or the services operating over them but their configuration as a network relative to
the patterns of demand generated by land use activity in an area. By reducing travel
time the same connections can be made at less cost or better connections made for
the same cost.
The patterning of accessibility created by transport networks influences travel
choices and hence the resulting patterns of demand. It also has an effect on decisions
by firms and households over where to locate and hence, over time, contributes to
the evolution of settlements and, more locally, to patterns of land use and built form.
The development of the nation's highway network to accommodate the motor
vehicle differs from the earlier development of the railway network in that ownership
of the infrastructure has been separate from ownership of the vehicles running on it. In
addition the infrastructure remains predominantly publicly owned whilst the vehicles
are mostly private. The extent to which firms and households can gain advantage
from the vehicles they have acquired has thus depended on public decisions about the
standard of the road network.
The policy issues surrounding this are considered in Part 2. Suffice it to say that
the 1950s represent a landmark in the evolution of transport policy in that official
approval was given to the radical restructuring of the national road network in order
to realise the capabilities of the motor vehicle. In a period of just twenty years (from
1960 to 1980) a motorway network of almost 1,600 miles was built which had symbolic
as well as functional significance in marking a transition to a new era. In the 25 years
since only 600 miles has been added to it. Instead, during this time, the length of dual
carriageway 'A' roads has increased by nearly 2,000 miles (to 4,900 miles).
The current form of Britain's national road network is shown in Figure 1.2. From
this it can be seen that motorways and dual carriageways are concentrated in the more
central and southern parts of England. This reflects the pattern of urbanisation and
hence the density of traffic movements. However it is important to note that these
types of road as well as providing greater physical capacity also make possible higher
traffic speeds. The relative accessibility of parts of the country not served by these types
of road therefore tends to worsen, with potentially deleterious economic consequences.
This explains the long-standing campaigns for dual carriageway improvements to serve
remoter, lightly populated areas - for example the A11 to Norwich, the A30 through
Cornwall or the A1 north of Newcastle.
Even within particular cities and sub-regions the configuration of the main road
network and the standard of its component sections often leaves much to be desired
even after a century of purposeful investment. This is partly because of the inevitable
'lumpiness' of highway schemes and the fact that the network remains in a state of
continuing improvement. (For example if bypasses or dual carriageway sections have
been introduced along some parts of a route then the shortcomings of the unimproved
sections tend to become even more conspicuous.) In some cases highway authorities'
practice of 'leaving the most difficult bit until last' may result in a desired standard
of improvement never being achieved along the length of a route. This could - and
arguably should - have happened with the M3 at Twyford Down near Winchester and
currently threatens to occur at the unimproved section of the A303 trunk road at
Stonehenge.