Population, land use and travel - Transport Policy and Planning in Great Britain - page 25

Across the country the proportion of children in the population varies according
to the socio-economic characteristics of the adult population and differences in local
housing markets. (Families with young children seeking private housing tend to be
'forced out' of pressurised housing areas.) Areas with particularly high proportions
of children include East London, the West Midlands and former industrial towns
in the north of England on either side of the Pennines. Areas with particularly low
proportions of children include Central London (including the Boroughs of Camden
and Wandsworth), Oxford, Cambridge and Edinburgh, plus - for rather different
reasons - Brighton and Bournemouth.
Variations in the proportion of old people derive not from the indigenous
characteristics of local populations but from the effects of migration associated with
rural and coastal areas - both young people moving out and retired people moving
in. As a result there is a concentration of elderly people virtually throughout the
coastal margins of England and their rural hinterland plus almost the whole of Wales,
northern England and Scotland outside their main urbanised areas. By contrast there
is a relatively low and declining proportion of older people within an area of about
40 miles of Central London - a product of youthful in-migration plus the incentive
amongst the elderly to escape (or capitalise upon) a much-inflated housing market.
2.4 Household composition, size and income
The way in which people come together into households of various types and sizes is
also of fundamental importance to transport planning. This is because of the resultant
demand for separate dwellings, because of the income shared between household
members, and because car ownership and many personal activities are organised on
a household basis. The presence of dependent children is also important because of
their distinctive travel requirements. With younger children especially their needs for
supervision and escort place constraints on the economic activity and travel behaviour
of adults within their household.
Most households can be categorised on the basis of whether they contain a single
adult or a couple and whether they have dependent children. Over the last thirty
years there have been pronounced changes in household composition with a larger
proportion of single-person households (18% to 29%) and a smaller proportion of
households with children (50% to 39% - see Figure 2.1). The growing lone-parent
category includes both women (overwhelmingly) who have never married or formed a
similar relationship and former couples who have separated or divorced.
An important consequence of these changes has been a reduction in average size of
households - from 2.9 to 2.4 persons since 1971, continuing a long-term trend. Falling
household size contributes to traffic growth by reducing car occupancy. (There are
fewer journeys undertaken as a household which involve two or more people.) It also
increases the number of cars which are likely to be owned per adult, thereby increasing
car availability and car use.
Falling household size also means that a larger number of dwellings and potentially
a larger area of development is needed to house a given population. Coupled with the
growing demand for amenity and space which comes with higher incomes (including
the ability to store and use cars) this has contributed to the reduced population density
of built-up areas. In fact, rather paradoxically, the growing tendency for people to 'live
apart' can add to the demand for housing space to enable others to come and stay from
time to time. This can arise with parents and their grown-up children, with divorced