Role of Transport in Urban Growth
Transport is the underlying force in the location, growth, rank-size and functional differentiation of cities. Adequate, cheap and efficient passenger transport facilities are essential requirement of urban life. Cities develop at foci or break of transportation points. They are the nodes of route systems and their importance closely reflects the degree to which they possess the property, which is called nodality.
Well-organised, inexpensive and efficient transport facilities are of the first importance in the economic and social life of our cities and towns. Thus, transportation, both intercity and intra city, is of prime concern of both urban and transport geographers. With the growing urbanisation and rapid growth of transportation it is necessary not only to examine the present pattern of transport but also their problems as well, and suggestions should be given to the policy makers for the better planning of urban transportation system.
During the last century, there has been a rapid growth of urbanisation, resulting in the emergence of million-plus cities. The number of such cities is constantly increasing not only in North America and Europe, but in other parts of the world also. Transport developments were one of the major factors in this growth. The urban growth was accompanied by three important changes in the structure of the cities.
These are:
(i) The separation of work and residence,
(ii) The drain of resident population from the Central Business District, and
(iii) Areal expansion.
These three trends have been made possible by developments in transport. But since these took place in the following well-marked stages, it’s possible to trace their consequences in the structure of the existing urban sub-region.
The changes, well traced in developed countries, are:
(1) The walk to work
(2) The steam railway
(3) The electric train
(4) The motor-bus/electric railway
(5) The post-war suburb
(6) The central business district (CBD)
(7) Industrial areas
(8) The inner suburbs
(9) Medium-density outer suburbs
(10) Low-density outer suburbs
The above mentioned changes in urban areas have resulted into rapid diversifying and intensifying circulation patterns created by journeys to work, to school, for shopping and for recreation. Thus, transport planning and traffic management become prime concern both for town and transport planners.
Travel is necessary to engage in spatially dispersed activities such as work, shopping, visits to friends, etc. In economic terms, travel is an intermediate good, because demand for travel is derived from the demand for other spatially separated goods and services. Thus, one travels in order to engage in work or to do shopping or see a film. Apart from sightseeing and some types of holiday, rarely do people travel simply for the sheer pleasure of the trip.
Like other goods and services, travel has a cost. When an individual makes a trip, he or she values the destination activity sufficiently to incur the trip cost. The cost of travel usually has two components, time and money. Time spent travelling is time not spent doing other things, hence those who value their time highly will be willing to spend more money in order to save time by using a faster mode. For example, business travellers may use air travel or high-speed trains to economise on time spent travelling from one engagement to another, while retirees and university students – for different reasons – are among those who are quite willing to use cheaper and slower buses and local trains.
The urban personal movement is controlled by the principle of distance decay, whereby we attempt to minimise the cost or inconvenience of travel for a given purpose. Another principle is the conditioning of individual travel behaviour by personal circumstances which dictate the need and ability to engage in particular activities. Daniels and Warnes (1980) has developed a hypothetical scheme of movements,
Urban travel pattern is mostly controlled by ‘travel demand’. Travel demand can be examined at the level of individuals or households or at the level of population segments. For this, models have been developed by Chapin (1975) and Hagerstrand (1970). Chapin (1974) conceptualises activity patterns as an outcome of demand and supply, demand being the motivation to take an action, and supply being the opportunity to do so, as illustrated in Figure 5.1. Motivation or desire to act depends on the person’s household role and individual characteristics. Opportunity depends on the availability of resources required to act, and on the perceived value on the act.
Hagerstrand’s (1970) work focuses on the interplay of space and time, since activity locations are distributed in space and time, time resources are required in order both to access locations as well as to participate in the activity itself.
Hagerstrand identified three categories of time and space constraints that affect activity opportunities:
1. Capability constraints describe the limits of the physical system, the transportation technology available and the fact that one can only be in one place at a given time.
2. Coupling constraints describe the schedule dependences of activities, such as the hours of operation of stores, or an individual’s work schedule.
3. Authority constraints describe the legal, social or political limitations placed on access, such as the age requirement for a driver’s license.