Notes on Transport and Land-use (adapted from Lectures by Suman Maitra, Lecturer, URP, BUET) Table 2: Theoretically expected impacts of land use

Notes on Transport and Land-use (adapted from Lectures by Suman Maitra, Lecturer, URP, BUET) Table 2: Theoretically expected impacts of land use

Table 3: Theoretically expected impacts of transport

Table 2 illustrates the impact of land use policies on transport patterns from a theoretical point of view. The impact of high residential density in reducing average trip length is likely to be minimal in the absence of travel cost increases, whereas a high density of employment is positively correlated with average trip length. Attractive neighbourhood facilities can be seen as a 'pull' factor for reducing trip length. Since more peripheral locations usually have longer trips, trip length can be expected to be negatively correlated with city size. With regard to trip frequency little or no impact is to be expected from land use policies according to Zahavi's theory of fixed travel budgets. Residential and employment density as well as large agglomeration size and good public transport accessibility of a location tend to be positively correlated with the modal share of public transport, while neighbourhood design and a mixture of workplaces and residences with shorter trips are likely to have a positive impact on the share of cycling and walking. Table 3 illustrates the impact of transport policies on land use and the impact of transport policies on transport patterns. The latter impacts are included because they tend to be much stronger than those of land use on transport or transport on land use. The impact of transport on land use is mediated by a change in the accessibility of a location. Higher accessibility increases the attractiveness of a location for all types of land uses thus influencing the direction of new urban development. If, however, accessibility in an entire city is increased, it will result in a more dispersed settlement structure. The impacts of transport policies on transport patterns are clearer and stronger compared to the interplay of land use and transport. While travel cost and travel time have a negative impact on both trip length and trip frequency, accessibility has a positive impact on trip length and frequency. Mode choice is dependent upon the relative attractiveness of a mode compared to all other modes. The fastest and cheapest mode is likely to have the highest modal share. In general, the theoretical considerations support the conclusion that the impact of 'pull' measures, i.e. land use measures, is much weaker than the impact of 'push' measures, i.e. increases in travel time, travel cost etc. 3.7 History of cities in transport-land use terms People throughout urban history have shown one characteristic that has shaped the nature of our cities: they do not like to travel more than half an hour to major urban destinations. This has caused three types of cities to develop as transport technologies have evolved towards greater speed and freedom.

3.7.1 The Walking City The traditional walking city which developed around 10 000 years ago and still exists today in some places; it is characterized by high density (100-200 people per ha), mixed land use, joined together by narrow streets in an organic form that fits the landscape. In walking cities all destinations can be reached on foot in half an hour and thus these cities are rarely more than 5 km across. Many cities today have parts which either retain historical walking characteristics, or the municipal authorities have purposely built new sections at a walking scale, eg. the medieval core areas of many European cities, new suburban centres along Stockholm's rail system or new district centres such as Arabella Park (Bogenhausen District Centre) in Munich. Much larger parts of Third World cities retain their highdensity, mixed land use, walking characteristics. The central parts of all US and Australian cities were once walking cities, but this characteristic has largely disappeared now: a few historic precincts retain this old form such as the Rocks in Sydney, the West End of Fremantle, and Society Hill in Philadelphia or the North End in Boston. For some who live in newer high-density precincts in central parts of New York, San Francisco, Melbourne or Sydney, it is possible to reach a majority of destinations by walking, but these are rare in US or Australian cities. 3.7.2 The Transit City In the latter part of the 19th century cities pushed increasingly outwards as the train and tram allowed faster travel to occur (Figure 2). The trains generally created sub-centres at railway stations that were small 'cities' with walking scale characteristics. Trams, on the other hand, created linear development that followed the routes in corridors or 'main streets'. In both cases medium-density, mixed-use areas were formed at the rail nodes and along the tram routes. The city could now spread 20-30 km based on these technologies and where the rail lines met at the city centre very intense activity resulted, and the central area became a dominant focus for the city. The overall density of transit cities reduced to between 50 and 100 people per ha. Most US and Australian cities were formed by the train and tram era and retain characteristics from this period. Melbourne and Philadelphia retain their tram-based linear developments in the inner suburbs, and even though the trams were removed in other cities the basic form can still be seen, such as in Los Angeles, Melbourne or Sydney. 5 Railway station sub-centres are still very clear in most US and Australian cities, and both tram-based 'main streets' and high-density station nodes are very prevalent in a city such as Toronto (see case study below). European cities have tended to retain their transitoriented form, though in recent decades they have begun to disperse around their main corridors based on automobile travel.

Figure 2: The transit city. (1850-1940 dominant city form in industrial world.) 3.7.3 The Automobile City Beginning before the Second World War but really accelerating after it, the automobile progressively became the transport technology that shaped the city. Together with the bus it made it possible to develop in any direction, first filling in between the train lines and then going out as far as 50 km (Figure 3). Low-density housing became more feasible, and as a reaction to the industrial city, town planning began separating functions by zoning. This also increased journey distances but again could be managed due to the flexible and fast transport afforded by cars. The city began to decentralize and disperse. The auto city reduced in density to between 10 and 20 people per ha. Australian and North American cities have grown most of all in the automobile era. Cities such as Canberra and Phoenix have grown almost exclusively in this era; others like Denver, Houston and Perth are mostly post-1940s cities. Now, after 50 years of such automobile based growth, such cities have spread almost to the limits of comfortable car commuting. Their automobile-based, low-density suburbs have become a normal living environment for their citizens who largely have known no other style of city despite its relative novelty in urban history. But new suburbs beyond 40-50 km from the city centre have an extra dimension of isolation from traditional urban functions. And the level of automobile-

based problems in such cities is growing rapidly, leading to many questions that lie behind this special issue of Land Use Policy. Cities in the Third World have also grown in this post-1940s period but have not developed in this pattern. In general they have a more walking and transit oriented urban form, though in cities such as Kuala Lumpur and Bangkok large 'footloose' residential areas based predominantly on car access have been spreading rapidly across the landscape in the 1980s and 1990s. European cities vary between cities like Stockholm with its strongly maintained commitment to transit-based corridor development and subcentres, to cities like Oslo, Frankfurt and many in the UK where car-based suburbs and scattered 'villages' on the fringe have been allowed to proliferate. Most cities today contain some elements of all three city types; as the data on New York, San Francisco and Melbourne reveal, there are considerable variations in car use with density across cities. The variations in public transport for the journey to work in Melbourne, which again indicates the close link between land use and transport. The same pattern is seen in all Australian cities, where income is highest in inner and middle areas (the opposite of US cities, where income is often the primary variable used to explain the variations in transport). Figure 3: The automobile city. (1940-Present, US and Australian cities mostly.)