Which mode of transportation has had the greatest impact on the location of major cities?

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Highlights

•

Urban transport policy develops over time, as cities evolve and priorities change.

Early focus on major investment for cars, in roads and parking

Advanced cities promote sustainable modes & high quality streets: car use declines.

There are ‘legacy’ issues in modelling and appraisal, linking back to car policies.

Need to pay more attention to the wider socio-technical context of travel.

Abstract

Urban mobility in Western countries has evolved substantially over the past fifty years, from an early interest in catering for growing car ownership and use through major road expansion, to the current emphasis on reducing car use and cutting back on road provision, encouraging sustainable travel and promoting liveable cities with a high quality of life. This can be observed in the changing patterns of car use in many European cities over time [i.e. a rapid increase followed by stabilisation and now decline]. This evolution can be related to changes in the transport policy paradigm, which has been heavily influenced by the involvement of an increasing range of academic disciplines, many of which have contributed to modifying the supporting data collection, modelling and appraisal methodologies. The paper explores the varying interplay over time between academic/applied research and policy practice, and the methodological legacy left by earlier perspectives on urban mobility. It highlights a recent reinterpretation of mobility provided through taking a 'socio-technical perspective', and speculates on how policy thinking on urban mobility might further evolve over the next forty years.

Keywords

Urban mobility

Car use

Transport policy evolution

Modelling

Appraisal

Socio-technical systems

Copyright © 2014 International Association of Traffic and Safety Sciences. Published by Elsevier Ltd.

1. Transportation Spatial Organization

Two dimensions are used in the spatial structure to emphasize how uncommon homogeneity is. The first is related to spatial differentiation, where characteristics like location, size, and density highlight disparities in how factors like people or resources are distributed. Since different components of the spatial structure, such as metropolitan regions, collect infrastructure and population at varying rates and densities, this differentiation is the result of a cumulative process of spatial accumulation. The second deals with spatial interactions where flows show disparities in origin and destination properties.

The spatial structure is influenced by transportation in addition to favoring economic development. Transport networks have shaped space at various scales throughout history. A diverse range of people and freight flows are produced by the fragmentation of production and consumption, locational specificities of resources, labor, and markets. Spatial organization is strongly tied to the structure of these flows in terms of origin, destination, and routing. A clear illustration of the reciprocity between transportation and its geography is the way in which space both influences and is influenced by transportation. Two points can be used to express this reciprocity:

• Reciprocity between places: This link covers the transport system and the impacts it has on localities. Nodes and links in the transport system, as well as the flows they support, make the spatial organization of this system a key defining feature of the spatial structure. [text shortened] Transportation, by its physicality, shapes the spatial structure. When it comes to urban planning, even if streets aren't the city itself, they still have a significant impact on how it's organized. The same is true of the world's maritime transportation networks, which do not just transport goods across borders but also reflect the global economy's geographical organization.

• Demanding of reciprocity: This connection includes a wide range of activities that are intertwined with transportation on various levels and scales. Since every single activity is predicated on a level of transport demand and mobility, the link they have with transportation is mirrored in their spatial structure. Large manufacturing facilities depend on worldwide freight distribution for both their inputs [parts] and their outputs [products], whereas small retail businesses are constrained by local accessibility to draw their customers [finished goods].

When economies grow more intertwined, transportation plays an increasingly important role in both supporting and influencing those interdependencies. However, the necessity of transportation can be disregarded as interdependencies would be detected while their structural support less so; The impact is being observed while its cause is not. Transportation infrastructures are constrained by a number of reasons, including the physical environment, the quantity of demand, the available capital, and the regulatory environment. The global, regional, and local geographic scales can all be used to analyze the connection between transport and spatial organization.

2. There is a Global Spatial Organization

At the global level, transportation promotes and shapes economic specialization and productivity through international trade. Markets and development prospects are being opened up as a result of transport improvements, but not in the same way. The disparities of the global economy are reflected in its spatial organization and the structure of international transport systems. Trade and interdependence have grown as a result of globalization. Telecommunications, sea transport, and air transport, because of their size of service, support most global flows. Global disparities in growth and accessibility can be explained by looking at the nature and spatial structure of these flows.

• The center and the edges: This basic model posits that the global spatial organization favors a few core places that expand faster than the periphery, with differential growth causing inequalities in development levels. Migration flows, for example, are a good indicator of different levels of economic development, with the majority of migration coming from countries with lower levels of development. In this way, transportation is seen as contributing to social segregation and inequality. As a result, some sectors of the global economy benefit from increased accessibility, while others are sidelined and relegated to a state of dependency. However, this trend can be reversed if international transport costs are dramatically decreased. Export-oriented strategies necessitate effective worldwide freight distribution, as illustrated by the rapid rise of several Pacific Asian nations. As a result, the relationship between the center and the peripheral is fluid, relative, and subject to alter throughout time.

• Poles: Transportation is seen as an articulation component in the global economy, where the flow of passengers and goods is regulated by poles corresponding to a large concentration of transport infrastructures, distribution facilities, and economic activities. A combination of centrifugal and centripetal pressures has promoted the concentration of some activities, while dispersing others, in these areas. Freight distribution relies on networks designed to support its passage and nodes that regulate flow within networks as the backbone of global economics. Networks, particularly those addressing maritime shipping and air transportation, are flexible entities that alter with the ebb and tides of business, while nodes are locations fixed within their area geography.

Depending on their geographic and modal context, global flows are handled by poles referred to as "gateways" or "hubs."

• Gateway: A site that is easily accessible to a vast transportation network. As a result of their strategic placement at intersections of major highways, rivers, or a well-developed port, gateways have accrued a substantial amount of transport infrastructure. A gateway can serve as a point of departure, a final destination, or all three. It has a monopoly on both the entrance and the exit to the territory it covers. So it's a major entry and exit point for a country, continent, or perhaps a whole continent, requiring frequent intermodal transfers.

• Hub: a single location where items are collected, sorted, transshipped, and distributed over a region. The term "Hub and Spoke" refers to a collecting and distribution system that uses a single hub to transport both passengers and freight.

The global spatial arrangement is a priori conditioned by its connection, which is typically representative of a network structure. Nodes and foreland [which is usually connected to the rest of the world by sea and air] and hinterlands make up the bulk of this system [regional connectivity usually by land transport systems]. It is possible for a region to acquire a number of large intermodal assets, such as ports and airports, to strengthen its connectivity through economies of agglomeration and accessibility. They can be considered gateway systems [or areas] when they serve as a point of connection between major circulatory systems and act as an interface. The capacity, performance of their infrastructure, or supply chain management capabilities of gateways operate as bottlenecks in global freight distribution. To gain control over broad market areas, ports and other strategic locations, train transportation began creating gateways in the late nineteenth century. Later, the introduction of air transport facilitated the creation of gateways between global and regional air transport systems.

Services appear to be following a distinct spatial pattern from production. High-level services were concentrated in a few large metropolitan regions, known as world cities, as production moved to lower-cost locations around the world. Cities like New York, London, and Paris are hubs for financial services [banking and insurance], big multinational firms' headquarters, innovation clusters, and nexuses for the arts. Gateways and world cities may not always correspond as locations, underscoring the continued tension between core sites [commercial imperatives] and transport places [distribution imperatives] [distribution imperatives]. New manufacturing clusters and use of intermediary hubs have a direct impact on containerized traffic. Many of the world's largest container ports, including New York, Shanghai, and Tokyo, are not necessarily global cities.

3. Organization of Regional Space

The term "urban system" refers to a grouping of cities that are interconnected and create a region. Built on a succession of market regions, the foundation of an urban system is based on the activity level of each center in relation to the friction of distance. Cities, towns and rural areas make up the majority of a region's overall geographical organization.

• Manufacturing and mining agglomerations are formed by the proximity of key inputs like raw resources, skilled labor, and/or a ready supply of customers. The majority of a region's economic growth can be attributed to these export-oriented businesses.

• Administration, banking, retail and wholesale, and other comparable service industry sites that tend to agglomerate in a system of central places [cities] offering ideal access to employees or potential clients.

• There are patterns of transport nodes and links like roads, trains and ports that serve as a connection to the major economic hubs.

Jointly, these components define the spatial order of a region, principally their structure in a hierarchy of relationships including the mobility of passengers and freight. Such changes are geographically translated by more or less well-defined urban systems, with the most significant cities having the most connectedness and accessibility and the lower-order centers having less. This raises the question of whether or not city size has an impact on connection. Transport, urban systems and regional development are all intertwined in a variety of theoretical frameworks that include core-periphery development stages and theories of network expansions. There are three distinct types of regional spatial organization conceptualized as follows:

• Attempts are made by urban systems models / central places to discover the connections between a region's population density, urban size, and geographic distribution. Many variations on the regional spatial structure have been examined by the central places hypothesis. The vast majority of urban systems have a well defined and stable hierarchy where a few hubs dominate. Transportation is especially crucial in such a representation since the layout of central sites is centered on minimizing distance friction. The territorial organization portrayed by the central locations theory is the product of an area seeking the supply of services in a [transport] cost-effective way.

• Growth poles where economic development is the structural change caused by the growth of new industries that are the poles of growth. The catalyst for regional spatial organization is where these activities take place. Growth poles first initiate, then diffuse, development. Growth gets distributed within a regional urban system, but this process is uneven, with the core benefiting first and the periphery eventually becoming integrated with a system of flows. In the growing poles idea, transportation is a determinant of accessibility, which reinforces the necessity of poles.

• Transport corridors reflect an aggregation of flows and infrastructures of multiple modes with their development associated with economic, infrastructural, and technical processes. When these processes are engaging urban development, corridors are a system of cities oriented along an axis, often fluvial or a coastline that allows cities to maintain commercial contacts. BostWash [Boston – Washington] and Tokaido [Tokyo – Osaka] are just two examples of urban areas that share this geographical similarity. High-speed rail systems are being built all over the world along major urban corridors, reinforcing the regional spatial structure already in place.

4. Local Spatial Organization

Although transportation plays an important role in rural spatial organization, it is in urban areas that transportation has the greatest impact on local spatial organization. Urbanization and transport are connected ideas, notably with transport determining the size and extent of cities. Transportation of people [for employment, living, shopping, and recreation] and commodities is essential in every metropolis [consumption goods, food, energy, construction materials, and waste disposal]. The range and magnitude of urban mobility is a spatial translation of demographic and spatial change. Employment and attraction zones are the most essential aspects defining the local urban spatial organization:

• Employment zones: Motorized transport's success, particularly the personal vehicle, is largely to blame for the rising separation between the place of employment and the location of dwelling. Employment zones being positioned farther from residential zones have contributed to an increase in number and length of commuting trips. Prior to the development of the suburbs, all commuting was done via public transportation. The car is still the primary mode of transportation for most of these journeys, but there are many other options available in the city. This tendency is particularly widespread in heavily populated, industrialized, and urbanized zones, although motorization is also a major trend in developing countries.

• Zones of attraction: Attraction zones linked to transport modes are regions to which a big number of individuals may travel for purposes such as shopping, professional services, education, and recreation. There is a specific hierarchy of services within an urban area, similar to the central places theory, ranging from the central business district, which offers a wide range of specialized services, to small local centers, which provide basic services like groceries and personal banking. The central business district.

The growth of cities is conditioned by transport, and numerous modes, from urban transportation to the vehicle, have contributed to the building of urban landscapes. Three distinct phases can be noted:

• Conventional [classic] city: The old city was tiny and constricted in size because it was built for pedestrian interactions and constrained by them. The introduction of the first urban transit networks in the 19th century facilitated the extension of the metropolis into new districts. However, the vast bulk of moves were still made by pedestrians, and the local spatial structure remained compact. Many European and Asian cities still maintain a high level of compactness, where urban transit is a defining part of the spatial structure.

• Suburbanization: The introduction of more efficient urban transit systems and later of the vehicle facilitated an increased separation between primary urban functions [residential, industrial and commercial] and their geographical specialization. The fast development of urban areas that occurred, notably in North America, established a new spatial organization, less cohesive than before, but nonetheless relatively near to the existing urban fabric. Although this process started in the early 20th century, it increased in the 1950s.

• Exurbanization: Additional advances in mobility supported urban expansion in the countryside, where urban and rural activity are fairly intermixed. Residential districts, commercial centers, industrial parks, logistical hubs and high-tech zones have sprouted out all over cities that had previously been part of the metropolitan area. "Edge cities" are another term for these kinds of suburban outposts.

The vehicle has influenced contemporary urban spatial organization, but other socioeconomic variables have also shaped urban growth, such as gentrification and differential changes in land values. Automobility and the often-conflicting roles of cities have led to an urban growth that is dependent on the mobility of persons [residential, industrial, commercial]. Still, distance decay remains a force determining urban spatial organization since suburban and exurban developments tend to occur as concentric rings within large metropolitan areas. Transport thus adds to the local spatial arrangement. The city's morphologies must also be taken into consideration when designing it. The interdependence of transport infrastructure and urban centers cannot be overstated.