Bridging: Transportation - Chapter 8 - Urban Transportation - PDF

BRIDGING: TRANSPORTATION CHAPTER 8: URBAN TRANSPORTATION CONCEPT 1: TRANSPORTATION AND THE URBAN Global urbanisation Urbanization. The process of transition from a rural to a more urban society. Statistically, urbanization reflects an increasing proportion of the population living in settlements de...

BRIDGING: TRANSPORTATION CHAPTER 8: URBAN TRANSPORTATION CONCEPT 1: TRANSPORTATION AND THE URBAN Global urbanisation Urbanization. The process of transition from a rural to a more urban society. Statistically, urbanization reflects an increasing proportion of the population living in settlements defined as urban, primarily through net rural to urban migration. The level of urbanization is the percentage of the total population living in towns and cities while the rate of urbanization is the rate at which it grows. 2 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM Global urbanization is the outcome of three main demographic trends: ❑ Natural increase. The outcome of more births than deaths in urban areas, a direct function of the fertility rate as well as the quality of healthcare systems (lower mortality rates, particularly for infants). Phases in the demographic transition are commonly linked with urbanization rates. Although natural increase played an important role in the past, it is of much lesser importance today as fertility rates in many developed countries have dropped significantly, in some cases like Western Europe, Japan and South Korea below replacement rate. 3 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM ❑ Rural to urban migrations. This has been a strong factor of urbanization, particularly in the developing world where migration accounted between 40% and 60% of the urban growth. Such a process has occurred since the beginning of the industrial revolution in the 19th century, first in the developed world and then in the developing world. The factors behind urban migrations are numerous and may involve the expectation to find employment, improved agricultural productivity which frees rural labor or even political and environmental problems where populations are constrained to leave the countryside. 4 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM ❑ International migration. The growth in international migration has been an important factor in the urbanization of major gateway cities, such as Los Angeles, Miami, New York, London and Paris including Johannesburg. This process tends to take place in the largest cities, but there is a trickle down to cities of smaller size. 5 Urbanisation, trends, causes and effects In 1950, only a third of world population lived in rural areas Urban population of the world has grown from 746 million in 1950 to 3.9 billion in 2014 World urban population projected to increase to 66% by 2050 Number of mega-cities (more than 10 million people) has grown 3 times since 1990 and there are now 34 mega-cities in the world By 2030, 41 urban agglomerations are projected to house at least 10 million inhabitants each Rate of urbanization in Africa increased from 15% in 1960 to 40% in 2010 and is projected to reach 60% in 2050 Rapid rate of urbanization in Africa is a result of natural growth (high birth rates), rural urban migration High growth in population has increased pressure on services including transport 6 Urbanisation in South Africa South Africa has the largest and most industrialised economy in Africa Sixty-two (62%) of the population live in urban areas Urbanisation process in the late 19th and early 20th centuries was closely associated with industrialisation and stimulated by the discovery of diamonds in the interior of the country in 1867, and gold in 1884 The urbanisation process in South Africa was shaped historically by policies to control the movement of black people The pace of urbanisation accelerated during the 1980s when rural-urban movements increased after many of the restrictions of apartheid proved impossible to enforce and subsequently the fall of apartheid. 7 Urban population of South Africa, 1911–2001 Year Number of urban Total National Share of urban areas population population population (over 5000 people) (thousand) (thousand) (%) 1911 25 1 085 5 973 18.2 1021 36 1 369 6 927 19.8 1936 53 2 476 9 588 25.8 1951 89 4 463 12 671 35.2 1960 120 6 066 15 994 37.9 1970 161 8 986 23 311 38.5 1980 183 12 419 29 208 42.5 1991 244 17 327 38 012 45.6 1996 280 21 674 49 580 53.4 2001 307 25 355 44 819 56.6 Source: Turok 2012 8 Impacts/Effects of Urbanisation Overpopulation Housing shortage Cost of living increases Availability of infrastructure facilities, e.g. water, hospitals, schools becomes a problem and are not up to standard Stress Increased crime rates Urban sprawl 9 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM Urban form Urbanization has been shaped by transport infrastructure, such as roads, transit systems or simply walkways. Consequently, there is a wide variety of urban forms, spatial structures and associated urban transportation systems. Urban form. Refers to the spatial imprint of an urban transport system as well as the adjacent physical infrastructure. Jointly, they confer a level of spatial arrangement to cities. Urban spatial structure. Refers to the set of relationships arising out of the urban form and its underlying interactions of people, freight and information. It tries to evaluate to what extent specific urban structures can be achieved with specific transport systems. 10 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM In light of transport developments, the urban spatial structure can be categorized by its level of centralization and clustering: Centralization. Refers to the setting of activities in relation to the whole urban area. A centralized city has a significant share of its activities in its center while a decentralized city does not. Large employers such as financial institutions are the main drivers of centralization. Clustering. Refers to the setting of activities in relation to a specific part of the urban area. A cluster of activities is therefore a concentration around a specific focal point, which tend to be transport infrastructure such as a highway interchange, a transit terminal or a smaller town that has been absorbed by the expansion of the metropolis. 11 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM Even if the geographical setting of each city varies considerably, the urban form and its spatial structure are articulated by two structural elements: Nodes. These are reflected in the centrality of urban activities, which can be related to the spatial accumulation of economic activities or to the accessibility to the transport system. Terminals, such as ports, train station, railyards, and airports, are important nodes around which activities agglomerate at the local or regional level. Nodes have a hierarchy related to their importance and contribution to urban functions, with high order nodes such as management and retailing and lower order nodes such as production and distribution. Linkages. This refers to the infrastructure that supports flows from, to and between nodes. The lowest level of linkages includes streets, which are the defining elements of the urban spatial structure. There is a hierarchy of linkages moving up to regional roads and railways and international connections by air and maritime transport systems. 12 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM Dispersion, or urban sprawl, is taking place in many different types of cities, from dense, centralized European metropolises such as Madrid, Paris, and London, to rapidly industrializing metropolises such as Seoul, Shanghai, and Mexico City, to those experiencing recent, fast and uncontrolled urban growth, such as Johannesburg, Mumbai, Jakarta and Lagos. What are the consequences of urban sprawl? 13 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM The Spatial Constraints of Urban Transportation The amount of urban land allocated to transportation is often correlated with the level of mobility. In the pre-automobile era, about 10% of the urban land was devoted to transportation which was simply roads for a dominantly pedestrian traffic. As the mobility of people and freight increased, a growing share of urban areas was allocated to transport and the infrastructures supporting it. Large variations in the spatial imprint of urban transportation are observed between different cities as well as between different parts of a city, such as between central and peripheral areas. The major components of the spatial imprint of urban transportation are shown in the next set of slides: 14 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM Pedestrian areas. Refer to the amount of space devoted to walking. This space is often shared with roads as sidewalks may use between 10% and 20% of a road’s right of way. In central areas, pedestrian areas tend to use a greater share of the right of way and in some instances whole areas are reserved for pedestrians. However, in a motorized context, most pedestrian areas are for servicing people’s access to transport modes such as parked automobiles. Roads and parking areas. Refers to the amount of space devoted to road transportation, which has two states of activity; moving or parked. In a motorized city, on average 30% of the surface is devoted to roads while another 20% is required for off-street parking. 15 CONCEPT 1: TRANSPORTATION AND THE URBAN FORM Cycling areas. Attempts have been made to create spaces specifically for bicycles in urban areas, with reserved lanes and parking facilities. The Netherlands has been particularly proactive over this issue with biking paths parts of the urban transport system; 27% of the total amount of commuting is accounted by cycling. (Why is the proportion of people who cycle in South African cities negligible?) Transit systems. Many transit systems, such as buses and tramways, share road space with automobiles, which often impairs their respective efficiency. Attempts to mitigate congestion have resulted in the creation of road lanes reserved to buses either on a permanent or temporary (during rush hour) basis. Other transport systems such as subways and rail have their own infrastructures and, consequently, their own rights of way. Transport terminals. Refer to the amount of space devoted to terminal facilities such as ports, airports, transit stations, railyards and distribution centers. Globalization has increased the mobility of people and freight, and consequently the amount of urban space required to support those activities. Many major terminals are located in the peripheral areas of cities, which are the only locations where sufficient amounts of land are available. 16 CONCEPT 2: URBAN LAND USE AND TRANSPORTATION Transportation and urban dynamics The most significant components of urban dynamics are: ❑Land use This is the most stable component of urban dynamics, as changes are likely to modify the land use structure over rather a long period of time. The main impact of land use on urban dynamics is its function as a generator and attractor of movements. 17 CONCEPT 2: URBAN LAND USE AND TRANSPORTATION ❑Transport network This is considered to be a rather stable component of urban dynamics, as transport infrastructure are built for the long term. This is particularly the case for large transport terminals and subway systems that can operate for a very long period of time. For instance, many railway stations are more than 100 years old. The main contribution of the transport network to urban dynamics is the provision of accessibility. Changes in the transport network will impact accessibility and movements. 18 CONCEPT 2: URBAN LAND USE AND TRANSPORTATION ❑Movements The most dynamic components of the system, since movements of passengers or freight reflect changes almost immediately. Movements thus tend more to be an outcome of urban dynamics than a factor shaping them. ❑Employment and workplaces They account for significant inducement effects over urban dynamics since many models often consider employment as an exogenous factor. This is specifically the case for employment that is categorized as basic, or export-orientated, which is linked with specific economic sectors such as manufacturing. Commenting is a direct outcome of the number of jobs and the location of workplace. 19 CONCEPT 2: URBAN LAND USE AND TRANSPORTATION ❑ Population and housing They act as the generators of movements, because residential areas are the source of commuting. Since there is a wide array of incomes, standards of living, preferences and ethnicity, this diversity is reflected in the urban spatial structure. 20 CONCEPT 3: URBAN MOBILITY (1) The consideration of urban movements, both for passengers and freight, involves their generation, the modes and routes used and their destination: ❑ Trip generation. Trip generation is the first step in the conventional four-step transportation forecasting process used for forecasting travel demands. It predicts the number of trips originating in or destined for a particular traffic analysis zone ❑ Trip distribution is a process by which the trips generated in one zone are allocated to other zones in the study area ❑ Modal split. Implies the use of a series of transportation mode for urban trips, which is the outcome of a modal choice. This choice depends on a number of factors such as cost, technology, availability, preference, travel time (distance) and income. ❑ Trip assignment (routing). Involves which routes will be used for journeys within the city. For instance, a commuter driving a car has most of the time a fixed route between his residence and place of work. This route may be modified if there is congestion or if another activity (such as shopping) is linked with that trip; a practice often known as trip chaining. 21 CONCEPT 4: URBAN TRANSPORT PROBLEMS (1) Challenges facing urban transportation Traffic congestion and parking difficulties Congestion is one of the most prevalent transport problems in large urban agglomerations, usually above a threshold of about 1 million inhabitants. By the 21st century, drivers would spend about 3 times more time in congestion as they did in the later part of the 20th century. Congestion is particularly linked with motorization and the diffusion of the automobile, which has increased the demand for transport infrastructures. However, the supply of infrastructure has often not been able to cope with the growth of mobility. Since vehicles spend the majority of the time parked, motorization has expanded the demand for parking space, which has created space consumption problems particularly in central areas; the spatial imprint of parked vehicles is significant. 22 Challenges facing urban transportation : Traffic congestion and parking difficulties There are two main types of congestion: Recurrent congestion: Defined as congestion that occurs due to routine traffic volumes operating in a typical environment present on a normal day if nothing bad has happened on the roadway Recurrent congestion is influenced by factors such as rapid population growth, urbanization and related growth in car ownership and use Non-recurrent congestion Defined as unexpected, unusual or random incidents which are caused by external factors which include: Lane blocking due broken down vehicles and debris in the roadway Accidents, which forces vehicles to drive slowly or even results in the lane being closed Lane closures resulting from construction and maintenance activities Malfunctioning traffic signals. This is a common phenomenon in Sub Saharan African cities Adverse environment such as whether, gradients, poor visibility, rain, potholes and the like. In some countries, potholes can go for several months without being attended to. Trading taking place on the sides of streets which effectively reduces the width of the road 23 CONCEPT 4: URBAN TRANSPORT PROBLEMS (2) ❑Longer commuting On par with congestion people are spending an increasing amount of time commuting between their residence and workplace. An important factor behind this trend is related to residential affordability as housing located further away from central areas (where most of the employment remains) is more affordable. Therefore, commuters are trading time for housing affordability. However, long commuting is linked with several social problems, such as isolation, as well as poorer health (obesity). 24 CONCEPT 4: URBAN TRANSPORT PROBLEMS (3) ❑Public transport inadequacy Many public transit systems, or parts of them, are either over or under used. During peak hours, crowdedness creates discomfort for users as the system copes with a temporary surge in demand. Low ridership makes many services financially unsustainable, particularly in suburban areas. In spite of significant subsidies and cross-financing (e.g. tolls) almost every public transit system cannot generate sufficient income to cover its operating and capital costs. While in the past deficits were deemed acceptable because of the essential service public transit was providing for urban mobility, its financial burden is increasingly controversial. 25 CONCEPT 4: URBAN TRANSPORT PROBLEMS (4) ❑Difficulties for non-motorized transport These difficulties are either the outcome of intense traffic, where the mobility of pedestrians, bicycles and other non-motorized vehicles is impaired, but also because of a blatant lack of consideration for pedestrians and bicycles in the physical design of infrastructures and facilities. On the opposite side, the setting of bicycle paths takes capacity away from roadways as well as parking space. 26 CONCEPT 4: URBAN TRANSPORT PROBLEMS (6) ❑High infrastructure maintenance costs Cities with an aging of their transport infrastructure are facing growing maintenance costs as well as pressure to upgrade to more modern infrastructure. In addition to the costs involved, maintenance and repair activities create circulation disruptions. Delayed maintenance is rather common since it conveys the benefit of keeping current costs low, but at the expense of higher future costs and on some occasion the risk of infrastructure failure. The more extensive the road and highway network, the higher the maintenance cost and the financial burden. 27 CONCEPT 4: URBAN TRANSPORT PROBLEMS (7) ❑Environmental impacts and energy consumption Pollution, including noise, generated by circulation has become a serious impediment to the quality of life and even the health of urban populations. Further, energy consumption by urban transportation has dramatically increased and so the dependency on petroleum. These considerations are increasingly linked with peak mobility expectations where high energy prices incite a shift towards more efficient and sustainable forms of urban transportation, namely public transit. 28 CONCEPT 4: URBAN TRANSPORT PROBLEMS (8) ❑Accidents and safety Growing traffic in urban areas is linked with a growing number of accidents and fatalities, especially in developing countries. Accidents account for a significant share of recurring delays. As traffic increases, people feel less safe to use the streets. 29 CONCEPT 4: URBAN TRANSPORT PROBLEMS (9) ❑Land consumption The territorial imprint of transportation is significant, particularly for the automobile. Between 30% and 60% of a metropolitan area may be devoted to transportation, an outcome of the over-reliance on some forms of urban transportation. Yet, this land consumption also underlines the strategic importance of transportation in the economic and social welfare of cities. 30 CONCEPT 4: URBAN TRANSPORT PROBLEMS (10) ❑Freight distribution Globalization and the materialization of the economy have resulted in growing quantities of freight moving within cities. As freight traffic commonly shares infrastructure with the circulation of passengers, the mobility of freight in urban areas has become increasingly problematic. City logistics strategies can be established to mitigate the variety of challenges faced by urban freight distribution. Many dimensions to the urban transport challenge are linked with the dominance of the automobile. What measures can be implemented to alleviate the delivery of freght in urban areas? 31