C+S March 2020 Vol. 6 Issue 3 (web)

The world’s cities are booming, and their growth is changing the face of the planet. Rapid urbanization in developing countries—the gradual shift in residence of the human population from rural to urban areas— is both a challenge and an opportunity to steer the world towards a more sustainable trajectory. The latest UN World Cities Report 1 found that the number of “mega- cities”—those with more than 10 million people—has more than doubled over the past two decades, from 14 in 1995 to 29 in 2016. Projections 2 show that urbanization combined with the overall growth of the world’s population could add another 2.5 billion people to urban areas by 2050, with close to 90 percent of this increase taking place in Asia and Africa. Traffic congestion is a serious consequence of urbanization in any country, with significant negative effects on both the quality of life and the economy. In addition to the time wasted, traffic congestion results in unnecessary fuel consumption, causes additional wear and tear on vehicles, increases harmful emissions lowering air quality, and increases the costs of transport for business. Due in part to traffic, cities and megacities produce more than 70 percent of world’s anthropogenic CO2 emissions. According to the World Bank (2018) 3 , as the developing world rapidly urbanizes, there is an opportunity to build safer, cleaner, more efficient, and more accessible transport systems that reduce congestion and pol- lution, facilitate access to jobs, and lower transport energy consump- tion. In emerging mid-size cities, where most of the new urban dwellers will live 4 , city planners have an opportunity to design sustainable and inclusive transport systems from the start, leapfrogging more polluting and costly methods of transport. In older or larger cities, technology and big data are helping to bet- ter map travel patterns and needs, to engage citizens, and to improve the quality and efficiency of transport solutions. There are several ap- proaches to this ranging from the provision of enhanced bus services and dedicated bus lanes, creation of pedestrian areas with access only by public transport, to the creation of new light rail and urban rail services. One clear solution to the problem of traffic congestion is to reduce the reliance on the use of private vehicles by restricting their use in urban areas with the introduction of congestion charges, or by removing them from the streets altogether. As an alternative, adequate, modern, easily accessible public transport should be offered to the travelling public. Construction Challenges of Rail in an Urban Environment Land Development

Photo: UN World Cities Report

In a rapidly urbanizing world, the urban rail system is an efficient way of reducing traffic congestion, reducing emissions, and decreasing pol- lution. The high capacity offered by rail systems can serve the high transport requirements generated within and between cities. Compact, mixed-use, pedestrian-friendly development organized around a mass transit station is one of the most effective strategic initiatives to address the negative effects of motorization and identifies rail transit systems as the backbone of urban development. The presence of railway stations in city centers enables effective intra- modality through transfers to urban public transport services in addi- tion to cycling, walking, car sharing, and city logistics. The introduc- tion of an urban rail system can be popular and politically attractive, but the cost is high, and in many cases, improving bus services will have a greater benefit than installing street-running trams and metros. However, rail-based transport is appropriate where there is a need to move large volumes of people (in the order of 10,000 per hour) be- tween major centres (e.g. a transport hub and the city center). Urban rail is segregated into metro, light rail transport (LRT), and tramways. Metro rail projects typically involve below ground, at grade, and elevated sections with multiple-unit trainsets. LRT is traditionally aboveground and both LRTs and metros operate in dedicated guide- ways. In contrast, tramways mainly follow existing road and paved area configurations, mixed in with normal road and foot traffic. Where new urban centres are being constructed, it is possible to fully segregate

Photo: Railsystem.net


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