Factors in Mass Transit System Decisions

The implementation of mass transit systems in urban environments is a complicated task, involving local politics, public approval, and geographic location. According to a paper by Working Group 13 of the International Tunnelling Association, the choice of constructing mass transit systems above ground or below ground rests largely on the urban environment and public values of the city. Through surveying 30 cities in 19 countries across 4 continents, the authors sought to understand the key reasons behind why mass transit systems are constructed so differently around the world. A clear conclusion was made about the cost effectiveness and time savings of some forms of mass transit systems. In a broad scope, the differences in cost among at-grade, above-grade, and below-grade transit systems were simplified into a 1/3/6 ratio, with below-grade being the most taxing. While the cost of digging tunnels and installing the infrastructure for such systems has steadily declined with improvements in technology, the price of modern amenities and safety regulations has kept the overall cost steady.

The high cost of underground Metro systems is rewarded with the highest time savings and reliability of any other possible mode, saving up to one hour per day for commuters in cities like Budapest and saving 1.5 million public minutes per day in Taipei. The construction of mass transit systems even offers the indirect benefit of reducing traffic congestion for car drivers, as seen in Tokyo where the construction of mass transit systems reduced the number of cars in the region by 15 million. Underground transit systems were also preferred in dense urban centers for their ability to “penetrate the existing urban fabric,” preserve the environment, and avoid above ground barriers. Above ground transit systems present reversed costs and benefits to underground systems. Above ground systems are typically constructed in newer cities with lower land cost, and when mixed with more affordable above ground construction practices are seen as the more affordable option. In most cases where the choice of constructing either above ground or underground systems were available, above ground systems were chosen due to cost effectiveness. Above ground systems come with the issue of being unsightly “urban blight,” and historically some systems have been removed after facing public opposition. The authors recognize that choosing the right form of transit system for a city is an

extraordinarily complicated task, and therefore they urge planners and policy makers to consider the longevity of such systems. The authors state that few cities have come to regret their choice in implementing mass transit systems, so making the proper investment to help such a system stand the test of time is imperative.