The Issue of Multilevel Pedestrian Urbanism
Public space is entangled with the contemporary spatial, social, cultural, political, and economic challenges cities are facing. It is one of the critical concepts to tackle to ensure sustainable, just, equitable, and resilient cities, in alignment with the New Urban Agenda resolution, adopted at the United Nations Habitat II Conference in Ecuador (United Nations, 2017). Discussions on public space note a general tendency in under-management and over-management, creating neglected, invaded, exclusionary, segregated, privatized, consumption, invented, and commercial spaces (Carmona, 2010). It seems public space can no longer be perceived as a singular notion of ownership or accessibility, but is instead a cluster concept, as Kohn (2004) defines it.
One of the manifestations of the ongoing transformations of urban public spaces is multilevel pedestrian urbanism, in particular, the proliferation of grade-separated pedestrian systems (GSPS), pedestrian-only precincts elevated or sunken from the street level. As it has emerged in a number of locations worldwide, the concept is referred to by a variety of names, including skywalks, elevated walkways, tunnel systems, underground pedestrian systems (UPS), climate-controlled walkways, interior city, multilevel networks or vertically integrated environments. The networks also tend to have a local name, like the Skyway in Minneapolis or the PATH in Toronto.
The idea of separating pedestrians and cars has its roots in the modernist principles of city planning, and it was first proposed by the Congrès International d’Architecture Moderne (CIAM) in the 1930s. The goal was to allow for a smooth and speedy flow of vehicular traffic while simultaneously protecting pedestrians (Le Corbusier, 1973, pp. 81–83). The prioritization of cars in cities has led to the development of GSPS, creating public spaces invaded, determined, and usurped by vehicular traffic (Lefebvre, 1991, p. 359). Moreover, late capitalism and a consumerist culture have resulted in the privatization of public spaces (Madanipour, 2003) in turn fueling segregated and exclusionary GSPS of large corporate or residential developments. Commercialization and privatization of public space have also allowed economic reasoning to delaminate streets in hopes of acquiring further profits (Byers, 1998; Maitland, 1992). Grade-separated spaces, present in large numbers and influencing cities worldwide, function far beyond infrastructure, covertly delaminating, privatizing, and segregating the traditional urban streetscape (Boddy, 1994, p. 127).
Some of the largest networks are in North America, with the first skywalk constructed in Minneapolis, USA, in 1962. While some cities are demolishing or limiting their GSPS networks, others are continuously producing far-stretching elevated pedestrian landscapes, often as a part of the privatization of public urban space. During the last couple of decades, the phenomenon of elevated GSPS has received a new wave of attention, not only with an increased amount of research but also the proliferation of elevated public space proposals (Yoos & James, 2016, p. 15), succeeding the successful transformation of an old rail line in the project of New York’s High Line by James Corner Field Operations and Diller Scofidio and Renfro between 2009 and 2014. One example is the conversion of a stretch of highway initially intended for demolition in Seoul by MVRDV, and another is the proposal of an elevated urban park in Atlanta by Rogers Partners and Nelson Byrd Waltz.
How should we tackle the challenges of the layering and stratification of public space, one of the fundamental building blocks of urban fabric? What is the next step for the development of GSPS networks and can we learn from the existing systems? There is little research on the roles GSPS play in the context of public space, especially given their consistent treatment as infrastructure undeserving attention. As parts of the daily experience of millions of urbanites around the world, these structures deserve our attention.
References
Boddy, T. (1994). Underground and Overhead: Building the Analogous City. In Michael Sorkin (Ed.), Variations on a Theme Park: The New American city and the End
Byers, J. (1998). The Privatization of Downtown Public Space: The Emerging Grade-Separated City in North America. Journal of Planning Education and Research, 17(3), 189–205. https://doi.org/0803973233
Carmona, M. (2010). Contemporary Public Space: Critique and Classification, Part One: Critique. Journal of Urban Design, 15(1), 123–148. https://doi.org/10.1080/13574800903435651
Kohn, M. (2004). Brave New Neighborhoods – The Privatization of Public Space. New York and London: Routledge. https://doi.org/10.1017/CBO9781107415324.004
Le Corbusier. (1973). The Athens Charter. New York: Grossman Publishers.
Lefebvre, H. (1991). The Production of Space. Oxford: Basil Blackwell.
Madanipour, A. (2003). Public and Private Spaces of the City. Abingdon, UK: Taylor & Francis. https://doi.org/10.4324/9780203402856
Maitland, B. (1992). Hidden Cities: The Irresistible Rise of the North American Interior City. Cities, 9(3), 162–169.
United Nations. (2017). New Urban Agenda.
Yoos, J., & James, V. (2016). Parallel Cities: The Multilevel Metropolis. (A. Blauvelt, Ed.). Minneapolis: Walker Art Center.
