Is there a future for the skyway in American cities? Unlike retrofitting a new layer onto a well-established street grid and development pattern (as in Minneapolis), there’s an opportunity to use an extra pedestrian layer as a tool to help re-make suburban edge cities into places navigable by pedestrians.

In May, Jennifer Yoos and Vincent James published a brief history of grade separation for pedestrians in Places Journal – in other words, a history of the skyway.

There’s a common thread of unrealized grand visions. Victor Gruen’s plan for Downtown Forth Worth (1956) called for pedestrianizing the downtown, providing automobile access from a ring of parking garages accessed via skyways. The virtue of the plan was flexibility – the elements allowed for incremental implementation of the concept. Yoos and James write:

Gruen’s urban design proposals introduced something that could be described in contemporary terms as a form of tactical urbanism: a vocabulary of adaptable components, such as pedestrian bridges, plazas, and arcades, that could be deployed selectively. Construction could thus proceed incrementally, radically changing a city over time. Gruen’s plan for Fort Worth proposed to reorder the city around a central pedestrian plaza with shop­ping. Vehicles were relegated to the periphery, and elevated pedestrian bridges connected parking ramps to the walking zone at the urban core. Although it was framed within a compelling narrative that referred to everyday life in historic European cities, Gruen’s alternative was distinctly modernist.

The potential pitfalls of that approach were evident to Jane Jacobs from the start, with her prescient observation about the impact of a partial implementation:

While she broadly endorsed Gruen’s social programming, she warned that clients and others who enacted his plans would overlook that critical point, focusing instead on his strategies for traffic management. And as she predicted, Gruen’s model for incremental development proved tenuous as his proposals — or something like them — were built in cities across the country. Local governments implemented only those components that were desirable at a given time to particular political constituencies, with little regard for the whole. The concept of a vehicle-free center was often abandoned as the cities evolved. The socially-oriented urbanism that was so crucial to Gruen’s vision demanded a more integrated and comprehensive approach.

Indeed, this was my personal experience with skyway networks growing up in Minneapolis. The skyways provide climate controlled, grade separated pedestrian circulation. The provision of skyways allowed the city to use street space for vehicle movement, relegating pedestrians to inhospitable sidewalks or to second-level skyways that require navigation through a warren of privately owned and controlled spaces.

Conventional wisdom in Minneapolis holds that despite the drawbacks of the skyway system, it was a necessary move for downtowns like Minneapolis to make in order to compete against ascendant suburban shopping malls – such as Victor Gruen’s own Southdale Center. The flaw in the approach is for a naturally walkable and compact downtown to try and beat an auto-oriented shopping mall at its own game – it requires an assumption that the streets must prioritize car movement to compete with freeways.

Not that Victor Gruen would declare victory over downtown. His vision for Southdale was for a new kind of mixed use town center to surround the shopping mall – uses that never came. Another vision only partially implemented.

Yoos and James close with observations from Hong Kong, where the logic of separating pedestrians and cars ‘works’ best; combined with the required density to achieve critical mass (something often lacking in Minneapolis), challenging terrain requiring vertical pedestrian movement in any context, and a great deal of redevelopment activity to re-shape the city as a multi-layered place:

Elevated walkway systems now span the majority of the Sheung Wan, Central, Admiralty, and Wan Chai districts. The pedestrian network features a range of connector prototypes, including deck-access plazas and podiums, flyover bridges, open-air footbridges, and high-bridge networks (exterior pedestrian bridges over streets), interiorized walkways, elevated parks, and exterior escalators that scale the steep hillsides.

Yoos and James note that one factor to Hong Kong’s success with the strategy is total commitment: “Hong Kong’s lack of a significant historic conservation agenda” and the government ownership of all land results in a more complete implementation of the concept.

In the United States, a comparison to Hong Kong has limited applicability. However, I don’t think that means the future for multi-layered cities is dead. Path dependence means places like Minneapolis won’t be tearing out their skyways anytime soon, but the future for the concept is probably in urbanizing edge cities like Tysons Corner.

The plans for Tysons involve a massive redevelopment of an auto-oriented edge city into a transit-oriented and walkable one. Both increased density and successful transit require good pedestrian access. Tysons already has islands of walkable places inside the malls and the plan calls for incrementally creating a new grid of streets as redevelopment proceeds.

  

Connecting those places to the transit system requires either taming massive suburban quasi-highways, or moving pedestrians over/under them in another way.

The first phase of redevelopment at Tysons Corner Center is adding a pedestrian layer above the traffic, directly linking the Mall’s second level to the mezzanine of the rail station. A new hotel faces onto the pedestrian plaza, with loading and valet parking located one level below. The natural topography allows for a person to walk from the Metro station to the plaza (via a pedestrian bridge) to the mall on a single level, with auto movement below.

For the Mall, the additional development adds new uses (office, residential, hotel), stepping towards fulfillment of Gruen’s vision of a mixed use town center. Restaurants and bars dominate the new retail offerings, fronting onto the plaza as an attempt to create a sense of place as well as a functional pedestrian connection.

The sturm und drang over putting the Metro underground in Tysons missed the challenge of mixing pedestrians with suburban arterial roads. The elevated rail structure isn’t the obstacle to creating a walkable place – the cars are. And skyways might help provide a working alternative.