With urbanization and urban densities increasing around the world, mobility solutions such as the automation of metros, BRT or scalable light rail systems have proven successful in meeting the ever-growing capacity demands. With these solutions now in place, the focus in the future could shift towards more accessibility to and from transit stations. If this is the case, could elevated connectors such as walkways, people movers and cable cars be the next pieces in the urban mobility puzzle?
As part of our series of interviews with guests speakers at the next World Congress & Exhibition, UITP questioned Arnd Bätzner, Physicist, Pianist and Researcher at University of St. Gallen in Switzerland, ahead of his talk on “Moving to the Third Dimension: Efficient Proximity Mobility through Elevated Urban Connectors” on Tuesday 9 June.
What examples of cities can you name where systems such as elevated walkways, people movers and cable cars have been successfully implemented?
Today, the most advanced systems of Elevated Walkways/Skywalks can be found in the Asian Mega-Cities of Hong Kong and Singapore, as well as in Japanese cities. As for Cable Cars, they are micro-connectors mostly located in the Global South, in cities such as Medellin in Colombia and Caracas in Venezuela, as well as Constantine in Algeria. These current, "new" systems can all be considered a success because they focus implicitly or explicitly on walkability.
In contrast, “old” legacy skywalk networks built in cities such as Cincinnati, Minneapolis - St. Paul and Ann Arbor during the 1960s wave of "Neo-Futurist " urbanism all failed because their approach relied implicitly on an automobile-centred design. They have all been demolished.
For the exact same reason, people movers or PRT (personal rapid transit), despite technically correct capacity calculations, have failed almost everywhere, think of Detroit, except outside airports and amusement parks.
So the lessons to be drawn from these experiments is that a walkability-centred approach is required, putting the user (as a pedestrian and transit user) at the centre of all reflexions and physical infrastructure designs.
So under which conditions and circumstances do these systems fit best?
Elevated connectors function best in highly dense urban environments where congestion or the threat of congestion can be observed on the ground. This mainly concerns pedestrians, but can also include cyclists. Examples can be found at street-level multiple crossings, where densities of pedestrian traffic negatively affect travel times, space on the ground is limited, there is interference with the operation of other transport modes, and/or for reasons of comfort.
Do you have any preliminary findings on the impact on modal split?
Yes, mirrored in the two key indicators (1) motorized road traffic decrease and (2) real estate value, both escalator systems in Hong Kong (Central-Mid Levels and Sai Ying Pun) have proven to be a success in amplifying transit accessibility. The elevated walkways there have a double function - boosting micro-mobility (translated into easier accessibility) and extending the catchment areas of rail stations. Trips that would previously not have been made using transit are now facilitated (in both comfort and time) to the extent that public transport modal share measurably increases, and so does the overall system performance (e.g. decrease of taxi trips and thus more fluid road traffic).
Are there any innovative design recommendations you can give for improved accessibility that could facilitate intermodality?
The charm of the solutions proposed here are that they can be implemented comparably quickly and at comparably low cost in virtually any grown and pre-existing urban topology - be it a formal city that grew according to pre-established guidelines or any other type of informal urbanism. Elevated connectors are also perfectly adaptable retrofits. Implementing an elevated transport infrastructure implicitly constitutes a formalizing intervention, since future urban development will be affected by, attracted by and aligned with the new transport link.
Generally, the design should focus on putting the users' needs first. Here again, very simple measures can result in amazing successes. A shading of walkway networks greatly increases their usability in sun and rain, as both Singapore and Hong Kong have demonstrated in impressive ways. For very harsh climates, such as in the cities of the Middle East, enclosed and air-conditioned walkways can be a more complex evolution.
Comparative analysis from case studies shows that mechanization is required wherever physical movement is psychologically or physically cumbersome. This can include aspects like an objectively short, but monotonous passageway that is experienced as "dull" by users. From escalators over walkways - at static or variable (accelerating/decelerating) speeds – cable cars and people movers, these mechanical aids are not to be considered as standalone urban transport systems, but "walking enhancers" - tools that facilitate walkability in a specific location. In the way they are considered here, they operate on short- to medium-length distances, but at high frequency and capacity. This implies a whole set of consequences in the way they are to be perceived by users from their representation in transit system maps (as a part of walkway networks) to providing the most adapted mode to the right place. It can be shown that the immediate availability of departures at any given time are qualities in themselves, independent from hourly capacity considerations. The key here is that the natural flow of walking with the attached, intuitive sense of progression shall not be interrupted, otherwise, the mechanical transport aid will not be considered a support, but an obstacle.
In terms of connecting to other modes, general design recommendations for transit stations apply with particular rigour: the easier, the more intuitive, the more comfortable the transition from walkway/elevated connector to rail, bus or any other transit will be, the more the combination of both modes will be attractive, and the greater the long-term modal share. It is thus important to re-consider transit terminal and station design from this perspective. The past decades have brought a focus mainly on capacity, now usability and comfort need to gain equal weight in design considerations.
Do you have a main message you would like to get across in your talk at the Congress in Milan?
All too often, engineering and architectural discourses unfold on two different levels, by different groups of scholars and in different technical idioms. Today's complexities of both urban design and transport planning have now reached a level where finding a common language, and understanding the "other" side's thinking and approaches, become a prerequisite for any design of innovative, future-proof and financially operable solutions. The requirement to think in holistic urban design processes, to take a broad, trans-disciplinary approach, is thus more than a buzzword, but a necessity to secure both liveable cities and a prosperous future for transit design. Thus, we do not only need to learn to think intra-modal, but also extra-modal, understanding and anticipating people's lives.
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