Cable cars are taking Latin America by a storm

A cable car above Caracas. Image: Getty.

Cable cars are a transportation system composed of a series of cars suspended from thick cables supported by large, widely spaced towers. The name can be confusing in an American context, where it generally refers to cable-drawn rail cars such as the trolleys of San Francisco; instead, such systems are often referred to as “chairlifts”, or (this is cute) “gondola lifts”.

Whatever you call them, the technology has long been used at ski lifts, and they’re a favourite attraction at amusement parks as well. But recently, they’ve found a new application: public transport.

This new wave of urban chairlift construction kicked off in Medellín, Colombia, which introduced the new system to serve underprivileged hilltop neighbourhoods. Each line was given a letter and colour, in a move which deliberately echoed the branding of the city’s existing metro system.

Construction of the new system, the Metrocable Medellín, was completed in 2004. Soon, the idea caught on across Latin America, and cable cars began hauling passengers in major cities such as Caracas, Manizales, Rio de Janeiro, and most recently La Paz, Bolivia.

The official map of Medellín's tranpsort network, showing traditional metros, cable cars and bus rapid transit lines.

It’s easy to understand why these systems draw so much attention. Unlike buses, which grumble along at street level, and subways which are buried out of sight, cable cars soar majestically above the cityscape, offering dramatic views to riders.

But the reason they’ve taken off in Latin America, and especially in mountainous cities where informal developments tend to concentrate on hilltops, is for their ease of construction over steep terrain. Bus-based public transit is often unreliable or unavailable to slum dwellers, and in hilly neighbourhoods buses are slowed by twisting streets. Cable cars, by contrast, glide effortlessly over these areas.

Such systems have in many cases been created with the express purpose of making life better for people living in slums, while showing respect for the autonomy of such communities. Arturo Brillembourg, an architect with Urban Think Tank and one of the developers of the Caracas Metrocable, said in an interview with Architonic: “Our concept is based in architecture that has the ability to change according to the transformation of the informal city and the dynamics among its inhabitants. We only provide the framework for future adaptation.”

These noble ideas of community empowerment are echoed by the writing on the cars themselves, emblazoned with bold slogans like “social ethics”, “participation”, and “love” (also, simply “Venezuela”). Cars in Medellín aren’t so outspoken, but their human representatives are. A headline from the website El Colombiano proclaims: “The Metrocable is quality of life”.

But the cars are not without their technical drawbacks. First, their capacity is much lower than conventional mass transit: a system designed for high capacity can typically haul 3,000 people per hour in each direction, which sounds like a lot until you consider that the same number of people can be carried by just three subway trains. They’re also slower than conventional transit, ambling along at 10 mph (16 kmh), the speed of a leisurely bike ride. And then there’s the safety issue. While proponents maintain that chairlifts are statistically very safe, the idea of dangling in a car suspended hundreds of feet above the ground from a cable no thicker than your wrist is still enough to make many riders squeamish.

The public response to these systems has varied. In Medellin, it’s been one of almost unanimous support: proponents boast of sharp drops in crime and increases in investment, crediting it as one of the keys to the “Medellin miracle” in which the city turned itself around after widespread drug-related violence in the 80s and 90s. In Caracas, the cable cars have become so much a part of daily life that users angrily lashed out after an unannounced closure in late 2012. La Paz’s system seems to be doing well, too; despite initial concerns about price, a report last month found the system to be a success.

Those in Rio de Janeiro have been somewhat less successful, however. A report from the website Rio on Watch noted that ridership was lacklustre, despite the fact that the line has worked well for some residents of the Complexo do Alemão favela that it serves. It also cited transportation specialist Raul Lisboa, who claimed that system in its current state does not effectively cover all areas of the favela.

The biggest failure in the use of cable cars isn’t anywhere in Latin America: it’s in London, where the Emirates Air Line across the Thames was constructed in 2012 to much fanfare in the lead-up to the Olympics. Today, the line serves a fraction of the people who took it during the games; the Evening Standard reports that the line only gets four regular commuters per day.

Urban cable cars are relatively new – but even from their short track record, it’s clear that they excel in some situations but fail in others. Let’s hope that the planners take this into account, before the next wave arrives.

Credit for image of Metrocable cars above a Medellín street: Jorge Gobbi, via Flickr, reused under creative commons.

 
 
 
 

Green roofs improve cities – so why don’t all buildings have them?

The green roof at the Kennedy Centre, Washington DC. Image: Getty.

Rooftops covered with grass, vegetable gardens and lush foliage are now a common sight in many cities around the world. More and more private companies and city authorities are investing in green roofs, drawn to their wide-ranging benefits which include savings on energy costs, mitigating the risk from floods, creating habitats for urban wildlife, tackling air pollution and urban heat and even producing food.

A recent report in the UK suggested that the green roof market there is expanding at a rate of 17 per cent each year. The world’s largest rooftop farm will open in Paris in 2020, superseding similar schemes in New York City and Chicago. Stuttgart, in Germany, is thought of as “the green roof capital of Europe”, while Singapore is even installing green roofs on buses.

These increasingly radical urban designs can help cities adapt to the monumental challenges they face, such as access to resources and a lack of green space due to development. But buy-in from city authorities, businesses and other institutions is crucial to ensuring their success – as is research investigating different options to suit the variety of rooftop spaces found in cities.

A growing trend

The UK is relatively new to developing green roofs, and governments and institutions are playing a major role in spreading the practice. London is home to much of the UK’s green roof market, mainly due to forward-thinking policies such as the 2008 London Plan, which paved the way to more than double the area of green roofs in the capital.

Although London has led the way, there are now “living labs” at the Universities of Sheffield and Salford which are helping to establish the precedent elsewhere. The IGNITION project – led by the Greater Manchester Combined Authority – involves the development of a living lab at the University of Salford, with the aim of uncovering ways to convince developers and investors to adopt green roofs.

Ongoing research is showcasing how green roofs can integrate with living walls and sustainable drainage systems on the ground, such as street trees, to better manage water and make the built environment more sustainable.

Research is also demonstrating the social value of green roofs. Doctors are increasingly prescribing time spent gardening outdoors for patients dealiong with anxiety and depression. And research has found that access to even the most basic green spaces can provide a better quality of life for dementia sufferers and help prevent obesity.

An edible roof at Fenway Park, stadium of the Boston Red Sox. Image: Michael Hardman/author provided.

In North America, green roofs have become mainstream, with a wide array of expansive, accessible and food-producing roofs installed in buildings. Again, city leaders and authorities have helped push the movement forward – only recently, San Francisco created a policy requiring new buildings to have green roofs. Toronto has policies dating from the 1990s, encouraging the development of urban farms on rooftops.

These countries also benefit from having newer buildings, which make it easier to install green roofs. Being able to store and distribute water right across the rooftop is crucial to maintaining the plants on any green roof – especially on “edible roofs” which farm fruit and vegetables. And it’s much easier to create this capacity in newer buildings, which can typically hold greater weight, than retro-fit old ones. Having a stronger roof also makes it easier to grow a greater variety of plants, since the soil can be deeper.


The new normal?

For green roofs to become the norm for new developments, there needs to be buy-in from public authorities and private actors. Those responsible for maintaining buildings may have to acquire new skills, such as landscaping, and in some cases volunteers may be needed to help out. Other considerations include installing drainage paths, meeting health and safety requirements and perhaps allowing access for the public, as well as planning restrictions and disruption from regular ativities in and around the buildings during installation.

To convince investors and developers that installing green roofs is worthwhile, economic arguments are still the most important. The term “natural capital” has been developed to explain the economic value of nature; for example, measuring the money saved by installing natural solutions to protect against flood damage, adapt to climate change or help people lead healthier and happier lives.

As the expertise about green roofs grows, official standards have been developed to ensure that they are designed, built and maintained properly, and function well. Improvements in the science and technology underpinning green roof development have also led to new variations on the concept.

For example, “blue roofs” increase the capacity of buildings to hold water over longer periods of time, rather than drain away quickly – crucial in times of heavier rainfall. There are also combinations of green roofs with solar panels, and “brown roofs” which are wilder in nature and maximise biodiversity.

If the trend continues, it could create new jobs and a more vibrant and sustainable local food economy – alongside many other benefits. There are still barriers to overcome, but the evidence so far indicates that green roofs have the potential to transform cities and help them function sustainably long into the future. The success stories need to be studied and replicated elsewhere, to make green, blue, brown and food-producing roofs the norm in cities around the world.

Michael Hardman, Senior Lecturer in Urban Geography, University of Salford and Nick Davies, Research Fellow, University of Salford.

This article is republished from The Conversation under a Creative Commons license. Read the original article.