Why aerial tramways are key to sustainable city transport systems
With urban areas set to boom, cable-car systems are a solution to reduce congestion sustainably
When the historian and critic Lewis Mumford said that adding car lanes to deal with traffic congestion was like loosening your belt to cure obesity, his sardonic advice was rarely heeded. Traffic remains one of those facts of life: dirty, congested, rage-inducing, inevitable.
But picture for a moment the last time you were stuck in traffic – gritting your teeth, trapped in your car – and imagine instead you were sailing above it, getting from A to B in half the time of that miserable drive.
That may soon be a reality for Parisians where, from the south-east of the city through to the hilly suburbs of Créteil, 10,000 passengers a day will be able to use a transit line with a difference: rather than by tram, rail or road, this route will be suspended in the air – via a new 4.5km aerial tramway, the Câble 1 (C1), set to open in 2025.
First proposed in 2008, construction begins this year – connecting Paris’s populous south-east suburbs to the Métro Line 8 station, delivering passengers into the city in just 17 minutes.
Faced with a challenging, hilly environment and much of the region’s ground-level space already accounted for – whether by criss-crossing highways or high-speed rail – Paris decided to build upwards. The cable car route is being built with universal accessibility in mind, and despite the soaring mode of transit, will be boarded at the ground floor level – with no need for stairs, escalators, or elevators.
“We are convinced of the importance of the cable car in an urban environment in comparison with other modes of transportation,” Lucie Coursaget at Atelier Schall, which is designing the Émile-Combes station for the new line. “They’re more economical, eco-friendly, 100% electrical, faster to build – and they’re a pleasing means of urban transport for passengers.”
Unlike the significant investment costs and planning headaches associated with transport infrastructure, building aerial tramways is relatively painless, according to Innovation Seilbahn author Frieder Kremer.
“You don’t have to build roads or dig tunnels, you just need the columns,” he explains. “There’s no requirement for a lot of large infrastructure. And if it doesn’t work, it’s easy to remove and rebuild them.”
Cable cars are generally associated with tourists ascending ski slopes, but aerial tramways have become a buzzy topic of conversation among urban planners in recent years. As well as Paris, projects are underway in Lagos, Nigeria, Dominica in the Caribbean, and Dubai, joining existing networks like those serving Ankara, Turkey, Constantine, Algeria, Caracas, Venezuela, Medellín, Colombia, and La Paz, in Bolivia.
In Medellín and La Paz, these Teleféricos are integrated with the city’s existing public transport networks, and ferry 30,000 and 90,000 passengers daily. The outer reaches of these metropolises – both located in valleys within the Andes – were traditionally difficult for locals to travel to and from. With these aerial transit systems in place, previously disconnected residents were, all of a sudden, able to access the beating heart of their cities – affording much-needed opportunities and allowing them to more easily take part in civic life.
Our cities are set to swell, with some projections forecasting that 68% of the world population will live in cities by 2050 and by 2030, 10 new cities will reach megacity status, where populations topple the 10 million mark. Mobility then becomes an increasingly pressing question.
This growth poses a challenge for cities new and old. As urban sprawl spreads and traditional road or rail networks become pollutant-spewing bottlenecks, commute times become unmanageable and quality of life suffers. Meanwhile, retrofitting or expanding existing infrastructure in older cities often proves complicated and expensive.
“What happens in most cities is that congestion levels establish themselves at equilibrium level, that is, the limit of what’s bearable for people,” says Alexandre Bayen, former director of the Institute of Transportation Studies at the University of Berkeley and co-author of the Oliver Wyman Urban Mobility.
Without proper regulation and careful master planning, these choke points of congestion can spiral out of control. When that happens, cities need to relieve the pressure.
Aerial tramways could be one method to manage this congestion. For example – and this is a back-of-the-envelope calculation, says Bayen – a cable car with one cabin arriving every 10 seconds or so, capable of carrying six people, could roughly mirror a single lane of a regular highway at capacity.
“It’s not a crazy solution for decongestion, as long as it’s for very specific local use,” Bayen says. “They’re one way to do demand management – but you need to find the right origin-destination pairs, where they make sense.”
Kremer discovered that, provided they don’t exceed distances of 7km, aerial tramways are incredibly efficient – anything further, and railways are better. And because they are purely electrical systems, they have the lowest emissions of any other form of mechanised transport. Compared to 1.45g per passenger kilometre in cars, a cable car system measures in at just 0.01g – beating even rail, at 0.02g.
In fact, says Daniel F Morris, clean energy lead at Climate Investment Funds – which is supporting a new aerial tramway in Lagos, Nigeria, connecting Lagos Island to Victoria Island – provided an area’s energy system is relatively clean, cable cars essentially plug right into the grid.
“You don’t have to worry about burning diesel,” he says. “And electrification, I think, is going to be one of the main ways you see the world decarbonising over the next decade or two.”
So if they’re energy-efficient and convenient, why aren’t our skylines crowded with silhouettes of intersecting cable cars? One possible reason is as simple as public perception, adds Kremer. Because most of us think of cable cars as gimmicky forms of transport relegated to scenic holiday views, they’ve rarely been considered a genuinely useful form of urban mobility.
Additionally, while people think cable cars are only useful for crossing obstacles, this isn’t the case, Kremer adds. “If you have two points that should be connected, it doesn’t matter if there are houses underneath or a park or a river. It isn’t a requirement to have physical obstacles in the way.”
Paris’s C1 project, though, may help to change these perceptions.
For a long time, urban cable cars have been associated with problems of altitudes, explains Coursaget. “Cable cars allow much more than serving territories with different altitudes, it allows us to cross rivers, highways, railway lines. Entire neighbourhoods can be opened up in record time, whereas until now, vehicles, buses and tramways were forced to take long, tedious detours.”
While it’s unlikely that our future megacities will resemble a sci-fi skyline of bisecting aerial trams, Bayen notes that these systems could be one effective way to alleviate mobility pressure in urban areas.
“It’s not a patch, but something that can improve connectivity on a surgical basis, as long as there’s economic viability to it,” he said. Like home-working, micro-mobility and the extension of tram and rail networks, cable cars could play an important role in providing a bit of extra breathing space in our progressively crowded cities.
Nearly 400 years since Dutch engineer Adam Wybe built the first functioning cable car on multiple supports in Gdansk, it seems these contraptions may finally lift off – connecting hard-to-reach spots within cities, plugging gaps in existing systems, and at a fraction of the emissions costs.