At the turn of the century, the Colombian city of Medellín had the reputation of being an exceptionally violent and dangerous place and a global centre of drug crime. There were major problems of social exclusion: the residents of the hillside barrios that sat above the city were not well served by public transport. Within the wider context of urban integration, the city introduced the Metrocable, a cable car which connected the people of the barrios with the city centre in the valley below.
The city of Medellín, the second largest in Colombia, “is located in the Aburrá Valley in the central Andes, 1,479 metres above sea level”. It has its centre in the valley, with a number of barrios – informal settlements – on the hills that surround it. In the early 2000s, the only ways for the residents of the barrios to go into town was to walk or to catch one of the infrequent, unreliable buses. “Insufficient transport, low presence of state institutions and lack of public services inhibited development and employment opportunities for residents.” 
These problems contributed to the physical and social marginalisation of these districts, resulting in poor access to the labour market, an increasingly serious lack of opportunities as well as high rates of crime and violence. “‘It was impossible to reach the centre of town; we were stuck here.’”  Medellín was also the centre of operations of the drug baron Pablo Escobar.
The solution for such problems of steep access has generally been either a funicular railway or a cable car. In 2004, the first Metrocable cable car was built in Medellín. “By integrating the design of the system with other forms of mass transit and improving access for pedestrians, the city’s Metrocable system has helped connect low-income residents to their city and put urban mobility at the heart of equity.” 
The overarching goal was social inclusion and improving the quality of life in the barrios. The more specific objective of the Metrocable was to connect three of the barrios to Medellín’s main metropolitan public transport system in the centre, and to increase the Metro’s levels of usage.
The publicly-owned Metro de Medellín company and the city authorities worked closely together to implement the project. There are currently three aerial cable-car lines in operation. The cost of the first line was close to USD24 million and the second to USD47 million.
The public impact
The first line to be built was Metrocable line K, to the Santo Domingo Savio neighbourhood, which reaches around 230,000 inhabitants in 12 localities and links northeastern Medellín with the city centre. Metrocable Route J serves 315,000 inhabitants in 37 districts.
The Metrocable has halved the average travel time from the barrios to the centre, from roughly two hours to one. Its integration with Medellín’s main public transport system has increased the comfort of passengers and reduced the cost and duration of their journeys.
The area around the first cable car line became a prototype for social interventions in some of the poorest areas of the city, as part of the drive to social inclusion. The Proyecto Urbano Integral [Integrated Urban Project] (PUI), the urban integration project which addressed a context within which the Metrocable operated, won The Veronica Rudge Green Prize in Urban Design, “the foremost award recognising achievement in this field”. 
What did and didn't work
Stakeholder Engagement Strong
The project involved a number of stakeholders who were committed to its logistical and socioeconomic objectives:
- The city authorities.
- The publicly-owned Metro de Medellín company.
- The inhabitants of the barrios who used the cable cars.
- The participants in the PUI, who “helped to select the location of the stations, with the objective of complementing and amplifying the positive impact of the Metrocable”. 
Political Commitment Strong
The year 2000 was an electoral year, and Metro de Medellín presented the cable car project to the mayoral candidates. Whilst most rejected it, the successful candidate, Luis Pérez, the mayor from 2001 to 2003, “happened to be as keen an enthusiast of cable-cars as the newly-appointed head of Metro de Medellín. Pérez immediately committed the city authorities; three years later it was in operation”. 
The project was equally strongly supported by Sergio Fajardo, the mayor of Medellín from 2003 to 2007. He was committed to the Metrocable in itself and as part of the wider PUI project: “under the leadership of Mayor Sergio Fajardo in 2004, the city bet on a public policy focused on reducing the profound social debts that had accumulated over decades, in addition to the legacy of violence”.  The project was financed jointly by the municipality and the publicly-owned Metro de Medellín.
Public Confidence Good
The project has the enthusiastic participation of the public, judged by the number of passenger journeys and the fact that the government actively involved the citizens who were affected by the project in its planning and implementation.
In 2004, when the first line was opened, it was widely perceived as a success. “It also inspired many other Latin American cities with similar topography and socioeconomic dynamics to explore aerial cable cars as mobility solutions. La Paz-El Alto, Bolivia; Caracas, Venezuela; Rio de Janeiro, Brazil; and Manizales, Colombia have all built cable car systems that help connect peripheral communities to the urban core.” 
Clear Objectives Strong
The objectives were achieved as envisioned and did not alter during the project. They were clear, although they were a synthesis of improving transport links through the Metrocable, and setting it in the context of urban regeneration and social inclusion. “A coherent and energetic policy of integrating the cable-car systems into the urban fabric through [PUI] was developed, centred around transport projects but aiming for urban improvement through a combined strategy on mobility, environment, housing and public space, and the goal of creating of new dynamic centres in previously atrophied sectors.” 
Cable cars had been a technically well-established form of transport for nearly a century, “dating back to 1914 in Bern, Switzerland. The cable car systems of the past were typically low capacity and designed to transport tourists, particularly in ski towns”.  However, Medellín provided a radically different socioeconomic context. “When Medellín became the first city to implement aerial cable cars as a public transport system, it did so with equitable urban mobility and the city’s unique geography in mind. Cable cars, the city realised, would be well suited to serving the dense informal settlements on the city’s mountainous periphery.”
As the project was in this sense the first of its kind, it required evidence-gathering and technical analysis before being implemented. “In the late 1990s various studies and technical consultations were undertaken by Metro1. In the late 1990s various studies and technical consultations were undertaken by Metro de Medellín.” 
The impact of the studies and consultations was that “by 2000 it had become a technically and financially feasible project”. While the success of Line K has not been in doubt, there has been more sceptical analysis of Line J.
The city administration had to address issues such as:
- The potential environmental impacts, which were considered in the planning stages, including benefits such as reducing emissions of greenhouse gases, and air quality has been improved.
- The risk of investing in a project of this size and novelty. During implementation, the authorities faced problems of cost overruns.
- The likelihood of achieving benefits such as “small-scale economic activity … In the second system, Line J, where the stations are less well articulated to urban morphology and street patterns [compared to Line K, such] benefits are still less evident". 
- “Whilst the first line has been highly successful and runs at full capacity (approximately 30,000 passengers per day), the impact of the second cable car line suggests that, to be economically and socially significant, cable car systems require specific minimum conditions in terms of urban morphology and population density, as well as careful integration with the existing mass public transit network.” 
The efficiency with which the Metrocable was implemented reveals that the delivery context was well understood and effectively managed. “The speed with which the cable-car system was implemented and its articulation to the city's overall transport system owes much to the city’s institutional and governance structure. The publicly-owned Metro de Medellín company and the city authorities worked closely together in both a technical and financial sense. The Metro de Medellín company lies nominally in the hands of central government. There were issues between the parties involved but in light of the overall goal, these were effectively resolved.” 
The measurement of the Metrocable’s impact has taken two main forms:
- The use of the system made by ordinary users, in terms of the number of passenger journeys and journey times (e.g., 3,000 journeys per day on Line K).
- The environmental impact: to estimate this, Metro de Medellín prepared a Project Design Document, which proposed a baseline and a methodology to gauge environmental impact.
The degree of social inclusion is far more difficult to measure quantitatively, as is the integration of the Metrocable journeys with the city centre transport system, such as the Metro.
The authorities worked closely together in implementation of the projects. There were coordination issues between the city authorities and the company but these were gradually resolved.
Metro de Medellín company and the city authorities worked closely together in both a technical and financial sense. “Although this has led to periods of tension over technical matters (for example over bus feeder routes and a complementary rapid bus transit system currently under construction), these have generally been resolved on the basis of the efficiency of the Metro and a shared commitment to urban improvement.” 
The participation of the cable car passengers, and the residents of the barrios generally, has been encouraged by successive mayors. There has also been a shared sense of purpose with the architects, urban planners and others involved in the broader PUI project.
Aerial cable-car systems for public transport in low-income urban areas: lessons from Medellin, Colombia, Peter Brand, Julio Dávila, 4-8 July 2011, World Planning Schools Congress, Perth, Western Australia