Today, public urban transportation in the great metropolitan areas of the world have something in common: the need to provide users with different ways of moving. Since users need to move from one place to another in a fast, comfortable manner, many cities have opted for improving their public transportation systems in order to provide a long-term sustainable service capable of adapting to the changing social and geographical conditions of each area. To this end, cities are migrating to multimodal transportation systems in which different mobility technologies coexist, something which gives users access to an entire transit network to reach their destination.

Multimodal transport refers to the transport of goods or passengers using different effectively integrated transportation options. In the specific case of the multimodal transportation of passengers, some of the best known systems in the world are London’s, which brings together buses, metro and ferries, and Hong Kong’s, which interconnects trains, trams, buses, minibuses, taxis and ferries. The Colombian cities of Bogota and Medellin have similar systems.


Transmilenio (Bogota) has a superstructured transportation network which it intends to make the most important public transportation model in the world due not only to its system for integrating several kinds of buses, but also in how it works to be able to meet the needs of its passengers on a daily basis. In order to do so, Transmilenio has laid down a structural backbone combining the Integrated Public Transportation System (IPTS) and the feeder system, a system which aims to integrate in the future with the suburban rail and subway networks. On the other hand, the structuring axis of the Medellin system is formed by several metro lines, to which are, articulated and regular bus lines, an urban cable railway and, recently, a tram line are connected.

The appeal of this type of system lies in the possibility of extending the coverage of the service by adding the individual range of each mode of transportation used in the system. Additionally, it increases its capacity to adapt to the different requirements as regards kinds of trip, frequencies, on-the-spot conditions, etc, whereupon it is possible to maintain the desired device level without incurring cost overruns.

For example, in Medellin, a city of more than three and a half million inhabitants which sits at the bottom of a valley and whose metropolitan area has extended up to the nearby mountains, the urban cable railway lines allow those who live on the sides of the mountains to get to the underground network that criss-crosses the city and to the bus lines. The frequency of passage of cable cars allows a service level to be achieved that is equal to or better than that of buses and at a lower operating cost.

On the other hand, the main challenge faced by multimodal passenger transportation systems is the integration of the different modes of transport. There are 5 key aspects to this integration pertaining to the physical side, the networks, fares, information, and the institutions[1].

  • Physical integration: The stations where users can change means of transport should be designed and sited with ease of access in mind.
  • Network integration: The routes and schedules of each mode of transport should be designed such that they complement and are linked to the other modes in the system.
  • Rate integration: The fare system or payment method (electronic cards) should be unified; alternatively, users who use different modes during their trips should have special fares.
  • Information integration: The information of the entire system should be standardised by means of signage which is complete, useful and easy to look-up and understand.
  • Institutional integration: The different operators and agencies involved in the system should cooperate and coordinate their actions.

Although these five aspects are very important, one is often overlooked: network integration. Beyond the physical component of route design, this integration entails coordinating or synchronizing the different system services in order to ensure that:

  • The capacity of the integrated system is used to the fullest.
  • The demand is adequately met.
  • Users have a pleasant experience in terms of travel time and transfers.

In other words, physical integration should be supplemented with a full integration of the networks in terms of the offer. Going back to the example of Medellin’s multimodal system, having a station where underground passengers can easily take buses is not enough; it is also crucial for the schedules of both modes of transport to overlap so as to avoid very long waits or crowding problems.

However, since all modes of transport differ as to their capacity, speed and demand, planning their interactions can be a highly complex task. In its effort to efficiently meet the emerging needs in the public transportation sector with high-quality, innovative solutions, Goal Systems has developed a set of functionalities for tackling the schedule coordination – or synchronism – problem, thus giving the planners of multimodal passenger systems the tools for modelling these situations and taking them into account to arrive at optimized solutions.

By generating logical schedules by means of these advanced tools, it is possible to configure different kinds of synchronicities (between trunk and feeder lines; between services with common stretches), to create multiple synchronicities for each line, to establish criteria for each connecting point and even to set priorities between the synchronicities which have been defined and with regard to other calculation priorities, always aiming to optimize its solutions.

Medellin’s public transportation system is today a model not only for Latin American countries but also for other countries around the world thanks to its use of a wide range of transport technologies. However, these technologies are faced with the challenge of cooperating among each other in that, given the large influx of passengers to the underground network, buses, cable railways and trams must help to unclog the system by shuttling passengers to the different underground lines and receiving the passengers who get off said lines.

A system of this size must operate with near surgical precision. This is why it is important to use planning tools which are simultaneously flexible and robust to make decisions in order to be able to meet from an operating point of view the needs of the system’s users. Metro de Medellin has taken a first step in this direction with the introduction of GoalBus® and GoalDriver® into its bus lines for a logical scheduling of buses and drivers, which will enable it in the future to fully integrate them with the other lines in the system.

[1] (Booz Allen, 2012) Integrating Australia’s Transport Systems: A Strategy For An Efficient Transport Future. [Online] 2012.


Olga Ossa

Consultores de Optimización en Colombia

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