RER, metro and tram networks.

Today, more than 70% of the European population lives in urban areas (there are significant differences between countries – from 50% to 80%); this share is expected to grow to 90% by 2080 (source: EIB). Globally, 55% of the population is urban, i.e. about 4.2 billion people (source: World Bank).

This rapid urbanisation poses many challenges, particularly in terms of land management and, subsequently, mobility networks.

For urban public transport networks (“mass transit” in Anglo-Saxon language), meeting the challenges often means carrying out planned network extensions while maintaining the condition and performance of the existing infrastructure. In other words, network development should not be at the expense of the existing network.

As with the railway networks, the levers of performance lie in :

• Innovation: improving the principles of operation, maintenance and renewal of infrastructures, production methods for construction sites, etc. At the same time, it is a question of ensuring the maintenance in operational condition and then the gradual eradication of equipment inherited from the past that is likely to constitute significant volumes.
• Optimising the interaction between vehicles and infrastructure.
• Staggering construction volumes over time, so as to avoid peaks in workloads that have adverse effects on travellers; such periods of industrial overheating usually involve resource pressures and, consequently, higher unit costs.
• Scenario-building: this is a matter of scenario-building on the effects of the current budgetary framework in the medium and long term, in order to properly inform public policies in this area and to prioritise investments.

The challenges faced by mass transit networks are similar to those faced by national rail networks, but their intensity is multiplied by the complexity inherent in the density of the urban fabric as well as the size of the passenger flows.