Unlocking multimodal travel in Europe

A paper authored by mainly female experts including Ismini Stroumpou, Project Coordinator of the SESAR EU-funded SIGN-AIR project, has explored how better synchronisation between air and high-speed rail services can unlock multimodal travel across Europe. Developed in the context of SIGN-AIR, the paper's findings will support the project's ongoing efforts to enable single ticketing and smarter data sharing between transport providers, with further case studies planned in airports including Bologna, Istanbul, Brussels, and Athens.

Paper summary: A new era of collaborative travel: Insights from the air-rail connectivity index (ARCI) study

What if airlines and high-speed Rail (HSR) operators were not competitors, but collaborators?

Rather than competing for passengers, high speed railway (HSR) and airlines can work together to create a more efficient, sustainable, and interconnected transport network. The "air-rail connectivity index: A comprehensive study of multimodal journeys" explores this transformative idea, showing how a seamless partnership between air and rail can revolutionise the travel experience. Combined air-rail or rail-air journey must be as easy and comfortable as a connecting flight.

What is the air-rail connectivity index?

Traditionally, airport hub connectivity has focused on air-air connections. ARCI expands this view by quantifying the quantity and quality of air-rail connections, acknowledging the growing integration of multimodal transport systems at major European airports.

How can the air-rail connectivity index help transport operators?

The index is a practical tool for transport operators. It enables them to analyse origin-destination pairs, identify synchronization gaps, and make evidence-based improvements to timetables and connectivity. High ARCI values highlight where multimodal coordination is strong, while lower scores flag opportunities to optimize services.

ARCI also supports strategic modal shift. It helps pinpoint airport-city pairs where high-speed rail can serve as a feasible alternative to short-haul flights-particularly when rail services offer comparable travel times and smoother passenger experiences.

From theory to practice: An illustrative example

The study applied the ARCI methodology to Paris-Charles de Gaulle Airport (CDG), using real operational data from the first week of June 2024.

Key findings include:

• Rail-air and air-rail connections account for over 72% of CDG's total connectivity index, underlining the importance of integrating rail services into the airport hub.

• ARCI values at CDG are, on average, higher than traditional air-air connections, primarily due to more favourable transfer times when rail and air timetables are synchronized.

• Quality matters more than quantity: While some cities like Lille score high due to both frequent and well-aligned services, others like Marseille score lower despite high frequency, due to poor schedule alignment.

More broadly the findings show:

• Hub decongestion - rail integration reduces pressure on airport hubs by diverting short-haul passengers to rail services

• Identify alternative options for short haul flights- HSR could be alternative for the substitution of short-haul trips due to environmentally taxing flights or even due to disruptions.

• Improved connectivity - broader network access: passengers can access regions beyond airports

• Improved passenger experience-through seamless travel and reduced transfer complexity

Next steps

By using ARCI data, SIGN-AIR aims to support transport service providers (TSPs) in designing these combined itineraries and embedding them into agreements. This approach not only promotes smoother travel but also encourages collaboration between airlines and high-speed rail operators, furthering the goal of efficient and sustainable multimodal travel across Europe.

The SIGN-AIR team intends to expand these findings through additional use cases of different size airports . Future work will also explore the extension of the algorithms to identify viable combined itineraries between airlines and on-demand transport options, such as eVTOLs.

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