High-capacity, segregated, and high-frequency public transport systems (i.e., Mass Rapid Transit or MRT) continue to proliferate in urban areas, with approximately 26% of Europe’s metro systems being constructed since 2000 according to the International Association of Public Transport. MRT systems facilitate cities’ efforts to transition to sustainable mobility by boosting the mode share of sustainable transport modes and reducing private vehicle use.

However, MRT projects do not always succeed in facilitating sustainable mobility transitions. Viable project plans can fail to pass appraisal processes; projects that pass appraisal and receive planning approval often experience issues during project development that put a challenging cost burden on governments and private investors; furthermore, even projects that are successfully delivered often fail to meet ridership and mode shift targets. In light of these shortfalls, we examined a number of MRT schemes across Europe to identify effective practices and common pitfalls when delivering MRT infrastructure.

Overcoming inadequate appraisal frameworks

The UK, like many other countries, utilises cost-benefit analysis (CBA) as part of the transport project appraisal process. CBA focuses on monetised benefits, and most transport project appraisals heavily weight the value of time (i.e., time savings) over other monetizable benefits. According to an academic article by Robin Hickman and Marco Dean from University College London, this appraisal method tends to favour road projects because public transport projects’ extensive environmental and social benefits are either not monetised or discounted relative to time savings. Such appraisal practices can make public transport schemes difficult to justify in terms of value for money.

For example, according to a Crossrail report on the appraisal of Crossrail (Elizabeth Line), the project initially only achieved a benefit-cost ratio (BCR) of 1.8 (i.e., “medium” value for money) despite its potential to deliver considerable benefits. In the face of this disappointing BCR, the Greater London Authority (GLA) developed a new approach to transport appraisal called “wider economic benefits, which is now used in the UK and many other countries. The approach argues that adding transport capacity unlocks employment growth, triggering development that would not have happened without the new public transport infrastructure. Incorporating these benefits boosted the BCR for Crossrail to 3.09 or “high” value for money according to a House of Commons briefing paper on the project. The Crossrail case illustrates the importance of challenging and updating existing appraisal techniques to demonstrate the true value of public transport projects.

Governance regimes and project risk

Most of the projects we analysed incurred some amount of delays and, consequently, cost increases. Reasons for this range from engineering challenges like signalling unification to unexpected archaeological discoveries. Despite this, we found that the origins of delays and cost overruns often stem from the contracts, institutional arrangements and other structures that govern the implementation of MRT projects. 

Contractual adherence to guidelines set by a project financier became an issue for the Marmaray project, a regional metro line connecting the European and Asian sides of Istanbul. As illustrated in a report produced by NYU researchers on transport projects in Istanbul, The Japan Bank for International Cooperation, which helped finance the Marmaray project, required the use of the FDIC Silver Book, an engineering, procurement and construction contract guide. Due to a lack of experience with the Silver Book, stakeholders were delayed driving up costs.

This case and numerous others illustrate the importance of avoiding restrictive financing arrangements and instead designing a project governance regime that synergises with local conditions and addresses the complexities that emerge during the design and construction of MRT infrastructure.

The power of networks

We found that MRT projects implemented in cities that already benefit from a widespread public transport network experienced strong ridership increases that often exceed estimates. Conversely, cities without a robust existing network can struggle to attract riders to new infrastructure.

The Metro M3 ring line in Copenhagen opened in late 2019 connected key city centre destinations and major existing public transport hubs like Østerport, Nørrebro, and Copenhagen Central stations which provide regional, national, and international rail services. The M3 exceeded ridership estimates by 36% with 12 million riders in the first 15 weeks of operation according to data published by Copenhagen Metro (Metroselskabet). Less than a year after M3 opened, pandemic restrictions collapsed ridership in early 2020 for the entire public transport network, and passenger numbers only fully recovered in the last 12 months according to Copenhagen Metro and Statistics Denmark.

Meanwhile in Rome, while the new Metro Line C (partially opened in 2015) provides a modern service, the city’s metro network is still limited relative to its size. Furthermore, numerous recent reports and articles have highlighted that Rome’s existing public transport system suffers from insufficient services and a chaotic governance structure. These factors meant that despite the partial opening of Line C, public transport ridership in Rome allegedly declined by approximately 25% between 2015 and 2019 and private vehicles now account for 50% of all trips according to publicly available data.

These contrasting examples demonstrate that an existing efficient public transport network can significantly influence project success. MRT Projects that plug important “mobility gaps” in cities that already have a robust network tend to create a large positive impact. On the other hand, new MRT infrastructure is not a silver bullet for addressing poor ridership in cities with an unattractive public transport offering; resolving wider network deficiencies through infrastructure improvements in addition to building new infrastructure is necessary to reap the full benefits of MRT systems in these environments.

Challenges project development processes

These lessons demonstrate that inadequate appraisal frameworks, poorly designed project governance regimes, and a failure to consider wider network contexts often drive cost overruns and other undesirable project outcomes (e.g., low ridership) for MRT schemes. We consider it essential to challenge project development processes that too often fail to efficiently deliver MRT schemes. In our view, early collaboration between the public sector and specialised private sector expertise can help governments apply lessons learnt to avoid common pitfalls, draw on international best practice and ultimately deliver new MRT infrastructure that facilitates the transition to sustainable mobility in a cost-effective manner.