Cities worldwide, including Stockholm, are attracting more residents, making providing public transport services challenging and passenger overcrowding a new norm. Crowding negatively affects passengers' travel experience and the operations of the public transport system. So far, little attention has been given to how the new urban developments contribute to public transport crowding. Empirical knowledge of how new residents impact on the crowding conditions in the system can guide tailored policy initiatives such as infrastructure investments and calibration of the ex-ante public transport models (macroscopic network assignment models).

The CAPA-CITY project utilizes the large-scale Access-kort data available for most of the trips in Region Stockholm. The project's primary goal is to identify the network-wide public transport crowding implications and capacity needs of new urban development areas. The research team focused on capturing the non-local effects of urban developments that have consequences for the crowding experienced, not limited to those experienced by travelers originating from or destined to these areas. To this end, the team proposes a workflow for supporting planners and policy-makers in assessing the crowding implications and capacity requirements induced by urban developments.

We demonstrate the proposed workflow for various newly developed areas in Region Stockholm, accounting for diverse characteristics in terms of size, type (e.g., residential/business/mixed), location (e.g., central/peripheral), proximity to a high-capacity public transportation connection and in terms of socioeconomic characteristics. To this end, we perform a before-after analysis utilizing Access-kort data accounting for a sufficient time period before the urban development and during/after the completion of the construction phase.

Last, it is important to mention that the development and monitoring of the public transport system of Region Stockholm should rely on the best empirical evidence available to support evidence-based decision-making and set the right priorities. The proposed workflow in the CAPA-CITY project can assist in more efficient public transport planning in relation to new urban developments, supporting the initial planning from planners in Region Stockholm.