## 1 Introduction  
Transportation systems are characterised by many dimensions of complexity. Transportation networks are transnational and geographically dispersed, requiring the involvement of many public and private transportation operators, infrastructure, and facility-management companies. Transportation is multimodal and intermodal, combining different travel modes that vary in scale, operational flexibility, and operational complexity. The international dimension also brings differences in compliance with local regulations, which are handled differently by local authorities, as well as language challenges.  
Ideally, travellers would access the entire transportation system as a \"single service\" that supports trip planning and travel. Several projects have been initiated in Europe to integrate these different ecosystems and bring open platforms into the everyday lives of travellers. Many of them are supported and funded by the European Commission through Interreg and the Framework Programmes. A common goal of these efforts is data integration between the different public transport subsystems and the promotion of environmentally friendly and sustainable travel with multimodal public or zero-emission transport.  
In every trip, travellers encounter the physical infrastructure that enables transportation, both in the planning phase and during the actual trip. In addition to linear infrastructures such as roads and railroads, infrastructures can be simple, such as on-streetbicycle racks and parking lots; or complex, such as airports, major train stations, and ports. Physical infrastructures significantly influence travel. Their influence is especially important when travellers are unfamiliar with the places that are part of their trip, such as the locations where transportation modes are changed. Physical infrastructures also influence travel for people with disabilities. Therefore, the data-integration platforms, public transit models, and trip-planning software applications mentioned above should include physical-infrastructure models. However, data collection and integration into transportation models requires additional effort, and access to and recoding of available information.  
On the other hand, the construction industry, which creates the physical infrastructure for transportation, is also seeking to digitise construction planning and processes. Although digitisation in construction lags behind other industries [1], there are many academic efforts to introduce information and communication technology (ICT) in the industry [2]. Various aspects and barriers that contribute to this lagging are being explored, such as technological and interoperability issues, methodological and organisational challenges, and cultural and social aspects of technology adoption. Contextual requirements and interoperability issues are particularly relevant to this study. The development of transportation models and the standardisation of data exchange, in both the construction and transportation sectors, provide the framework and define the information requirements for the construction industry. In this way, the transport sector acts as a driving force and demand for the digitisation of the construction industry.  
The paper presents a concept for the integration of transportation information models used by journey planners, and platforms with information models of built transportation infrastructure as a result of the application of building information modelling (BIM). In the following sections, we explore how existing transportation systems can benefit from this integration.  
Our research questions are therefore:  
1. How can building information models be incorporated into transportation information models?
2. What technological solutions can be used to support information exchange between the building and transportation sectors?