The Architecture, Engineering, and Construction (AEC) industry is undergoing digital transformation to improve project performance and Building Information Modelling (BIM) is helping to achieve this objective. BIM is a comprehensive digital representation of a built facility with great information depth. BIM fosters collaboration across the construction supply chain however the benefits of collaboration are realised only in a relatively small number of BIM-enabled projects. Poor collaboration continues to be one of the major risks affecting BIM-enabled projects with misunderstandings, misinterpretation of data and increased rework. This is especially high in the design phase of construction projects because of the high BIM usage. This research aims to explore the most critical barrier to collaboration in BIM teams in the design phase of infrastructure projects and provide strategies to avoid the barrier in future projects. The most critical barrier in this research is defined as “the main issue that causes the occurrence of problems resulting in undesired outcomes”. For this objective, the case-study method is preferred. Three large infrastructure projects are studied and interviews were conducted with BIM teams to identify the barriers to collaboration in BIM teams. The data collected are analysed by comparing among cases and with literature. Why questions were asked until the main issue that led to the occurrence of problems is found. From the analysis, it is found that lack of guidelines and standards is the most critical barrier to collaboration in BIM teams in the design phase of infrastructure projects. To avoid this problem in future projects, the existing BIM-based design process is improved to work with ISO19650 standards along with strategies to achieve better results. To enable better collaboration in BIM teams, the process is automated using Business Process Management (BPM) software. The proposed strategies are validated with BIM teams for applicability in practice. To conclude, the proposed strategies help in solving the lack of guidelines and standards. It improves the BIM-based design process in infrastructure projects and leads to achieving better collaboration in BIM teams. This research benefits researchers as well as BIM teams. Researchers can validate the proposed strategies in real-life projects and BIM teams can improve their work practices by implementing the proposed strategies.