Överdäckningar – En analys av dagens riskhanteringsproblematik inom denna allt vanligare stadsbyggnadsstrategi

Sammanfattning: The concept of road- and railway overbuilding is an increasingly popular method to use in spatial planning to get rid of physical barriers and create exploitable areas for residential, commercial, and recreational development. Despite the many benefits the method entails, it also brings a lot of problems and challenges regarding risk management with the main issue being how to evaluate and manage risks with extremely low probability and catastrophic consequences. These risks are primarily linked to large scale explosions as a result of transportation of dangerous goods through the tunnel part of the overbuilding which may have disastrous consequences on both the tunnel-users and third-party individuals that are located above. The purpose of this thesis was thus to investigate if there is any applicable science internationally and how the risk management related to overbuilding is conducted in Sweden as well if anything is in need of change. The conclusion implies that the risk management has a lot of room for improvement, in particular when it comes to managing the uncertainty and ambiguity around catastrophic risks, how to enhance the collaboration between actors, and how to facilitate and strengthen the decision-making process.