The challenges society faces in achieving net emission reduction are largely recognised by local and regional authorities. However, traditional planning processes and institutional settings, conventionally characterised by limited transformative capacity, can present problems when navigating these challenges. Experimentation has been heralded as a means of accelerating the sustainable mobility transition, and often involves interventions rolled out at the local level. Yet, experimentation has also been criticised for not facilitating transformation of the magnitude required. With this study, we challenge the assumption that experimentation can lead to an accelerated sustainable mobility transition. The apparent links between experimentation, building transformative capacity and the acceleration of the sustainable mobility transition are analysed by applying a reflexive methodology to the experimentation structure employed by the Mistra SAMS research programme in a living lab setting in Botkyrka, Stockholm, Sweden. The rhetoric behind experimentation, and the roles of the local government and research actors involved in the experiment-based temporary organisational structure, are disentangled. Our analysis centres around the issue of what can be classed as experimentation, the challenges involved in confirming if, to what extent and how experimentation contributes to transformative capacity and the ethical considerations facing the role of the researcher in experimentation activities.