So-called ‘real world’ experimentation is an important part of the innovation process, particularly as new technologies, practices, policies or combinations of these emerge as niches. Such ‘real-world’ or in vivo testing of products, technologies and/or processes is thought to generate alternative types of knowledge and data from that produced by way of traditional in vitro laboratory experiments. It is often suggested that in vivo experiments occur in uncontained settings, are less controllable, and present opportunities for unintended experiences or surprises, thereby providing opportunities for second-order learning – changing underlying values and norms. Such real world experiments are increasingly occurring in partnership with public sector actors, including councils and policymakers. In this paper, we use the example of ongoing experimentation with connected and autonomous vehicle (CAV) in two English urban settings, Oxford and Greenwich, to show how the experimental ‘real-world’ is constructed and decided upon by key experimental actors, including some groups (e.g. selected innovators, investors, selected publics) while excluding others (e.g. community groups). We show how public sector interest in these experiments tends to relate to economic development opportunities, identity formation, and regional provenance claims, and is often used to attract inward investment often by way of public-private partnerships. As a result, the spaces of experimentation are often limited to new, high-income neighbourhoods. In this presentation, we consider the types of data and knowledge produced by these urban experiments, and the opportunities and limitations of using these data for decision making.