Over the past decade a large number of Field Operational Tests (FOT) have been conducted to test Intelligent Transport Systems (ITS) in real traffic conditions with thousands of drivers. In order to ensure scientifically sound studies a FOT methodology was developed in the FESTA project. Currently we are on the brink of a new series of large scale FOTs, testing automated and autonomous vehicles. A common FOT methodology serves the following purposes: (1) to ensure that a systematic and scientific approach is taken by FOTs, (2) to enable the assessment of the impact of large-scale introduction of ITS on safety, mobility, efficiency and environment, (3) to be able to compare results of different FOTs, and (4) to build a community and facilitate knowledge exchange. FESTA focuses strongly on the drivers of vehicles, and the changes in their behaviour when driving a vehicle that is instrumented with new systems. In FESTA, it is recommended that driving with an ITS is compared with driving without it (the baseline). However, what will be the focus of the new FOTs? And what will be the main research questions these FOTs will address? And what is the baseline? Three types of focus can be distinguished; centred on the user, the vehicle or the context. In this paper we discuss the requirements for a methodology that addresses these three types of focus. We investigate how the current FOT methodology may be adapted or may need to be completely changed. Special attention is given to the type of data that is needed for baselines and for answering research and impact questions (c.f. Barnard et al., 2016). […]