Connected and Automated Vehicles (CAVs) offer numerous societal benefits; however, there is still a long way to go before CAVs can be considered reliable and safe. Even when CAV technology has matured, and is more readily available, there will be scenarios that require human intervention such as system failures, situations outside of the AV’s Operational Design Domain (ODD), or to support users. As part of project Endeavour, TRL conducted research on potential human intervention scenarios, which has been considered and referred to as a part of ‘remote operation’. This study sought to understand the current roles of the in-vehicle Safety Driver and Test Assistant during CAV trials and testing to recognise the technical challenges of removing the roles and enabling remote operation. This report includes findings from a literature review and stakeholder engagement and contains: Information on the roles and responsibilities of the in-vehicle Safety Driver and Test Assistant and their remote counterparts Current terminology used in the CAV space, and recommended terms for remote operation Use cases and recommendations to enable safe remote operation A high-level roadmap describing the milestones to enable remote operation in the UK