Automated vehicles exist on a spectrum of automation. The lower end of the spectrum requires the driver to be in complete control of the driving. At the middle of the spectrum, the driver is required to be in control of specific aspects of the driving. As we move towards the end of the spectrum, the driver is in the role of a passenger, with the vehicle functioning as a robotaxi. Driver Monitoring Systems (DMS) are a vehicle system that monitors the driver through various sensors. They are used for the following reasons i) to enhance safety by detecting driver states that need support for safe driving ii) to aid transfer of driving control back to the driver, if needed in a highly automated vehicle iii) to increase user experience by providing measures to enhance DMS detected driver wellbeing and comfort. With the advancements in its development, DMS will soon be able to detect driver states such as fatigue, distraction, various emotional states and potentially even conditions such as early stage cognitive decline. The functionality of a DMS and the motive behind its use, varies across the spectrum of vehicle automation. This PhD takes on a holistic approach to exploring DMS as we progress towards its safe implementation in future vehicles, achieved through the following research questions: i) How do DMS types vary across the spectrum of vehicle automation? ii) How does the public perceive and understand DMS? iii) How do transport policymakers expect the working of DMS to be? iv) How does the above align with DMS manufacturer’s implementation?