In the past few years, the research and development of automated driving have made significant leaps in bringing theory into reality. Forecasts suggest that highly automated vehicles (SAE Level 4) may be on the streets and highways within the next decade. However, current road infrastructure is designed for human drivers, and may not be able to deal with the integration of highly automated vehicles. Therefore, whether to upgrade the infrastructure or not, and how to do so has become a key issue for the deployment of automated vehicles. To cope with the wide range of uncertainties involved, this study uses two of the main driving forces, namely, public expenditure and collaboration level among stakeholders to develop plausible scenarios in order to explore feasible infrastructure requirements for various future scenarios. Two rounds of interviews with manufacturers, road operators and academicians were conducted. The first round aimed at specifying potential requirements and the second one aimed at mapping requirements into the most likely scenarios. Under all plausible scenarios, clear and harmonized road signs and lane markings, High-Definition (HD) maps and Vehicle-to-Infrastructure (V2I) communication technology are found to be key requirements while dedicated lanes can only be considered under the advanced scenario (high public expenditure and high collaboration level among stakeholders). There will be a transition from physical infrastructure to digital infrastructure since the opening of public roads for automated vehicles, but physical infrastructure requirements should never be ignored before this transition is finished. Results provide guidelines to prepare roads for highly automated vehicles.