Current road infrastructure is designed for human drivers, and may be unable to deal with the integration of highly automated vehicles. The aim of this paper is to explore potential infrastructure requirements for automated driving SAE Level 4. To cope with the wide range of uncertainties involved, a scenario-based approach was used to define two plausible future scenarios. Subsequently, two rounds of interviews with manufacturers, road operators, and academicians were conducted. The first round aimed at specifying potential requirements while the second round aimed at mapping these requirements into the scenarios. The main finding is that under both plausible scenarios, clear and harmonized road signs and lane markings, High-definition maps and vehicle-to-infrastructure communication technology are key requirements while dedicated lanes can only be considered under the advanced scenario. Additionally, the results show that a transition from physical infrastructure to digital infrastructure will happen after roadside wireless technology is available.