There is currently a significant worldwide interest in Connected and Autonomous Vehicles (CAVs), not least for the reason that their realisation and implementation would transform the nature of transportation and provide new impetus for social and economic change. However, the road to support CAVs has not been well prepared, at the risk of leaving potential barriers to CAVs deployment. This paper, therefore, focuses on the gap between current status and future requirements of CAV-compliant road infrastructures, summarizes the possibilities of upgrades, and proposes a three-phase road infrastructure upgrade plan that evolves over time. The first phase is maintenance, followed by a segregated-infrastructure expansion phase leading to phase three which involves the application of simplified standard. The paper is based on an extensive literature review and evidence synthesis and is intended as a stimulus for future study and further debate. For objectiveness, the proposal is general but would need to be refined, when put into practice, to cater for specific implementation contexts.