Connected and automated vehicles (CAVs), with the capability to exchange information with other CAVs and the infrastructure, open up new opportunities in road traffic systems including the recently introduced concept of lane-free traffic (LFT). In an LFT environment, vehicles move without the need for traditional fixed lanes. It is an emerging research area where many forms of LFT strategies are being investigated that can benefit road capacity optimization, thus reducing traffic congestion and increasing traffic efficiency. LFT strategies can also benefit from current research on non-lane based driving behavior observed in some countries. Thus, this paper overviews the available literature on the current non-lane based driving and future LFT. It also studies the taxonomy used in literature to clearly distinguish the two traffic modes. It details the current developments in LFT research and the underlying technologies. From these developments, the paper provides an overview of currently available approaches for realizing LFT. Finally, it discusses the policy considerations needed for the seamless integration of LFT into the current infrastructure once CAVs become mainstream.