  Location privacy is critical in vehicular networks, where drivers'
trajectories and personal information can be exposed, allowing adversaries to
launch data and physical attacks that threaten drivers' safety and personal
security. This survey reviews comprehensively different localization
techniques, including widely used ones like sensing infrastructure-based,
optical vision-based, and cellular radio-based localization, and identifies
inadequately addressed location privacy concerns. We classify Location Privacy
Preserving Mechanisms (LPPMs) into user-side, server-side, and
user-server-interface-based, and evaluate their effectiveness. Our analysis
shows that the user-server-interface-based LPPMs have received insufficient
attention in the literature, despite their paramount importance in vehicular
networks. Further, we examine methods for balancing data utility and privacy
protection for existing LPPMs in vehicular networks and highlight emerging
challenges from future upper-layer location privacy attacks, wireless
technologies, and network convergences. By providing insights into the
relationship between localization techniques and location privacy, and
evaluating the effectiveness of different LPPMs, this survey can help inform
the development of future LPPMs in vehicular networks.
