The rapid development of self-driving technology has made self-driving cars come into reality, and some people have already adopted different levels of self-driving technology in real driving practices. With the help of self-driving technology, nowadays people can share and schedule their routes together while driving. However, currently, there are poor supports for such activities, as it demands highly responsiveness, strong consistency guarantees, and low transmission costs. As to support the novel scenario, we developed an edge computing oriented and highly efficient AST-Based lock-free synchronizing and sharing system called Themis on a fundamental itinerary planning model. We optimized the system by adopting partial replication, snapshots of history operations, and compression on consecutive operations strategies, which leave certain calculations at the cloud side, and reduce the amount and size of transmission data in the network. Besides, we have analyzed and proved the correctness of our scheme in detail; examining the significant improvements in performances through experiments.