  When connected and autonomous vehicles (CAVs) are widely used in the future,
we can foresee many essential applications, such as platoon formation and
autonomous police patrolling, which need two CAVs, originally separated in a
mixed traffic flow involving CAVs and human-drive vehicles (HDVs), to quickly
approach each other and then keep a stable car-following mode. The entire
process should not jeopardize surrounding traffic safety and efficiency. The
existing literature has not studied this CAV synchronization control well, and
this study seeks to partially make up this gap.
