  In preparing for connected and autonomous vehicles (CAVs), a worrisome aspect
is the transition era which will be characterized by mixed traffic (where CAVs
and human-driven vehicles (HDVs) share the roadway). Consistent with
expectations that CAVs will improve road safety, on-road CAVs may adopt rather
conservative control policies, and this will likely cause HDVs to unduly
exploit CAV conservativeness by driving in ways that imperil safety. A context
of this situation is lane-changing by the CAV. Without cooperation from other
vehicles in the traffic stream, it can be extremely unsafe for the CAV to
change lanes under dense, high-speed traffic conditions. The cooperation of
neighboring vehicles is indispensable. To address this issue, this paper
develops a control framework where connected HDVs and CAV can cooperate to
facilitate safe and efficient lane changing by the CAV. Throughout the
lane-change process, the safety of not only the CAV but also of all neighboring
vehicles, is ensured through a collision avoidance mechanism in the control
framework. The overall traffic flow efficiency is analyzed in terms of the
ambient level of CHDV-CAV cooperation. The analysis outcomes are including the
CAVs lane-change feasibility, the overall duration of the lane change. Lane
change is a major source of traffic disturbance at multi-lane highways that
impair their traffic flow efficiency. In providing a control framework for lane
change in mixed traffic, this study shows how CHDV-CAV cooperation could help
enhancing system efficiency.
