  When the traffic stream is extremely congested and surrounding vehicles are
not cooperative, the mandatory lane changing can be significantly difficult. In
this work, we propose an interactive trajectory planner, which will firstly
attempt to change lanes as long as safety is ensured. Based on receding horizon
planning, the ego vehicle can abort or continue changing lanes according to
surrounding vehicles' reactions. We demonstrate the performance of our planner
in extensive simulations with eight surrounding vehicles, initial velocity
ranging from 0.5 to 5 meters per second, and bumper to bumper gap ranging from
4 to 10 meters. The ego vehicle with our planner can change lanes safely and
smoothly. The computation time of the planner at every step is within 10
milliseconds in most cases on a laptop with 1.8GHz Intel Core i7-10610U.
