An advanced driver-assistance system (ADAS) comprises: a sensor; a behavior planner that performs multi-policy lane change assistance for a vehicle by evaluating multiple scenarios based on an output of the sensor using a cost-based architecture, the cost-based architecture including a Markov decision process (MDP) with a discounted horizon approach applied to pre-chosen open-loop optimistic policies that are time based, wherein the behavior planner uses the MDP for choosing among the pre-chosen open-loop optimistic policies based on respective costs associated with the pre-chosen open-loop optimistic policies, the costs determined by performing a rollout for at least one gap in a fixed time horizon; a motion planner receiving an output of the behavior planner based on the MDP; and a controller receiving an output of the motion planner and determining vehicle dynamics of the vehicle for a next timestep.