  Autonomy and connectivity are considered among the most promising
technologies to improve safety, mobility, fuel and time consumption in
transportation systems. Some of the fuel efficiency benefits of connected and
automated vehicles (CAVs) can be realized through platooning. A platoon is a
virtual train of CAVs that travel together following the platoon head, with
small gaps between them. Vehicles may also reduce travel time by lane changing.
In this paper, we devise an optimal control-based trajectory planning model
that can provide safe and efficient trajectories for the subject vehicle and
can incorporate platooning and lane changing. We embed this trajectory planning
model in a simulation framework to quantify its efficiency benefits as it
relates to fuel consumption and travel time, in a dynamic traffic stream.
Furthermore, we perform extensive numerical experiments to investigate whether,
and the circumstances under which, the vehicles in upstream of the subject
vehicle may also experience second-hand fuel efficiency benefits.
