1. A method for collaborative location tracking, comprising: grouping a plurality of commuters into a group with at least one server according to a plurality of commuter client devices respectively associated with said plurality of commuters; and tracking with said at least one server said plurality of commuter client devices as said group rather than individually and based on power efficient context-aware location data derived from said plurality of commuter client devices and a generated trip plan in association with data indicative of real-time dynamics so that a power usage of individual commuter client devices among said plurality of commuter client devices is rationally minimized, wherein said generated trip plan is generated by said at least one server.