A method includes forming a first schedule for a first vehicle to travel in a transportation network. The first schedule includes a first arrival time of the first vehicle at a scheduled location. The method also includes receiving a first trip plan for the first vehicle from an energy management system. The first trip plan is based on the first schedule and designates at least one of tractive efforts or braking efforts to be provided by the first vehicle to reduce at least one of an amount of energy consumed by the first vehicle or an amount of emissions generated by the first vehicle when the first vehicle travels through the transportation network to the scheduled location. The method further includes determining whether to modify the first schedule to avoid interfering with movement of one or more other vehicles by examining the trip plan for the first vehicle.