A method for controlling a vehicle system includes obtaining an off-board-based input speed of a vehicle system traveling along a curved segment of a first route. The off-board-based input speed is obtained from data provided by an off-board device disposed off the vehicle system. The method also includes determining a heading of the vehicle system from the data provided by the off-board device and calculating a curvature of the curved segment of the first route using the off-board-based input speed and the heading of the vehicle system while the vehicle system travels along the curved segment of the first route.