A vehicle is described, and includes a drivetrain system including an internal combustion engine and a geartrain, an accessory device, and a route monitoring system. A controller includes an instruction set to monitor operation of the accessory device, and a request to operate the accessory device. When the request to operate the accessory device includes a request to activate the accessory device based upon not exceeding a limit for an operating parameter of the accessory device, the instruction set executes to determine a horizon for the vehicle based upon the projected path for the vehicle, determine a projected road load and a speed constraint based upon the horizon for the vehicle, and determine a projected axle torque command based upon the projected road load. A first routine determines a first command for operating the accessory device that minimizes fuel consumption and meets the projected axle torque command.