A vehicle and vehicle system are provided with a controller that is configured to generate output indicative of a road gradient based on at least one of a first estimation, a second estimation and a third estimation. The road gradient is based on the first estimation when a vehicle speed is less than a speed threshold and an input indicative of a longitudinal acceleration is available. The road gradient is based on the second estimation when the vehicle speed is greater than the speed threshold and the longitudinal acceleration is available. The road gradient is based on the third estimation when the longitudinal acceleration is not available.
