An autonomous or semi-autonomous vehicle is provided that is capable of braking itself without a driver depressing the brake pedal. The vehicle has a powertrain that includes an engine, a transmission, and a motor with a connected battery to provide regenerative braking capabilities. Friction brakes are provided to apply when necessary, such as when the battery has a high state of charge and further regenerative braking would overcharge the battery. The braking may be activated in response to a sensor detecting a distance to an object in front of the vehicle. A vehicle controller is programmed to automatically control amounts of regenerative braking and friction braking during a braking event based on a comparison between a regenerative torque limit of the powertrain and a desired brake torque over the brake event to safely brake the vehicle during the brake event.