Embodiments of the present invention provide a system comprising: a first controller configured in each of a predetermined plurality of states to generate a torque request signal in order to cause a vehicle to operate in accordance with a target speed value, the system being configured, when the first controller is one of said plurality of states to generate a gear shift limit signal to cause a change in an engine speed at which a transmission controller is permitted to cause a gear downshift, the gear shift limit signal being generated in dependence on at least one traction indicator signal indicative of an amount of estimated traction between the vehicle and a driving surface.