Adaptive cruise control systems

An adaptive cruise control device (1) provides a mechanism for re-engaging adaptive cruise control after a vehicle has been brought to a halt automatically. A "blip" on the throttle pedal when the driver wants to proceed is detected by a throttle position sensor (3) and in response, the device (1) instructs the adaptive cruise control system to re-engage. A safety feature inhibits re-engagement if the gap between the vehicle and one in front is below a preset range.