A headway distance maintenance supporting system may include an obstacle detector, a controller configured for determining an operation reaction force to be generated in a driving operation equipment, and an operation reaction force generator for generating the operation reaction force in the driving operation equipment. The controller is configured for controlling the operation reaction force based on the status of a detected obstacle. The operation reaction force comprises a principal operation reaction force and an auxiliary operation reaction force, the auxiliary operation reaction force being no greater than the principal operation reaction force. The controller is configured for generating the auxiliary operation reaction force before a generation of the principal operation reaction force in the driving operation equipment.