After cruise control is restored by an accelerating operation, the driver
set speed is changed according to the displacement of the accelerator
pedal. It becomes possible to reduce the driver set speed due to release
of the accelerator pedal, that is, the vehicle can be decelerated by the
engine. Even if the cruise control is restored, the cruise control is not
conducted and the vehicle can be decelerated by the engine if the driver
wants to decelerate the vehicle by the release of the accelerator pedal.