A vehicle navigation system is composed of first and second recording devices, first and second execution module, and an install module. The first and second recording devices respectively stores therein first and second computer programs used for vehicle navigation. The first and second execution module respectively executes the first and second computer programs. The install module transfers data stored in the second recording device, including the second computer program, to the first recording device. The install module is allowed to operate during operation of the second execution module, while the first execution module is prohibited from operating during operation of the second execution module.