A system includes an acquisition unit that acquires an operation amount or a duration count, and a switching unit that switches a driving state. The switching unit switches the driving state to the cooperative driving state when the operation amount is equal to or greater than an intervention threshold and less than a start threshold or the duration count is equal to or greater than a first threshold and less than a second threshold during the autonomous driving state, switches the driving state to the autonomous driving state when the operation amount is less than the intervention threshold or the duration count is less than the first threshold during the cooperative driving state, and switches the driving state to the manual driving state when the operation amount is equal to or greater than the start threshold or the duration count is equal to or greater than the second threshold.