A vehicle is provided with: a main vehicle body having an attachment portion to which a towed vehicle can be attached, and a first onboard unit and a second onboard unit attached to the main vehicle body, the first onboard unit and the second onboard unit being installed so as to be capable of communicating with a roadside device. The first onboard unit has type information relating to the type of the main vehicle body, and is provided at a position at which communication with the roadside device is possible both when the towed vehicle is attached to the attachment portion and when the towed vehicle is not attached to the attachment portion. The second onboard unit is provided at a position at which communication with the roadside device is possible when the towed vehicle is not attached to the attachment portion and at which communication with the roadside device is not possible when the towed vehicle is attached to the attachment portion.