Where an action has been commenced in respect of the death of or injury to any person occasioned in this state by a motor vehicle and it is alleged that the death or injury was caused or contributed to by another motor vehicle, the identity of which and the owner and the driver thereof cannot be established, the secretary may be added as a defendant on the application of any party and shall be added as a defendant on his own application. The secretary may not be added as a defendant under this section unless physical contact by the unidentified motor vehicle with the plaintiff or with the vehicle occupied by the plaintiff or with such other vehicle which was involved in the accident has been established.