An ambulance cot frame securing system for a patient transport vehicle which includes a floor frame adapted to be secured to a floor of the patient transport vehicle. The floor frame has at a first end thereof a fixed angled restaint inclined upwardly and in a direction toward a second end of the floor frame to define an overhang spaced upwardly from the floor frame so as to provide a gap into which is adapted to be received a first part of the cot frame. The floor frame additionally has a releasable latch mechanism adapted to be releasably coupled to a second part of the cot frame so as to hold the cot frame in a fixed lengthwise location relative to the floor frame. The securement system additionally has a self-activating locking mechanism activatable in response to a sudden burst of either acceleration or deceleration of the patient transport vehicle to additionally securely lock the first part of the cot frame in a fixed position relative to the patient transport vehicle.