Roll-over protection device for vehicles with an expandable rollbar

The motor vehicle occupant roll-over protection system uses a roll bar which is normally held in a lowered rest position against the force of a spring bias by a restraint device, released to allow the roll bar to move into a raised working position via a release element with a sensor-controlled actuator (5). The restraint device has a restraint rod (2) secured to an automobile mounting (3) via a bore (2a) at the release end, receiving a release pin (1) displaced via the sensor-controlled actuator.