ISO 16992:2006 describes spare unit substitutive equipment (SUSE) for passenger car tyres. This equipment is designed to allow the user to continue on the journey (with or without a stop) in a reasonably safe manner.ISO 16992:2006 only aims to qualify the performance of extended mobility systems. It details specifications only for extended mobility systems suitable to permit the extended mobility of the vehicle. Other types of SUSE are described in the informative annexes.ISO 16992:2006 applies from the moment the extended mobility system becomes effective, and the driver has continued control of the vehicle (in speed and direction) in order to attempt to reach an appropriate place for servicing.ISO 16992:2006 does not coverthe vehicle thus equipped;the tyre while operating in inflated mode;the characteristics of the pressure survey device and of the warning function relative to the inflated mode or to the partially deflated mode due to slow pressure losses;the transitory phase, if any, before the equipment becomes effective;the inspection, assessment, and the servicing of the extended mobility system after it has been activated in flat tyre running mode.ISO 16992:2006 includesthe description of the various types of SUSE;the description and performance levels of complete extended mobility systems.