The tire's sidewalls are capable of supporting the weight of the vehicle and passengers after a puncture or cut causes the air pressure to leave the tire. When this happens, the model can be driven for 50 miles up to the speed of 50 mph, which allows the driver to arrive safely at their destination and not be stranded on the side of the road. Run flat tires are made for vehicle's that do not have space for a spare tire and due to their heavier construction they cannot be mixed with regular radial tires.