The reinforced internal structure prevents the tire from deflating when losing air pressure. The tire offers a limited, temporary performance, which means that it can still be driven on for 50 miles within the speed limit of 50 mph. In other words, the vehicle won't be stranded on the side of the road, but instead, it can be driven safely to a nearby location where the tire can be repaired or replaced. Run flat tires should not be used on the same vehicle at the same time with regular tires due to their different construction.