That means it can be driven for a limited time, even after air pressure loss. In other words, when air pressure leaves the tire due to a puncture or some other damage, the tire can still perform for 50 miles up to the speed of 50 mph. This makes sure the vehicle will not be stranded on the side of the road. Instead, the structure withstands the weight of the vehicle and its passengers, allowing the vehicle to safely arrive at a nearby location. Run flat tires should not be mounted on the same vehicle together with regular tires, due to their heavier construction.