After the loss of air pressure, the tire supports the weight of the vehicle and the passengers for 50 miles and up to 50 mph, thanks to the special reinforced run flat tires. In the case of air pressure loss the driver can safely arrive at a destination to repair or change the tire. This means the driver will not be stranded on the side of the road with a flat tire. Since run flat tires are heavier, they should not be mixed with regular radial tires.