Here are some nice photos of Run Flat Tires which shows a good comparison against the normal tires. Even when punctured, Run Flat Tires can resist the effects of deflation. Run Flat Tires are more reinforced and stiffer than the normal tires, which gives the driver the luxury to drive at least 100 miles with a flat tire, in reduced speed. The normal tire is on the left side of the photos, Run Flat Tire is on the right side. Spot the difference.
Source: 1addicts