I've seen spectacular wrecks in races at Talladega Superspeedway and Daytona International Speedway, where 20-30+ cars are involved. Such massive wrecks are known as "the Big Ones." They are very common at both tracks, especially the former.

Interestingly, the crashes that are most survivable are the ones that look the worst, such as the violent flips and barrel-rolls after the car goes airborne and upside-down. Some of these wrecks may sometimes cause the car to catch fire. But the ones that are truly the worst are the ones that go head on into the wall. They may not look that bad, but they can be fatal. That is exactly what happened to Dale Earnhardt in his fatal crash on the final lap of the 2001 Daytona 500. He got loose, and massively decelerated from 180+ mph, cutting across traffic at a sharp angle, hitting the wall head on. No fire, no catapulting into the air, and he died instantly of a type of injury known as a basilar skull fracture.

Seven years later, Michael McDowell survives a horrifying crash while using the newly-engineered Car of Tomorrow. He gets loose, hits the wall, catches fire, and barrel-rolls several times. The safety features of the new car, the SAFER barrier (Steel and Foam Energy Reduction), and the HANS device (Head and Neck Support) protected him. The crash was striking similar to the fatal crash of Gordon Smiley, an Indy driver, and was about 10 mph faster than Dale Earnhardt's fatal accident.