If you ever wonder about the value of personal and car safety rules, you must watch the incident at the end of the NASCAR Daytona July 5th event. It's incredible Austin Dillon walked away.
http://www.nascar.com/en_us/news-media/articles/2015/7/5/last-lap-wreck-daytona-austin-dillon-coke-zero-400.html
The cage and the catch fencing did their jobs.