Direct quote from Chemical Engineering & News, 02 February 2009, p.13, Cover Story - Materials for the Modern Gladiator by Bethany Halford, Northeast News Bureau.
"BUT INNOVATIONS in safety didn't keep pace with innovations in speed. Between May 2000 and February 2001, crashes claimed the lives of four NASCAR drivers. Nineteen-year-old Adam Petty and 30-year-old Kenny Irwin Jr. had eerily similar fatal accidents just eight weeks apart at the New Hampshire International Speedway. Tony Roper, 35, died during a race at the Texas Motor Speedway. The sport's highest profile fatality was that of its star Dale Earnhardt Sr., after a collision in the last lap of the Daytona 500 in 2001."
A decent article about a few of the materials used in automobile safety advances as learned from the National Association for Stock Car Auto Racing (NASCAR).