As a result of pack racing in combination with many cars and inexperienced drivers injuring several drivers and killing the defending Indy 500 winner Dan Wheldon .
Many cars and inexperienced drivers are a major crash occurred 13 laps in .
As a result of pack racing in combination with many cars and inexperienced drivers , a major crash occurred 13 laps in , injuring several drivers and killing the defending Indy 500 winner Dan Wheldon .