Complex sentence: He went on to become an Indy Racing League driver before a testing accident paralyzed him and ended his driving career, later starting Sam Schmidt Motorsports, a successful Firestone Indy Lights championship-winning team, and the Sam Schmidt Paralysis Foundation.
Split into simpler sentences: He went on to become an Indy Racing League driver before a testing accident paralyzed him and ended his driving career. He later starting Sam Schmidt Motorsports, a successful Firestone Indy Lights championship-winning team, and the Sam Schmidt Paralysis Foundation.