Maddox Jolie-Pitt, the nine-year-old eldest son of actors Brad Pitt and Angelina Jolie, celebrated his birthday recently at Go Kart World in Carson, California (via People). While scores of kids like Maddox enjoy a fun and safe experience on the motorized karts every day around the nation, the vehicles can be dangerous, as the death of nine-year-old Taybor L. Duncan at Grand Junction Motor Speedway demonstrates. Duncan was participating in a go-kart competition when her kart flipped multiple times after hitting the trailer of a maintenance vehicle that was on the track (via The Denver Post). "We don't know if she didn't see it, but she clipped the back corner of the trailer and flipped the go-kart," says Sally Weese, a spokeswoman for the Mesa County Sheriff's Office, adding that no one else was harmed in the event, which was held during the CKJC JR Kart Club race. The girl was wearing protective gear, including a helmet, seat belt, and protective chest plate, notes 7News. Duncan, whose nickname was "Tay Tay," began racing in 2008 and enjoyed "going fast" and "having fun" on the karts, but also "being safe," according to a posting on the karting club's website cited by the television station.