Cheng was seriously injured in an automobile accident in Santa Clara, California, on November 4, 2008. Cheng had been traveling with his sister, Mae, when their vehicle flipped three times after hitting another car going 60 mph, ultimately ejecting Cheng, who was in the passenger seat, not wearing a seat belt. Mae sustained more minor injuries, as she had been wearing her seat belt. She attended to Cheng, holding his head until two off-duty EMTs approached, fortunate to have had medical equipment with them. They were able to insert a tube into Cheng's throat to help him breathe until the ambulance arrived, to which action doctors later attributed his survival.