More than 2 in 5 drivers were driving while stoned when they died in car wrecks in a major Ohio county, a new study says. Coroner records show that nearly 42% of drivers who died in motor vehicle collisions during a six-year period tested positive for THC, researchers are to report Tuesday at a meeting of the American College of Surgeons in Chicago. The deceased drivers had an average THC level of 30.7 ng/mL -- far above the 2 ng/mL to 5 ng/mL legal limit set by other states, researchers said.