After crash that killed 6 teens, NTSB chief says people underestimate marijuana’s impact on drivers

A horrific crash that killed six high school girls in Oklahoma two years ago has the head of the U.S. National Transportation Safety Board urging parents to warn teenagers about the risk of driving after using marijuana

​A horrific crash that killed six high school girls in Oklahoma two years ago has the head of the U.S. National Transportation Safety Board urging parents to warn teenagers about the risk of driving after using marijuana A horrific crash that killed six high school girls in Oklahoma two years ago has the head of the U.S. National Transportation Safety Board urging parents to warn teenagers about the risk of driving after using marijuana US