Nearly one-fifth of teens have driven while high on marijuana, according to a study conducted by Liberty Mutual Insurance and Students Against Destructive Decisions. “While parents seem to have done a fairly thorough job instilling in our kids the importance of not driving after drinking alcohol—only 13 percent of teens have driven while under the influence of alcohol—apparently we’ve been failing to relay the dangers of driving after smoking pot,” writes Kristin Varela of Cars.com. (Chicago Tribune)