Unlike alcohol, California doesn’t have a legal limit for drugged driving. So it’s up to drug recognition experts. But how do they evaluate someone they think may be under the influence? Hear the last story in KPBS’s five-part series: “High Hopes: California's Pot Experiment.” Plus, Jingle Bells, Silent Night and Joy to the World. Find out how these songs are helping veterans with lung disease get better. And meet Jonathan Hunt, librarian for the San Diego County Office of Education. He’s going to share his top 12 kids books of 2019. He says younger audiences have become more willing to address difficult topics.