I recently was talking about protected left-hand turn patterns and remembered a trip to Arizona in the early 2000s. I remember my parents being initially cautio

I recently was talking about protected left-hand turn patterns and remembered a trip to Arizona in the early 2000s. I remember my parents being initially cautious but quickly thrilled about protected left-hand turns coming after yellow lights and before red lights. It seems like it ought to reduce congestion and accidents. So I started looking into it, and I found that that isn't even an all-Arizona thing. Municipalities decide their own light patterns. Some places even change the pattern from morning to night coincide with commutes. I never did figure out if there were any safety or congestion benefits. I'm still shocked that that level of localism doesn't cause chaos.