Your variability point extends beyond just left turns. Routes with lots of lights or that cross train tracks have extra variability. If I'm leaving with barely

Your variability point extends beyond just left turns. Routes with lots of lights or that cross train tracks have extra variability. If I'm leaving with barely enough time I want directions that have low time variance since I cannot afford to be on the wrong side of the distribution. Other times I'm willing to risk some variance for a shorter expected time.