UPS figured out decades ago that left turns in urban settings are usually suboptimal. Why don't nav applications allow drivers to avoid left turns except at intersections with left arrows?
It’s apparently used to apply an additional routing penalty for “difficult intersections”, assigned by map editors, which provides a robust way to avoid these situations, including difficult left turns: https://www.reddit.com/r/waze/comments/ffypgb/avoid_difficul...