[Tagging] Turn lane indications vs turn restrictions

[Minh Nguyen]

Vào lúc 05:54 2022-05-30, Tod Fitch đã viết:
> For arm chair mapping using aerial imagery I only add turn lanes, never 
> turn restrictions. For turn restrictions I want to see the signage, so 
> that is in person or using something like Mapillary.

That's a good practice in the U.S. In some states like California, 
U-turns are frequently but not always allowed, but U-turn arrows are 
rarely marked on the pavement. Looking at aerial iamgery, you can be 
more confident of a turn restriction if "ONLY" accompanies the arrow 
marking, but even then, I've seen abutting driveways that contradict 
straight-only markings.

Street-level imagery can also be helpful for replacing "none" with 
explicit "through" or "through;right" indications. For example, Ohio 
religiously posts lane use diagram signs along its state routes, even at 
every abutting business's driveway. These signs always bear each lane's 
indications explicitly, unlike road markings in many cases.

-- 
minh at nguyen.cincinnati.oh.us