In Washington state unprotected lefts weren't legal maneuvers for quite a while. They were introduced gradually starting at intersections where it would be a traffic benefit, for signaling the state adopted a blinking yellow arrow that then goes solid to signify the 'almost over' meaning of a typical yellow light.
But I agree with you that you should verify that no one is coming in that case; that's sound advice for most all situations, really.
This varies a lot by state. Several allow turning (after a stop) on a red arrow. Some even allow turning left on a red arrow, if it's onto a one-way street.
> Lots of drivers don't understand this.
This is logical. But, I've seen firsthand in Quebec (the city of Sherbrooke) where that's not the case. A driver may have a green arrow at the SAME TIME that a pedestrian has a walk signal. And in St. Thomas USVI I've seen opposing traffic have conflicting signals too (green arrow at same time oncoming traffic has green to go straight!)
I believe I've also seen red right turn arrows in Pennsylvania, but they don't have any special meaning there. But I couldn't say for sure.
I wonder where the driver education here is breaking down.
In PA, red arrow is just a regular red light that happens to be in a turn-only lane. All laws are the same as normal red light, the lane marking restrict your movement.
In CO, red arrow means stop and no turn on red regardless of lane markings.
Just about all traffic control laws are standardized federally except lights. That feels like the most important one to reduce confusion.
Not sure I believe this. Obviously it's a fuzzy statement but I don't think I've ever once in my life seen someone blatantly ignore oncoming traffic due to having an unprotected left signal.
I have seen that happen, though fortunately there was enough time for both drivers to avoid a crash.
This is the same in the southeast, and I assume the rest of the US.
Recently "flashing yellow" [1,2,3] has been introduced to mean left turns must yield to right of way traffic. These are gradually replacing solid green signals.
[1] https://www.txdot.gov/driver/signs-and-signals/flashing-yell...
[2] https://durhamnc.gov/1140/Flashing-Left-Turn-Arrow-Informati...
[3] https://www.penndot.gov/TravelInPA/TrafficSignalsManagement/... (PDF)
In practice that might work, but it's also a conflicting signal.
Note that whether you have a solid green or a green arrow matters. A solid green means you can turn left, but you might have cross traffic. A green arrow means you're protected and as long as other people are obeying traffic signals, you shouldn't run into other people.
Lots of drivers don't understand this.
Lots of drivers also don't understand a red right arrow (as opposed to a red solid circle) means you cannot turn right on red. Most "no right on red" intersections have both the arrow and a sign (and many drivers ignore both).