Explanation
🚦Protected-Permissive Left-Turn Signal - (FYA) signals
🔴 Red Light: Prohibits movement and left turns (same as a standard traffic light). Similarly, a solid green light allows normal movement. Similarly, solid yellow light warns that the signal is changing from green to red, and you should stop if it is safe to do so.
⬅ 🟢 Steady Green Arrow: Means a protected turn—oncoming traffic has a red light, so you can turn left with the right-of-way.
⬅ 🟡 Steady Yellow Arrow: Warns that the protected phase is ending and a red signal is about to appear (prepare to stop or clear the intersection if you are already turning).
⬅ ⚡ Flashing Yellow Arrow: Allows you to turn left, but you must yield to oncoming traffic and pedestrians.
Before the introduction of flashing yellow arrow (FYA) signals, a standard circular green signal was often used for permitted left turns.
Many drivers, out of habit, perceived the green color as an absolute signal to move ("green means go") and turned left while forgetting the need to yield to oncoming traffic, which often led to accidents.
This is exactly why the Federal Highway Administration (FHWA) introduced the flashing yellow arrow as a national standard: a flashing yellow light is intuitively associated with caution and the need to be careful (unlike green), making it clear to drivers that they must yield to oncoming vehicles and pedestrians.