Left Turn Yield on Green sign
You may turn left on a plain green light, but only after yielding to oncoming traffic and pedestrians. There is no protected arrow guaranteeing your turn.
Federal designation R10-12 in the MUTCD, the national standard every state signs to. Mounted just below the signal head at intersections that use a flashing yellow arrow for the left turn phase instead of a dedicated green arrow.
How to recognise it
This sign is a wide rectangle in white, the standard background for a rule you must obey. These carry the force of law. Ignore one and you have broken a traffic rule, not just a guideline. Most are white rectangles with black text, and the handful that are not, the stop and yield signs, get their own unmistakable shapes.
What the test wants you to know
This sign usually sits under a flashing yellow arrow signal, and its whole purpose is to head off the mistaken belief that a green ball gives left turners the same right of way as a green arrow. Examiners use it to check whether you know a circular green never protects a turn.
Practise it
Reading about a sign is not the same as recognising it in half a second with an examiner watching. Every state road signs test on this site shows the sign and asks you to name it, then shows four faces and asks you to pick the right one.
Stop
Yield
Do Not Enter
Wrong Way
Speed Limit
One Way