Jon, I reported this months ago. City said something about that traffic light being controlled by some GDOT contractor who refused to do anything about it. It's absolutely ridiculous. I don't even go that way anymore.

It seems ridiculous that the city can spend tens of thousands of dollars to build an electronic billboard carrying lawyer's ads right at this same intersection, but can't spend one man-hour of time to adjust the duration of the left turn signal arrow and alleviate a traffic back-up on Mount Vernon.

I agree Jon...it's absolutely ludicrous...

City of Sandy Springs addressed this issue on 07/15/2016, service request #16-037880.

I agree with Jon. This problem continues. Sometimes 5-6 cars can make it. Most other times only 3. During these times, the turn lane can have as many as 10-15 cars in it. Which means the left straight lane is blocked. Come on Sandy Springs you can do better than that.....

This issue has been received by the City of Sandy Springs. Your service request ID is #16-038554.

I went through the intersection again today, deliberately to measure the time. While I admit that going "One one thousand, two one thousand" isn't very scientific, I was getting about 6 seconds between the green arrow and the yellow arrow. This may be enough during low traffic times, but not enough during rush hour. Friday, I wanted for three light changes to use the arrow.
Plus, Sandy Springs people, why don't you tell us WHAT you are doing when you say you have fix the problem. Did you add one second? two seconds? Let us know. Don't keep us in the dark.,

City of Sandy Springs addressed this issue on 07/18/2016, service request #16-038554.