Thank you for your comment. The issue with the left turn at this intersection is that there is no left turn lane and no detector that can tell when a driver is wanting to turn left onto Vermack. This means that if the left turn arrow phase is active, it has to come on during every cycle whether there is a need for it or not, which adds delay to all of the other directions. Because there isn't a turn lane, it also means that the turn arrow doesn't help unless one of the first few cars in the queue is turning left.

At one point we tested this during the PM rush hour, and the time taken away from northbound and eastbound traffic meant that the backups were much longer and lasted later into the evening. We also saw that when drivers knew they could wait for an arrow, they were more likely to sit and wait rather than looking for a gap to turn. This ended up creating longer delays for westbound traffic as well.

Based on our analysis and testing, having the arrow active in the morning peak hour is the most effective time of day to use it because of the heavy westbound traffic, and there still is enough time to serve all of the remaining traffic. During the other times of the day it has more downside than upside. Please know that the city is still working on long-term solutions to better serve all the drivers on the corridor.

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Observing ONE day is not full analysis. With school starting and after school activities in which turning left from Mt. Vernon unto Vermack is a common driving activity, maybe it should be relooked at. Maybe have the left turn arrow all the time at the end of the cycle then...Are you waiting for accidents? This one was nearly avoided as both cars slammed on breaks. This was at 4:30 pm on a Monday. Car waiting to turn left did have their blinker on and we were also waiting to turn left. We had to wait another light cycle. Took 3 light cycles to turn left!!!

I think it would be helpful to have the left turn arrow in the late afternoon/early evening. Please re-consider adding another cycle for the late afternoon rush hour traffic. The traffic going north on Mt. Vernon at the end of the day makes it a real challenge to turn left onto Vermack. Even if only 5-6 cars can get through, it would be better than the 1 or 2 going through now. Thank you!

Therefore, the city of Dunwoody thinks it is alright for those traveling eastbound have higher priority than those traveling westbound!! When one or two cars can only get through an intersection and backing up those behind them is acceptable, that is unbelievable. Why as taxpayers did we pay to have a new light with a Left Turn signal even installed? Long-term solution when something simple can be done now?

The project to improve this intersection is scheduled to begin in early 2018. Left turn lanes with left turn arrows will be added in both directions on Mount Vernon and on Vermack.

GREAT NEWS! But in the meantime, it would be WONDERFUL to help us westbound drivers turn left on Vermack and/or not be stuck behind those who do want to turn left and use that arrow for the afternoons (2 pm till 9 pm) or all day.

The priority level of this left turn project has to be raised to top priority AS IT IS MANY MANY YEARS OVERDUE.
WE are relative newcomers to Dunwoody Club Forest subdivision (since 1997) and this has been a problem from our first day here. The left turn issue from Mt Vernon onto Vermack should have been done at the same time as they did the Mt. Vernon re-construction and stopped it one block BEFORE VERMACK

It can't take as long and have as many problems as the Tilly MIll intersection.....

In the interim, let's make the greatest use the equipment that has been installed to ease left turns onto Vermack; which is where the greatest .majority of left turns are made.
The residents who live in this area have been living with it as well as observing it.

Turning on the left turn arrow at all times could be seen as a "Beta/experiment/field test..." for perhaps a month now that school and after school programs are in session. Analysis from one evening's observation is not conclusive enough to make a decision. The city put in that light for a reason, OUR TAX DOLLARS paid for it (like it is your million dollar new home on Ashford Dunwoody). Why should we wait till "early 2018" (March/April???) to start construction. Let us be safer turning left or knowing traffic can turn left at the next green cycle so cars to not try to go around, making it unsafe to all.

As to those going Eastbound and maybe having to wait an extra minute or 2 if no cars happen to be turning left then, well...take a drive down Mt. Vernon towards Ashford Dunwoody and then down Ashford Dunwoody towards 285 on a Sunday Morning and the waits for zero traffic are at every light. It's just the way Dunwoody does things...why not here too? Let's be consistent.

I used the left turn arrow about an hour ago. Thank you for having it work after morning rush hour! It made a good difference. I look foward to turning left there later today!

I was very disappointed at 5:30 pm. I was a second car at the red light, and I had to wait until the light turned yellow before I could turn left

As cars are not to be in the middle of the intersection, I stayed back. However, cars and trucks behind me when around me coming very close to clipping my back corner and going up over the curb in order to go around me on the right in order to go straight.

VERY, VERY disappointing. If I were all the way back then only two cars, the one before me who went straight and myself, would have made that light. Those turning left onto Vermack and those wanting to go westbound on Mount Vernon should get the same priority in the evenings to get kids and to do other things in the Dunwoody area that might be towards the high school and Chamblee Dunwoody as those going eastbound.

I failed to say in my last post that the arrow was not showing up at 5:30 p.m. like it was around noon. Dunwoody had said in an earlier post it was either on or off and they could not change the timing, obviously that was not true. Please have the arrow working during the afternoon & evening hours.

I failed to say in my last post that the arrow was not showing up at 5:30 p.m. like it was around noon. Dunwoody had said in an earlier post it was either on or off and they could not change the timing, obviously that was not true. Please have the arrow working during the afternoon & evening hours.

We have been looking at using the westbound left turn arrow during more parts of the day, and based on the analysis we are going to continue using it except during the afternoon rush hour. I know this is not everything you were hoping for so I would like explain further.

I am frequently asked, "why can't you just give more time to each direction?" The problem is that there are only 3,600 seconds in an hour to be divided up. Because there is no westbound turn lane, the traffic signal controller doesn't know if the first few cars in the line are turning left or going straight, which means that if the arrow comes on it has to be up for a fixed amount of time in every phase. Every second programmed for the westbound left turn is a second that has to be taken away from either the eastbound or northbound traffic phases (even if no cars are turning left).

I'm attaching a screenshot from Google Maps of the PM rush hour earlier this week. It shows how far the delays can extend in each direction. You are right that the westbound queue can extend several hundred feet from waiting for one person to turn left. But the eastbound traffic queue can extend all the way to Dunwoody Village Parkway, and the northbound traffic queue can extend to Dunwoody High School, because their volumes are so much higher.

If I were to take 5-10 seconds of every cycle away from those directions during rush hour, the eastbound queue would extend back into the Chamblee Dunwoody/Mt Vernon intersection and the northbound queue would extend into the Vermack/Womack intersection. That could create gridlock on multiple corridors and negatively impact thousands of people.

Again, we have been working to improve traffic flow at this intersection for all users, and if you are turning left at this intersection it should be easier for you for most of the hours of the day. Further improvement will come when the intersection improvements are complete in the next year, as we are doing our best to serve all of the citizens of Dunwoody.

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