I agree with both of your comments 😬

This intersection has been really bad lately. It would be great if cops could come and enforce the rules for a bit and ticket the offenders. Even worse than the traffic is the multiple road rage incidents I’ve witnessed here too - one of which I called 911 on.

Our police officers have been engaging in enforcement action to address intersection blocking at this location. Unfortunately, we cannot maintain an officer at any location throughout peak commute periods due to other needs / emergency response, and there are many motorists who will obey the law only when a police officer is visible.

Further adjusting signal timing has had negligible impact, as the primary issue at the GA400 / Windward Parkway Interchange is one of capacity. There are simply more vehicles converging on the corridor during peak commuting periods than the road has capacity to handle. Think of it like trying to put water into a glass. Once the glass is full, running the water for a longer period of time just means water is being wasted because there is no more room in the glass. At the same time, because of safety issues, we have to allow vehicles exiting GA400 to access Windward Parkway at a rate sufficient to minimize backups on GA400.

So, in this case, we need more capacity on westbound Windward Parkway, which is what is being created with the construction project that is currently underway. That project is creating an additional left turn lane from the exit ramp that becomes a dedicated right turn lane onto Deerfield Parkway. There has been significant growth in vehicles making that movement, and this project will address the need that has been created by motorists traveling to Milton and points north.

I agree that this is partially an issue of capacity, but it seems to me that the timing of this intersection is off.

The problem is that the 400 SB off-ramp left turn (towards Windward EB) and the 400 NB off-ramp left turn (towards Windward WB) each get a green light at the same time. This leads both directions into a red light under the 400 underpass and causes the backup.

Also, the drivers blocking the box are doing it through no fault of their own, as you have almost no visibility of the underpass stoplights when turning left and the intersection fills up very quickly with the volume of cars at this intersection.

Anyway, this exact same issue happened in August of last year, and was fixed with a timing adjustment (thanks to Arash Roshandeh I believe!). It appears that the timing has been tinkered with again, somewhere around the week of May 20. I think the timing needs to be switched back to however it was timed a couple weeks ago, as this was much more effective in moving cars off 400 without excessive backup.

JohnA, thanks for this detailed description. Hopefully someone will look into it further now instead of just a "live with it" response. I know we all have a lot of work to do and I can certainly appreciate the job of law enforcement. We aren't asking for much and it seems like a simple tweek; at least from our perspective. However, if laws aren't enforced, doesn't it just encourage the bad behavior all the more?

Thank you for reporting this. We'll re-check signal timing at the intersections of GA-400 northbound and southbound ramps with Windward Parkway, and adjust them accordingly. Timing plans of those signals have not been changed from months ago. If you have any questions, please contact us at 678-297-6260.

Issue 5972790 has been marked as a duplicate of this issue.

Issue 5972672 has been marked as a duplicate of this issue.

The City continues to monitor this location and has made adjustments to the signal timing in an effort to better address traffic. Unfortunately, the main cause of the issue is one of capacity; there simply being more cars traveling through the interchange than the roadway can handle. We currently have under construction a project that will add capacity to westbound Windward Parkway, relieve congestion, and improve traffic flow. It must be stated, however, that no improvements to the roadway or changes to signal timing will be effective unless drivers alter their behavior and stop blocking intersections.

The issue is not capacity. The issue is the light on the opposite side of the highway is red, while coming off the highway is green. Nobody moves, so the light just cycles, while people are in the intersection. It congests traffic and backs it up on the highway all the way back to the previous exits.

Issue 6007220 has been marked as a duplicate of this issue.

AGAIN - the issue is not an issue of capacity. When exiting 400n onto Windward Pky., the light stays red for 2 minutes and 45 seconds. The light stays green for 45 seconds. It is very simple to see what the problem is. You have to be a quarter of the way from the intersection to get through the green light. Meanwhile, minimal cars are travelling east and west on Windward while the exit is so congested it is backing up cars on 400 to the previous exit.

We'll keep monitoring traffic movements and adjust signal timings accordingly.

The City of Alpharetta has resolved this request.