Johns Creek Thru-U: City Staff Data Confirms it Will Fail

After providing a 3600-page document analyzing the data for the top ten “solutions” to the gridlock at 141 and State Bridge, City Staff is recommending a Johns Creek Thru-U.

The Plan eliminates Left turns from the busiest intersection and forces traffic to go thru the intersection, make a U-Turn and then a right turn to go toward the intended direction.

If City Council approves of these plans, construction is expected to be completed in approximately 4 years, or around 2023. 

JCP Editor, Ernest Moosa analyzed this document and data. Below are some highlights presented in their analysis. 

According to ‘ReadTime’, a website that calculates reading times for documents, it will take 138 hours to read this MASSIVE document. 

1 Printed Copy was Provided for 7 Council Members to Share.

Year 2024: 141 & State Bridge Road: 11.6% Over Capacity

City Staff & Consultants are projecting the intersection will STILL be Over Capacity with their recommendations, once construction is completed.

As you head down 141 south towards State Bridge Road, traffic is backed up. Why? The intersection at State Bridge and 141 is already over capacity by 11.6%. This is one of the causes of the backup. 

Making matters worse, the three lights at State Bridge Road, Medlock Crossing, and Old Alabama are not synchronized. In fact, they cannot be synchronized, according to Staff. Why?

Year 2024: 141 & Medlock Crossing: 18% over Capacity

Even if the lights were synchronized, that is not going to resolve the capacity issue at Medlock Crossing.

The new configuration will reroute the 2 current 141 left lanes going East on State Bridge Rd to drive thru the intersection and make a U-Turn at Medlock Crossing (Honey Baked Hams) and then right onto State Bridge Rd (East). 

Medlock Crossing will be a whopping 18% over Capacity, 2 years after construction is completed. 

This will be your new bottleneck. 

 

141 State Bridge Thru-U
2015 Rendering of the Thru-U Design

These plans were previously and vehemently opposed by the community, yet City Staff, consultants, and certain Councilmen have resurrected the plans, and buried them in a 3600 page document. 

Year 2024: 141 & Old Alabama Road: 10% over Capacity

The light at 141 and Old Alabama will create a similar bottleneck issue for traffic heading north on 141. And the same effect happens when the left turning traffic from Old Alabama makes a left and turns north.

So after spending millions and millions of dollars, drivers will see a green light at 141 and State Bridge 53% of the time, less than today, and still be traveling through intersections that are well over capacity.

For all of the comments by the Mayor and staff about 10 pounds of sugar in a five-pound bag, one can only wonder why we are just moving the sugar from one inappropriate bag to another.

All of this traffic will need to be serviced by a light signal that is green only 50% of the time. 

141 at State Bridge is green 84 of 160 seconds or 53% of the time(less than today). But 141 at Medlock Crossing is green 80 of 160 seconds, or 50% of the time. This creates a bottleneck as vehicles back up in the southbound lanes between State Bridge and Medlock Crossing.

With both lights having different green times and the same total cycle times they will be in sync only occasionally.

What makes it worse is that when 141 Southbound is stopped, the U-turn Traffic from State Bridge Westbound will be making the right to head south on 141, but the light ahead has a 50/50 chance of being red. There will be nowhere to go.

What Really Needs to Happen? The Weakest Link

The Weakest Link of this corridor needs to be designed to handle as much volume in traffic as needed. And there are multiple ways to do so. But those options seem to be off the table.

The primary design objective should be to get the lights green on 141 more than 65% of the time. To accomplish this, you will need to do a few things:

  1. Three lanes through southbound on 141: We have asked for that for years. It’s built into their current proposals, yet they have refused to do this. There is not a logical reason as to why they have not done this already. This increases the southbound volume by 42% if the right lane is a shared turn lane. If we add a new right turn lane only, this capacity increase is 50%.
  2. Three left turn lanes from 141 Southbound to State Bridge Road East: Today that turn light last 20 seconds. Three lanes increases the capacity by 50%.
  3. Medlock Crossing needs to be reconfigured for two left turn lanes and two through lanes on each side: this reduces the time needed to service those traffic movements and allows the light on 141 to be green for longer periods of time.
  4. Three left turn lanes from State Bridge West Bound to 141 South: Twenty-six percent of State Bridge West Traffic turns left here. This will increase capacity by 50 %
  5. Three lanes through NorthBound on 141 and a continuous flow right lane from 141 North to State Bridge East. The through lane can merge left by the last entrance to Publix Shopping Center
  6. Three lanes through west bound on State Bridge: This third lane should extend to the last entrance to Johns Creek High School.
  7. Three lanes through southbound at Old Alabama Road and a continuous right turn lane at Old Alabama Road: The right lane through can merge left before the small church on the right.
  8. Three left turn lanes from Old Alabama Road to 141 North: This should have been the original design.
  9. Remove the traffic light in front of Publix/Target and allow both entrances to be right in/right out only.

Bottom line: All of our intersections need to be built for much more capacity than they will need. Traffic engineers historically have only added capacity after years of an intersection being over capacity. Slowly that is changing. If you look at the proposed intersection at Parsons Road and Abbotts Bridge you will see not one but two right turn lanes from Parsons to Abbotts Bridge. That is more capacity than needed. And it will allow the light on Abbotts Bridge to be green longer, allowing more traffic to move along the corridor.

We need to apply that same approach at all of our intersections on our major roads.

Source: City of Johns Creek. Report created by Wolverton. 

Here is the complete document…

Here is a PDF of the extracted pages from the document referred to above. 

 

5 thoughts on “Johns Creek Thru-U: City Staff Data Confirms it Will Fail”

  1. If city staff proclaims the lights at and near State, Medlock, and Old Alabama roads can’t be synchronized, then I’d like to see the written reasons and/or study that supports this counterfeit thesis. I firmly doubt city staff, our elected officials, consultants, etc. can produce anything of substance to support this. That’s because the City’s consultants, engineers, and contractors will make substantially more money on a large scale multi-year road and intersection improvement project vs. synchronizing the lights.

    These private companies make more money by creating large scale self-serving projects off of the backs of JC’s taxpayers vs. advocating for more cost-effective traffic solutions. And, some of the money they make is converted into political contributions and a jobs program for family and friends.

    Synchronizing the lights will be more timely, cost-effective, and less disruptive to the citizens and visitors of JC.

    1. The City is not proclaiming this about the lights directly. But the light timing is detailed in the PDF report. To be able to be synchronized, the three lights mentioned would each need to have the same amount of green time for north and south travel. They do not. Medlock Crossing will have the least amount of green time for north and south traffic of the three lights. They could of course decide to change that, but then this will reduce the number of vehicles that can make U-turns.

  2. The fix is simple. Eliminate the lights and divert the traffic. Flyover lanes! Worried about an ugly intersection? Too late we are already there and have been. All of the proposed changes will only make things worse and will not keep pace with the growth up north.

  3. Increasing the time and linking the lights will only dump more traffic and further gridlock Peachtree corners. Keep your mess in your own backyard please.

  4. Sounds horrible! No left turns, going into a shopping Center and making a u turn. Are you people drinking or smoking something?

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