McGinnis ‘Florida-T’ provides traffic boost

Road improvement makes intersection more efficient

Hans Haase/


JOHNS CREEK, Ga. – A minimal traffic improvement to the McGinnis Ferry-Sargent Road intersection is yielding good results, according to city transportation officials.

Called a Florida-T intersection, it is an interim fix until the widening of McGinnis Ferry Road has been completed. But that small fix has reduced traffic queues and delays.

“That intersection had been No. 1 last year as far as complaints,” said Johns Creek Public Works Director Tom Black.

He said people eastbound on McGinnis Ferry Road would queue up, and motorists wanting to turn left off Sargent Road would be held up by red lights even when there was no traffic on McGinnis.

The solution, funded in last year’s budget, was something called a Florida-T, Black said. The solution was simply to move the merging of three east-bound McGinnis lanes. Instead of the left lane peeling off to turn and the middle and right lanes merging beyond the Sargent traffic signal, all of that happens before reaching the signal at Sargent Road.

“We just moved that merge back before McGinnis traffic got to the light. Now there is just a dedicated left turn at the intersection (eastbound) and east-bound’s through traffic,” Black said. “People making a left turn onto McGinnis from Sargent get a flashing yellow light and move anytime when it is clear.”

The city’s computerized traffic monitoring system senses when Sargent left-turns are blocked and gives it a green turn signal while turning the light red to McGinnis traffic.

What is important to motorists is that the change has cut McGinnis wait-times from an average of 51.4 seconds to 22.4 seconds, more than half.

“This let people who were sitting at the intersection for no reason to move through it,” Black said.

The intersection is working “beautifully,” he said.

Meanwhile, Sargent Road traffic turning right does not stop. It has a long merge lane all the way to Hospital Parkway.

Eastbound traffic does not have to merge at the signal with other eastbound traffic. That merge already has occurred west of the signal and the intersection.

So you have a “continuous green” flow of traffic eastbound until the red light stops it.

Deputy Director of Public Works – Traffic Tom Udell said the intersection was modeled to compare the wait times for morning and afternoon rush hour traffic. It cut those wait times by more than half.

“The traffic queues have been reduced considerably,” Udell said. “But removing conflict points has also improved the safety. This allows for merging traffic to occur after or before the intersection, and that reduces accidents as well.”

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