PTC needs — not more red lights — but a change in tactics
Before contracting for yet another traffic light at Line Creek in Peachtree City or anywhere else, consideration should first be given to updating traffic light programming as has been done in Fayetteville.
Most every traffic light in Peachtree City represents an impediment to through traffic because of outdated programming. Improving the flow of through traffic is key in mitigating the daily gridlock situation we have on Ga. Highway 54 West. And adding another traffic light with outdated programming will only exacerbate the problem.
Running the gauntlet of lights on Hwy. 54 east and west is evidence of what this programming does to impede traffic flow, which is why I grimace when there’s talk about the need for more traffic lights.
In Peachtree City, most signals are programmed to run four cycles: Two cycles for through traffic and two cycles for left turn traffic. Let’s use the signal at the intersection of Hwy. 54 and Peachtree Parkway as one of many examples of this programming:
Here, left turn traffic has priority over through traffic and gets a green arrow while through traffic must sit at a red, which should never be the case at a non-major intersection with single left-turn lanes.
Through traffic must wait for this cycle to end before getting a green, and they’re generally held beyond the time it takes for all left turn traffic to clear. Traffic congestion is obviously proportionate to the length of time that through traffic is held at a light, and this programming makes the worst of it.
Next we enter the second cycle, where left turn traffic is stopped with a red arrow and through traffic is finally given a green. Unfortunately, this red arrow prevents any remaining left turners from yielding and turning left after oncoming traffic clears.
They must now sit through 1) the through traffic cycle, 2) the cross traffic left-turn cycle, 3) the cross-through traffic cycle and finally 4) they get a green arrow and may proceed. This entire process is a waste of time and represents unnecessary inefficiency in traffic control.
The flip-side about red arrows is that we have to sit and wait at them, even in the middle of the night, often with no oncoming traffic. The arrow then turns green just in time to stop a herd of oncoming cars (through traffic) when we would’ve been long gone had we been allowed to yield and go.
We may have been the only car to turn left but oncoming through traffic will have to sit at a red light until the arrow cycles out. This is yet another illustration of what an impediment red arrows are to traffic flow.
Fayetteville, on the other hand, has brilliantly updated their signal programming such that red arrows are almost completely eliminated. This mostly erases the two left turn cycles that impede the all-important through traffic.
In other words, both cycles give priority to through traffic instead of left turn traffic, which helps prevent traffic backups. Except for at major intersections, a flashing yellow arrow has replaced the red arrow which allows left turn traffic to yield and go while through traffic flows unimpeded.
Should anyone remain on the left turn switch at the end of the cycle, then and only then is a green arrow given that stops opposing traffic. Conversely, if no one’s on the switch at the end of the cycle, then the need for a green arrow is eliminated and cross traffic is then allowed to flow in the same manner.
The key here is facilitating the flow of main and cross-flow through traffic which allows for a significant improvement in traffic flow efficiency over what Peachtree City currently uses.
Controlled red arrows should only exist at major intersections with two left-turn lanes (such as Hwys. 54/74) or where oncoming traffic is not fully visible because of hills or sharp curves. And the flashing yellow arrow makes clear the difference in signaling so that there’s no confusion between the two.
It’s essential that Peachtree City follow Fayetteville’s lead and update their signals, especially before considering more of them. Over time this will save fuel, pollution, congestion, frustration and wasted time sitting at traffic lights.
Ralph P. Trapaga (formerly of Peachtree City)