‘Gapping out’ an annoyance at stop lights

The in basket: Tom Baker writes, “Sometimes you will hear a left turn had a short signal. If the drivers are distracted and not paying attention and the signal changes to green, if there is a break (gap) between the cars, the signal may think there are no more cars in the left turn, and change to red.

The gap can vary significantly between signals and time of day. I know that 11th and Naval will change quickly if there is a gap between the cars turning left. Westbound Loxie Eagans and National does not change even with large gaps, it may have a fixed time for the left turn.

“Usually the driver with the gap ahead gets through but not the ones behind,” he said.

The out basket: This is a frustrating fact of driving life, when someone ahead of you seems unaware of or indifferent to the concept of traffic signals “gapping out.”

Signals usually have a preset minimum and maximum length of green. If no vehicle crosses its detectors for a designated length of time, usually three or four seconds, after the minimum time has elapsed, it will conclude no cars are waiting and change to yellow before the maximum.

I see it most often at signals with a right turn lane. When one or more cars move right early, it can leave no one crossing the sensors in the through lane for that designated gap time.

Or, as Tom says, a driver may not see the light has changed, or just be a dawdler, and leave four seconds or so between him and the car ahead. That driver usually gets through on the yellow, but not those behind him.

There’s not much to be done abut the right turn lane situation, other than delaying one’s move to the right, which can create a lane change collision possibility. But I hope this column alerts a few uninformed drivers to what it means to those behind them when they don’t keep a short distance between them and the car ahead at green lights.

It occurred to me as I wrote this that I didn’t know if the new optical sensors mounted on the signal cross-arms that are replacing the in-pavement wires (called “loops”) that were the industry standard for decades, have gap times.

Yes, they do, says Jeff Shea, Kitsap County’s traffic engineer. “The optical detectors work the exact same way as loops, only they use optical technology.  The maximum and minimum greens and gaps are set up the same way they are for loops.  So if no traffic is on an approach after a certain length of time, the light can gap out and change phases.”

2 thoughts on “‘Gapping out’ an annoyance at stop lights

  1. It seems Kitsap County has installed new stop lights at the wrong intersection of Levin & Ridgetop. The traffic backup is at Blaine & Ridgetop. At 6pm today there were 9 cars waiting on Blaine to turn right onto Ridgetop. Is their a logical explanation?

  2. It may be rude, but when I am behind someone who is holding up traffic because they are usually on their phone and the light turns green and they dont go, I will lay on my horn. And I dont care if they flip me the bird or yell and cuss at me, because I just put that driver on notice to other drivers that you are not paying attention. I have at times when it is clear, I have gone around a driver and followed by other cars. drivers out there just cant seem to get off their phones. I work traffic control and for every 100 cars that pass me more than half of them are on their phones. Get off the phones and drive.

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