Traffic Sensors and Filter Lights (Turn Arrow Lights)

 

I've noticed lately that several intersections where there used to be a regular pattern of red light; green turn arrow; green light now seem to be skipping the turn arrow phase if there isn't a car sitting on the sensor area when the lights are changing.

In the abstract it makes sense, but practically is doesn't. Almost always, cars are approaching the intersection from a previous light seconds before the turn arrow would normally come on. But if there isn't a waiting car already, the green turn arrow phase is bypassed and the approaching cars (who were expecting to get a green arrow) have to unexpectedly stop.

The worst part is the lack of predictability. Will it do its normal green turn arrow, or won't it?

Anyone else notice this?

Where

Haven't noticed anything around where I live.

What country, province, state, city, whatever are you in?

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Nuvi 2460LMT

Normal

That's the way it's always been in areas I've lived (western states). There's no point holding up traffic already waiting at a light to burn a left turn arrow with nobody turning. As for oncoming traffic caught by a previous light, that's just luck o' the draw.

That said, there are some anomalies here in the Phoenix area. In most areas the left arrow comes on first then the green for straight ahead. In a few, the turn arrow comes on 'after' the straight ahead goes red. I.E. the normal order is reversed. The wait time is the same though.

Cheers wink

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Nuvi 760 & 660, Streetpilot, GPS III, GPS 10X

The Norm In Ontario

This the way most left turn arrows work in Ontario.

If you don't get to the intersection a certain time before the light turns green, you don't get the advanced left turn. In some cases, if there is only one or two cars there, it won't go to advance left.

It's frustrating when you're waiting to turn, because there is an advance left in the other side, but no cars turning left.

It also will cancel out the advance when there seems to be no further cars turning left. In some cases, the dummy in front of you doesn't keep pace with the cars in front of him and the advnace is halted because he was too busy texting to realize that the cars in front had all made the turn.

When there are advance left both directions, the main green comes on the same time as the advance, if there are no left turns in the opposite lane.

This makes sense. why should the other direction have to wait, if there is no one turning left in the opposite lane. It's a bit of a pain, if you got there ten seconds before the green and there was no advance, but it improves traffic flow for everyone.

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NUVI2555LMT, NUVI350

Turn arrows

davidkbrown wrote:

It also will cancel out the advance when there seems to be no further cars turning left.

When there are advance left both directions, the main green comes on the same time as the advance, if there are no left turns in the opposite lane.

That is the way all the intersections with left turn controls work in Northern Kentucky. Also the advance cancels independently each direction based on how many are in the left turn lane in the opposite direction.

Technology

at work

Turn Arrows

In the part of Florida I am in, if there is no car on the sensor, the turn arrow is not activated.
This improves the flow of traffic on the oncomingt side.

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Don't sweat the petty things and don't pet the sweaty things!

Random

It makes sense to work the way folks have described. The annoying part is that sometimes it works that way, and other times the green arrows light up even when no cars are present. Haven't been able to detect a pattern for when it will and when it won't.

I'm in a large metropolitan and suburban area. There are traffic flows that "expect" the green arrow. It's a time honored tradition. But now, unless the first approaching car races ahead to get on the sensor, tradition is broken.

Not a big deal, but worth mentioning. Thanks for the replies.

Have To Be On The Sensor

I had a case a number of years ago where the driver had likely been trained by one of driver ed places to stay a car length or more behind the stop line. They do this because if someone coming from another direction is hit, in the intersection, they have a tendency to veer to the left or the right. When you're far back, yo won't get hit.

Good logic, but in this case the sensor for the straight through light would not activate. It was on a highway and it only activated when a car was at the intersection to cross the highway.

After a reasonable time, I had to walk up and ask her to move forward. Then the light changed.

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NUVI2555LMT, NUVI350

sensor work as intended

davidkbrown wrote:

I had a case a number of years ago where the driver had likely been trained by one of driver ed places to stay a car length or more behind the stop line. They do this because if someone coming from another direction is hit, in the intersection, they have a tendency to veer to the left or the right. When you're far back, yo won't get hit.

Good logic, but in this case the sensor for the straight through light would not activate. It was on a highway and it only activated when a car was at the intersection to cross the highway.

After a reasonable time, I had to walk up and ask her to move forward. Then the light changed.

I have noticed the same problem but with very aggressive drivers that stop beyond the white line and they get frustrated when the turn light doesn’t come on unless someone comes behind them to activate the sensor.

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Garmin 38 - Magellan Gold - Garmin Yellow eTrex - Nuvi 260 - Nuvi 2460LMT - Google Nexus 7 - Toyota Entune NAV

why back-up miles of straight Traffic

Leaving the Notre Dame games letting the staight traffic though first gets rid of miles of cars first & most of them are not turning. Works alot better to move alot more cars though faster.

intersection

There is an intersection here, that late at night the sensor doesn't detect someone wanting to make a left turn. The lights cycle for the other road, but stay red for the one you're on. I usually have to flash my high beams, or run the light.

Malfunctioning light.

jfulton:

This happens alot to me on the motorcycle. IL. has a stipulation that you can treat a light as malfunctioning if this happens.

I usually let the light cycle twice, before proceeding.

Check your states laws.