Blinking turn arrows?

[Troubleshooter]

Originally Posted by Oildog

Doesn't a green light serve the same function? You can turn if its safe?

Not quite.

The difference is the meaning given to traffic that is NOT turning left.

The circular green releases other traffic besides the permissive turn.

The flashing yellow arrow does not release other traffic.

This means the flashing yellow arrow can prevent "yellow trap" by allowing a permissive left turn while the circular signals are red.

This allows more efficient signal sequences, including the lead-lag sequence which helps green light progression on two-way streets.

[Troubleshooter]

Originally Posted by jambo101

Around here (Montreal) if you have a blinking left turn arrow it means you have the right of way to make that left turn and oncoming traffic has a red light until the arrow stops flashing.

That is Canada law and a green arrow.

It does not apply in the US, where flashing green is outlawed.

[Troubleshooter]

Originally Posted by DRob4JC

I think what happens is that in the past, an normal intersection would have a stoplight for each lane and a left turn light (with the arrow) for the turning lane. So what would happen in empty areas at night traffic would have to stop until the green turn light came on.

The blinking yellow light is a programming fix so they would not have to change any hard equipment to achieve the same function of a yield left turn on green.

Wrong. There must be two yellow arrows in the flashing yellow arrow face, one for the permissive turn and one fir the clearance. This way, the light moves to a different signal section when the clearance starts.

The purpose is to eliminate a sneaky hazard called "yellow trap."

[Troubleshooter]

Originally Posted by ryanez5

San Antonio was the test city for this design. Something in the Express-News last year explained that people had a hard time understanding what a solid red + a green arrow meant, so TxDOT came up with this. Pretty simple if you know that a blinking yellow means yield. Thats really the only difference; red arrow is still stop, solid yellow means the light is about to turn red, blinking yellow is still yield and solid green is still go go go

It was actually invented in Illinois in the 1960s, but dropped because it caused accidents (they didn't have a clearance before changing from green arrow to flashing yellow arrow). i drove through that intersection.

The first use of the modern version was in Reno Nevada.

it is now part of the National Manual if Uniform traffic Control Devices.

The purpose is not understanding signals, but elimination of the yellow trap hazard. To do this, a signal indication was needed that releases permissive left turns without releasing straight ahead traffic. The circular green can not do this.

[CaliforniaIsPrettyGreat]

Originally Posted by Oildog

Doesn't a green light serve the same function? You can turn if its safe?

No Oildog. No.

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