Sugar Land Experiments with Flashing Yellow Arrows (Dallas, Boyd: lawyer, college)

[Troubleshooter]

Originally Posted by HookTheBrotherUp

Just another example of our government thinking we are too stupid to judge our own safety. But, then you have drivers who are actually clueless, and drivers from foreign countries where traffic laws don't mean anything, and then carry that attitude with them to the US.

This is not about driver stupidity. It is about the driver not having enough information to make the correct decision. And it is about a few court decisions requiring government to act:

Several trial courts and one appellate court have ruled that in a collision involving a signal producing yellow trap, that government was at fault for installing such a signal sequence. I quote one of the rulings: "This signal sequence causes a virtual trap for drivers. I find that neither driver is liable for the accident, and that both are entitled to sue the state."

The rule of legal precedent thus makes governments liable if they allow their signals to cause yellow trap. It is also now against federal standards for a signal to produce a yellow trap sequence without a warning sign.

Preventing yellow trap by changing the sequence of lights removes several tools for smooth traffic flow from the engineer's toolbox. The flashing yellow arrow removes the yellow-trap hazard, making those tools available again.

The advantages of the flashing yellow arrow:

- Prevents yellow trap.

- Allows the use of lead-lag phasing with permissive turns, making possible the progression of green lights from intersection to intersection on more two-way streets.

- Removes the need for exclusively protected turns (red arrow when not showing protected green arrow or yellow clearance) at many intersections.

- Allows changing the left turn phasing according to time of day or traffic volumes. The signal can change between exclusively protected, protected/permitted, and exclusively permitted as the traffic needs. It can also change the sequence between lead-lead, lead-lag, and lag-lag as needed.

None of these tools can be used if the left turn is made on the circular green instead of the flashing yellow arrow.

Many years ago in the 80s and new to Houston, I recall being in a left turning lane waiting for a green arrow, but then this Asian woman who was in the far right lane looked around, and proceeded to make left turn across three lanes, including mine. I guess she was ahead of the game and knew this flashing yellow arrow would eventally be installed in Sugarland.

This is actually the way one Asian country does left turns. The left turning drivers wait in the left turn lane at the right side of the road. When the signal turns yellow, they drive across the intersection to the far right corner and then turn, stopping for the signal for the other street. Then when the signal turns green for the other street, they complete their turns.

New York once had this in the 1920s, but quickly abandoned it.

Seriously though, I frequent Europe often, and drive there. I kind of like their green lights that flash to alert drivers that the lights are about to change. In some cities, it is the yellow light that flashes.

We used to have that in Pennsylvania. The yellow light came on two seconds before the green went off. Then the regular yellow period began. But the federal government banned this, because too many drivers sped up to make the light from too far away.

[astrohip]

Originally Posted by Troubleshooter

Several trial courts and one appellate court have ruled that in a collision involving a signal producing yellow trap, that government was at fault for installing such a signal sequence. I quote one of the rulings: "This signal sequence causes a virtual trap for drivers. I find that neither driver is liable for the accident, and that both are entitled to sue the state."

1) What is a "yellow trap"? I am not familiar with that term.

2) Could you provide a link to the ruling you quote? I am stunned a court ruled that multiple parties can sue a state, and would like to learn more.

Thanks!

[Sampaguita]

Originally Posted by HookTheBrotherUp

Just another example of our government thinking we are too stupid to judge our own safety. But, then you have drivers who are actually clueless, and drivers from foreign countries where traffic laws don't mean anything, and then carry that attitude with them to the US.

Many years ago in the 80s and new to Houston, I recall being in a left turning lane waiting for a green arrow, but then this Asian woman who was in the far right lane looked around, and proceeded to make left turn across three lanes, including mine. I guess she was ahead of the game and knew this flashing yellow arrow would eventally be installed in Sugarland.

Seriously though, I frequent Europe often, and drive there. I kind of like their green lights that flash to alert drivers that the lights are about to change. In some cities, it is the yellow light that flashes.

There are plenty of US-born/raised drivers out there without a clue or who could care less about driving rules. As well, there are plenty of non-Asian women pulling the left-turn-across-the-3-lanes move.

It would be nice if people would just follow the rules already in place and concentrate on their driving instead of yakking incessantly or texting on their cell phones.

[Chh2]

I think they just need to do away with all signals and just install a single sign that reads, 'Good Luck!' to everyone crossing the intersection.

[astrohip]

Originally Posted by astrohip

1) What is a "yellow trap"? I am not familiar with that term.

D'oh! Answered my own question, just needed to read a little closer.

If I understand correctly, then the light at Richmond & Montrose creates a yellow trap. The left turn signal for the drivers on Richmond has both a green arrow and a green ball (and a yellow & red). Hanging under the signal is a sign that says (and I'm paraphrasing poorly) "Protected left on green arrow only".

As I drive up, if I have a green arrow, I can fly thru the turn. Sometimes I drive up, and the main lanes have red lights and the turn has the green ball. I interpret this to mean the other direction has the green and the right-of-way (hence the non-turning traffic must stop), but I can turn if it's clear.

Am I interpreting this correctly, and is this yellow trap?

[Troubleshooter]

Originally Posted by astrohip

1) What is a "yellow trap"? I am not familiar with that term.

2) Could you provide a link to the ruling you quote? I am stunned a court ruled that multiple parties can sue a state, and would like to learn more.

Thanks!

I can't provide the link, because I would have no way of knowing where to find it on the Internet. This particular ruling was in a magazine from the 1970s. I cited it from memory. I have the magazine, but I can't tell you WHICH magazine it is without a lengthy search. The judge said the state used very bad judgment in installing a signal with yellow trap (but it was not called yellow trap then).

Yellow trap occurs when:

1. Both directions on the same street have circular greens.

2. Left turns are permitted on circular green.

3. The signals for one direction on the street turn yellow, but the signals for the other direction remain green.

4. A driver waiting to turn left sees the yellow light, and wrongly assumes the signals for the other direction are also turning yellow.

5. This driver turns across live traffic that still has a green light.

6. Neither driver realizes that anything is wrong, until they realize they are on a collision course.

7. An accident occurs if the other driver is not paying attention.

[jimmyev]

Originally Posted by Troubleshooter

I can't provide the link, because I would have no way of knowing where to find it on the Internet. This particular ruling was in a magazine from the 1970s. I cited it from memory. I have the magazine, but I can't tell you WHICH magazine it is without a lengthy search. The judge said the state used very bad judgment in installing a signal with yellow trap (but it was not called yellow trap then).

Yellow trap occurs when:

1. Both directions on the same street have circular greens.

2. Left turns are permitted on circular green.

3. The signals for one direction on the street turn yellow, but the signals for the other direction remain green.

4. A driver waiting to turn left sees the yellow light, and wrongly assumes the signals for the other direction are also turning yellow.

5. This driver turns across live traffic that still has a green light.

6. Neither driver realizes that anything is wrong, until they realize they are on a collision course.

7. An accident occurs if the other driver is not paying attention.

I think most places deal with this by hanging a sign, "Opposing traffic has prolonged green" or something to that effect.

[Troubleshooter]

The Manual of Uniform Traffic Control Devices has required that yellow trap be eliminated or signed since 2008. But signing it is not always appropriate. The sign says "ONCOMING TRAFFIC HAS EXTENDED GREEN" if the yellow trap is frequent, or "ONCOMING TRAFFIC MAY HAVE EXTENDED GREEN" if the yellow trap occurs only when empty traffic movements are skipped by the signal.

But the better solution is to use a permissive turn indication that is not tied to the thru movement. By using the flashing yellow arrow, the engineer can make the signal stop the permissive turns at a safe time, instead of having to stop it at the wrong time (when the thru movement ends) because a circular green was used.

[Troubleshooter]

Originally Posted by astrohip

D'oh! Answered my own question, just needed to read a little closer.

If I understand correctly, then the light at Richmond & Montrose creates a yellow trap. The left turn signal for the drivers on Richmond has both a green arrow and a green ball (and a yellow & red). Hanging under the signal is a sign that says (and I'm paraphrasing poorly) "Protected left on green arrow only".

As I drive up, if I have a green arrow, I can fly thru the turn. Sometimes I drive up, and the main lanes have red lights and the turn has the green ball. I interpret this to mean the other direction has the green and the right-of-way (hence the non-turning traffic must stop), but I can turn if it's clear.

Am I interpreting this correctly, and is this yellow trap?

If the left turn has a green ball while the thru lanes are red, is the green louvered or shielded so the thru lanes can't see the green ball?

If so, that is Dallas Phasing, an early method of preventing yellow trap. Up until this year, Dallas Phasing was allowed for the prevention of yellow trap. But the new MUTCD (Manual of Uniform Traffic Control Devices) has prohibited Dallas Phasing in favor of the flashing yellow arrow.

You are reading the signal correctly. With such a display, oncoming traffic has a circular green and a green left turn arrow.

But it is not creating yellow trap. It is preventing it by extending the permissive turn period until it is safe to end it.

The new flashing yellow arrow signals would show a flashing yellow arrow to mean the same thing, but no louvers or shielding are necessary.

[crbcrbrgv]

Flashing yellow arrows sounds like something you could buy at a Phish concert.