U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > U.S. Forums > Texas > San Antonio
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
Reply Start New Thread
 
Old 03-11-2011, 11:19 PM
 
1,040 posts, read 782,393 times
Reputation: 740

Advertisements

There was plent8y of notice in the newspapers. I have seen them online. They explained the meaning of the flashing yellow arrows.

I know of only a few accidents at flashing yellow arrows signals caused by drivers disobeying the signals. They fall into two categories:
- Cheating drivers trying to get through a green light that already ended.
- Drivers from states that have not yet adopted flashing yellow arrows. They are following the old law on flashing yellow arrows meant for when the signal flashes at night. Those laws are ambiguous on the meaning. Many drivers wrongly read them as protected turns.

Last edited by Troubleshooter; 03-11-2011 at 11:46 PM..
Rate this post positively Reply With Quote Quick reply to this message

 
Old 03-11-2011, 11:33 PM
 
1,040 posts, read 782,393 times
Reputation: 740
Quote:
Originally Posted by ged_782 View Post
I'm not familiar with that intersection, but I've noticed at some of the traffic light-controlled intersections I frequently use, there is a sequence to green light cycles - and I've gotten to know at what point I should be getting a green light, based on what direction has the green light when I arrive at the intersection.

At some intersections, I've noticed if I pull into the left turn lane at a point that is too late in the sequence, it will skip the "normally scheduled" left turn cycle, and I will have to wait through the entire cycle again before I get a green arrow. This only seems to happen in dedicated left turn lanes with a "left on green arrow only", no solid green, and no flashing yellow arrow.
Information on this:

- All signals go though preprogrammed cycles. But many of them can skip a green light if no traffic is waiting to use it.

- You have to arrive at the stop line before the green light ahead of yours in the cycle turns yellow. Once that signal has turned yellow, the signal controller must have already decided which signals will be green next. If you weren't there yet, you have to wait a full cucle.

- In a coordinated system, the signal can not change to yellow on the main thorofare until the proper time in the coordination plan. Here is where you see signals sitting there green for the main road with no traffic using that road. This is because the signal must wait for traffic that other signals are supposed to have sent toward it, whether such traffic is there or not.

- Where traffic is highly variable, the coordination plan for that time must be based on the worst case traffic demand.

- Since pedestrians are usually given fixed intervals, the signal must remain green for one street until those pedestrian intervals time out.

- The flashing yellow arrow (when not omitted as below) always flashes whenever the oncoming signal is circular green. This tells you the oncoming signal is circular green.

- The green arrow appears only when the oncoming signal is circular red.

- A time clock can be used to make the signal omit either the flashing yellow arrow or the green arrow, depending on the expected traffic conditions at that hour. One signal near my house omits two of the green arrows during rush hour. Others omit the green arrows at night, when traffic is sparse. Some omit the flashing yellow arrows when traffic is too dense to turn through it.

- Some flashing yellow arrow signals have no green arrow installed, or have a disconnected green arrow lens. These are used solely to prevent yellow trap caused by pre-emptions, or by left turn signals facing the other way. They do not grant protected left turns.
Rate this post positively Reply With Quote Quick reply to this message
 
Old 03-12-2011, 07:18 AM
 
1,040 posts, read 782,393 times
Reputation: 740
Quote:
Originally Posted by TowBar View Post
I did see this on the news a while back. Don't remember when, but it seems like months.

I agree that they don't always seem good. I noticed when turning off of Marbach onto Ellison, the yellow blinking light is long, it it seems to go before the grren arrow. I would expect the green arrow first, then the blinking yellow.
The flashing yellow arrow flashes ALL of the interval when the oncoming circular green is on. It must do this to prevent yellow trap.

One advantage of the flashing yellow arrow is that the green arrow can be safely placed either before the flashing yellow arrow, or after it. This allows engineers to progress green lights from intersection to intersection on more streets. With the circular green permissive turn, the green arrow must always be before the circular green, to prevent yellow trap.

Quote:
On the other hand I wish there was one at Wurzbach and Exchange Parkway. That turn light seems to be defective. I have set there for two or three light changes and the turn light always stayed red. The whole time there were periods where there was no oncoming traffic. The last time I was there I waited through a few light changes, and just ran the red turn light hoping no cops were around.
This can be caused by several things:

1. You drove up past the stop line painted on the road. The stop line tells you to stop where the detector is, so you will activate it. Most detectors detect metal, not motion. If you drive off the detector, it no longer reports your presence to the signal. The signal assumes that you turned right on red or changed lanes, and forgets about you.

2. The left turn might be prohibited for certain times of day. The detector will be turned off by a time clock during that period. But there should be a sign indicating this.

3. Your vehicle is not activating the detector properly. The loop detector buried in the road needs a certain amount of metal directly over it. Bicycles, small motorcycles, and cars made of fiberglass or plastic have problems here. Television detectors see bikes and motorcycles just fine, but some cars have colors of paint that match the road at infrared wavelengths, fooling the detectors into not seeing them.

4. The detector may be broken. Report it to the traffic authority responsible for the signal.
Rate this post positively Reply With Quote Quick reply to this message
 
Old 03-12-2011, 07:50 AM
 
1,040 posts, read 782,393 times
Reputation: 740
Quote:
Originally Posted by curtisntex View Post
What I think is dumb, is having an arrow of ANY color other than green, I hate the red arrows too. An arrow should always mean your protected.
Actually, this has never been true. Until the mid 1960s, different places had different meanings for different colors of arrows:

- New York used a white arrow for protected left turns in the 1930s. Some places in Pennsylvania used a circular purple light for this.

- Illinois and Missouri used green arrows to indicate that the cross street was one way in the direction of the arrow. A protected turn was not defined.

- Indiana used a green arrow for a protected turn, and a steady yellow arrow for a permissive turn. Signs were used to indicate whether or not permissive turns were allowed on circular green.

- Missouri used a steady or flashing red arrow to indicate that a turn was required to be made by all traffic.

- Quebec used the green arrow to indicate that a turn was required to be made by all traffic. They flashed the circular green to indicate a protected turn. But this meant that only one direction could have a protected turn.

- Illinois used the flashing yellow arrow to indicate what it means today. You may turn through gaps in traffic. They used the flashing red arrow to indicate that a turn was required to be made by all traffic after a stop.

The present definitions of all but the flashing yellow arrow were standardized in 1971.
Rate this post positively Reply With Quote Quick reply to this message
 
Old 03-19-2011, 07:14 AM
 
543 posts, read 918,544 times
Reputation: 615
OK yesterday I encountered a new problem which may or may not be the result of these "new" blinking yellow turn lights. I was approaching an intersection (again Marbach/Ellison with the extremely long yellow turn light) and saw the turn light was green. There were two cars already in front of me in the turn lane. Since the turn light was green, I figured I wouldn't need to stop but merely slow down to make the turn. Well the first car pulls into the intersection and stops like he is going to yield to the oncoming traffic (which obviously has a red light), so this makes me have to brake hard and say to my wife, "why is he stopping"? He then figures out he has the right of way, and proceeds through the intersection with his turn. I was still a few yards back as I always allow plenty of space between myself and the vehicle in front of me. So what happens next? The car in front of me does the very same thing, he pulls towards the intersection and stops to yield to the oncoming traffic, which obviously has a red light. I again have to brake hard (actualy had to come to a complete stop at this point) and honked my horn at him. I rarely honk my horn at drivers, as I don't like it when people honk at me. The only reason I can figure that these drivers stopped at the green turn lights is they are confused by the way these new turn lights operate.
Rate this post positively Reply With Quote Quick reply to this message
 
Old 03-21-2011, 10:19 AM
 
1,040 posts, read 782,393 times
Reputation: 740
Quote:
Originally Posted by TowBar View Post
OK yesterday I encountered a new problem which may or may not be the result of these "new" blinking yellow turn lights. I was approaching an intersection (again Marbach/Ellison with the extremely long yellow turn light) and saw the turn light was green. There were two cars already in front of me in the turn lane. Since the turn light was green, I figured I wouldn't need to stop but merely slow down to make the turn. Well the first car pulls into the intersection and stops like he is going to yield to the oncoming traffic (which obviously has a red light), so this makes me have to brake hard and say to my wife, "why is he stopping"? He then figures out he has the right of way, and proceeds through the intersection with his turn. I was still a few yards back as I always allow plenty of space between myself and the vehicle in front of me. So what happens next? The car in front of me does the very same thing, he pulls towards the intersection and stops to yield to the oncoming traffic, which obviously has a red light. I again have to brake hard (actualy had to come to a complete stop at this point) and honked my horn at him. I rarely honk my horn at drivers, as I don't like it when people honk at me. The only reason I can figure that these drivers stopped at the green turn lights is they are confused by the way these new turn lights operate.
Was this intersection converted from one with nothing but permissive turns on the circular green light? If so, those drivers may not have noticed the left turn signal, and are waiting for the circular green on the straight ahead lane signals.

Another possibility is that they are elderly drivers set in their ways.
Rate this post positively Reply With Quote Quick reply to this message
 
Old 03-21-2011, 10:35 AM
 
543 posts, read 918,544 times
Reputation: 615
Quote:
Originally Posted by Troubleshooter View Post
Was this intersection converted from one with nothing but permissive turns on the circular green light? If so, those drivers may not have noticed the left turn signal, and are waiting for the circular green on the straight ahead lane signals.

Another possibility is that they are elderly drivers set in their ways.
No, this intersection used to have the "standard" turn arrow light at it. Also these were young people.
Rate this post positively Reply With Quote Quick reply to this message
 
Old 06-28-2011, 11:44 AM
 
1,040 posts, read 782,393 times
Reputation: 740
I found a clarification on the true reason why flashing yellow arrows are being used:

- For the left turning driver, the flashing yellow arrow has the same meaning the circular green has.

- For drivers who are not turning left, the flashing yellow arrow has a meaning totally different than the meaning of the circular green.

This difference is the reason the flashing yellow arrow was invented.
Rate this post positively Reply With Quote Quick reply to this message
 
Old 06-28-2011, 11:51 AM
Bo Bo won $500 in our forum's Most Engaging Poster Contest - Tenth Edition (Apr-May 2014). 

Over $104,000 in prizes has already been given out to active posters on our forum and additional contests are planned
 
Location: Ohio
17,105 posts, read 36,557,254 times
Reputation: 14433
Quote:
Originally Posted by Troubleshooter View Post
I found a clarification on the true reason why flashing yellow arrows are being used:

- For the left turning driver, the flashing yellow arrow has the same meaning the circular green has.

- For drivers who are not turning left, the flashing yellow arrow has a meaning totally different than the meaning of the circular green.

This difference is the reason the flashing yellow arrow was invented.
Don't you have that backwards?
Rate this post positively Reply With Quote Quick reply to this message
 
Old 07-01-2011, 12:41 PM
 
1,040 posts, read 782,393 times
Reputation: 740
Quote:
Originally Posted by Bo View Post
Don't you have that backwards?
No, I do not.

---

For the left turning driver:

- A steady circular green means you can turn left through gaps in oncoming traffic. This is on a signal with no left turn arrows provided, or on a 5-light left turn face.

- A flashing yellow arrow means you can turn left through gaps in oncoming traffic.

Both give the left turn driver permissive turning.

---

For the driver who is not turning left:

- A steady circular green means you can go.

- A flashing yellow arrow means you have to look at the other signals provided for straight and right turn traffic to see what to do..

These drivers get very different signals from the circular green and the flashing yellow arrow. This is the reason the flashing yellow arrow was created. It totally separates the left turn movement from the straight and right movements in time. They can be independently started and ended at different times in the signal cycle if the flashing yellow arrow is used.
Rate this post positively Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply
Please update this thread with any new information or opinions. This open thread is still read by thousands of people, so we encourage all additional points of view.

Quick Reply
Message:


Settings
X
Data:
Loading data...
Based on 2000-2020 data
Loading data...

123
Hide US histogram


Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > U.S. Forums > Texas > San Antonio
Similar Threads

All times are GMT -6.

© 2005-2023, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Contact Us - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37 - Top