FYA - WHAT IS CORRECT?
A table of whether or not pairs of flashing yellow arrow signal faces must be used on any one road.
*Other methods must be used to prevent yellow trap.
† An offset intersection is two T intersections very close together. The road that is not offset must have yellow trap protection if the first intersection is on the left, or if either intersection has a left turn signal.
Preemptions include emergency vehicle, railroad, drawbridge, and queue discharge. The proper design must be used to prevent yellow trap. Yellow trap must not occur during preemptions.
Intersection with 5 or more legs usually can't have permissive turns. Simultaneous multiple turns into or from the same leg, and multiple oncoming movements make permissive turns dangerous. Left turns must usually be protected or diverted, except if one leg is offset from the others.
Little yellow trap is when the circular greens for both directions end at the same time, but the circular yellows do not. The yellow clearance intervals of the two circular green phases are set to different values.
Green trap happens when opposite circular greens on the same road have their own phase units, but no other phase units are in the concurrency group. The problem happens when one phase stays red until a car appears on the approach.
Each flashing yellow arrow prevents the yellow trap caused by the circular green and green arrow facing the other way on the street.
Even if only one direction of flow has a green arrow, the flashing yellow arrow is needed in both directions.
This 6-indication signal face may be used only if flashing yellow arrow is used in combination with lane use control. The 6 aspects are:
Different rules apply in cases where left turns are currently in exclusive or shared lanes:
If lane use control is not being used, the flashing yellow arrow must NOT be used in a shared signal face.
This is the worst way to install a flashing yellow arrow. It causes the same yellow trap the circular green causes.
In order for the flashing yellow arrow to prevent yellow trap, the flashing yellow arrow must be tied to the oncoming circular green, not the circular green facing the same way the flashing yellow arrow faces. The circular green facing the same way has the wrong timing, causing yellow trap.
People from those states got into accidents when they saw flashing yellow arrows while driving in other states. But all such installations should have been removed by 2003.
Any case (including acute angle turns) where it takes longer for the driver to make the turn than he thinks it will take must not have permissive turns. Exclusively protected signals must be installed.
If the exit of the turn is not readily visible due to vertical alignment or obstructions, the turn must not be permissive.
A study showed that most drivers looking for gaps in heavy oncoming traffic don't look for pedestrians in the left hand crosswalk before turning through a small gap. They recommended inhibiting the flashing yellow arrow while a pedestrian phase is timing.
This will cause third yellow trap if the phase is reserviced to serve a pedestrian pushbutton call with no calls on cross street phases.
If the flashing yellow arrow is inhibited for pedestrians, reservicing the phase must also be inhibited. Otherwise, the flashing yellow arrow must not be inhibited.
The flashing yellow arrow can be inhibited by time of day, provided that the time-of-day switching occurs while the left turn signal shows a red arrow.
Flashing yellow arrows can not be used where any of the following conditions exist:
Even if the flashing yellow arrow is not allowed to be installed, the approach must still be protected against yellow trap. Other methods must be used to prevent yellow trap.
The pre-emption must not be designed to protect government employees in an emergency vehicle at the expense of safety to other drivers. The flashing yellow arrows must be displayed on the leg oncoming to the leg getting the priority green.
Politicians tend to want to protect the government employees driving a police, fire, or medical emergency vehicle at the expense of the safety of other drivers.
Because they want to favor their employees, they demand a design that cuts off three approaches and gives an exclusive green to the leg with the emergency vehicle. But this causes yellow trap if the phase oncoming to the exclusive phase is cut off by a yellow light for the preemption.
Proper preemption design requires that a flashing yellow arrow must be shown to left turns that would otherwise be cut off, so they are not caught in yellow trap. Otherwise, an all-way-red clearance must precede the exclusive green.
The flashing red lights on the emergency vehicle itself should protect it from the one movement that has the flashing yellow arrow. With the rest of the intersection cleared of traffic, the driver can easily see the emergency vehicle.
If the yellow trap caused by an improper installation causes an accident, the emergency vehicle may be blocked from reaching its intended destination by the accident.
Yellow trap can be prevented through other methods used with permissive turns, but the main advantage of having the flashing yellow arrows is lost. The purpose of the flashing yellow arrow is to prevent yellow trap, and it must be installed correctly to do this.
But the above beliefs are not true. The truth is:
The purpose is to completely separate control of the permissive left turn from control of the straight-ahead traffic.
The flashing yellow arrow can allow the permissive turn to be made while the straight ahead signals are red. The circular green can't do that, because it also tells other movements to go.
The image at right shows the combination of indications that cannot be displayed by a set of signals that has a circular green for permissive turns.
He opened his mouth, just like a typical politician.
Yellow trap occurs when all of these come together at the same signal:
The problem is that each driver thinks a different law applies at the moment:
The problem is that each driver expects the other driver to stop. When the other driver does not stop as expected, the accident occurs.
It is operating correctly. This is the part of the sequence that prevents yellow trap and provides all of the other advantages.
The flashing yellow arrow flashes at all times when the oncoming circular green is lit. This is the only safe and flexible way to remove yellow trap from permissive turns.
When you see that the circular signals are yellow or red and the flashing yellow arrow is flashing, the sequence has protected you from yellow trap. It also shows that the flashing yellow arrow is installed correctly.
There are several different reasons that different signal sequences are needed:
This is a good way to get yourself killed. It's dangerous and illegal.
A flashing yellow arrow face is the only face controlling left turns.
If you can't learn this simple addition to traffic signals, or if you can't drive anywhere signal sequences are different, you do not belong on the road.
A flashing yellow arrow means you can turn through gaps in oncoming traffic.
The federal government has already approved it in the 2009 MUTCD as the preferred left turn signal where it can be applied. Nothing can stop it now.
Most of these stories have no basis in fact.
In a case where an intersection was not suitable for any kind of permissive turn, reporters thought the flashing yellow arrows were the problem, even though turns on circular greens would have produced the same problem. The flashing yellow arrows were removed because of the incompatibility with the permissive green.
In one case, the driver understood the flashing yellow marrow, but did not see an approaching motorcycle.
In another case, a crash was caused by a driver from a state where flashing yellow arrows had been used with a different meaning many years ago. The elderly driver misunderstood the flashing yellow arrow, even though a sign explained the meaning. He used the meaning his state had used years ago.
Reporters at a TV station blamed the flashing yellow arrows for every accident at a signal where they are installed, including the two cases immediately above this paragraph.