Scottsdale's Left-Turn Lights

[observer53]

Originally Posted by KK85297

On another thread she/he recently said that he/she has lived in Gilbert for 3 years and that it's a total dump. It struck me as odd that someone who has lived in this dump for three whole years (longer than me, even!) would not have noticed the lagging arrows....

I think he lives in the Greenway/51 area, based on a recent thread. In "Moving 2 Gilbert", from January) he said he USED to live in Gilbert, perhaps before they adopted the lagging lefts, whenever that was. Either that, or he didn't notice them.

[KarmaPhx]

Originally Posted by LocoAZnative

I wouldn't worry about Karma they seem to just love to stir things up, and make pointless threads. See this one as an example.

They?

How exactly is this a pointless thread?

You're a ignorant ****tard.

[fcorrales80]

Originally Posted by KarmaPhx

They?

How exactly is this a pointless thread?

You're a ignorant ****tard.

With the name calling dude. I think some people just don't understand why you would ask why about green lights. To some it may seem silly, but then who are they to say what is important to others! Don't worry about it, post on! It was a relevant question especially if YOU experience situations were people are often confused by the lagging green arrow; that makes it relevant to you and people with similar experiences.

[CodyW]

Originally Posted by KarmaPhx

They?

How exactly is this a pointless thread?

You're a ignorant ****tard.

AN


You're AN ignorant ****tard.



And man - relax a little, will ya?

[azdr0710]

the lagging left-turn arrows are universal down here in Tucson and are an immensely safer way to handle intersection traffic.....as joninaz says, the city adopted it several years ago to get the main body of thru-traffic on their way......

it is, by far, the safer way to handle a left-turn....

we've all seen the left-turn-arrow-first method and have seen the left turners keep going despite their arrow having gone thru yellow and oncoming traffic now proceeding on their green....really dangerous

[Troubleshooter]

A quick lesson on leading and lagging left turn arrows:

A single lead left turn is where a left turn arrow facing in only one direction, along with the adjacent circular green goes first. The the arrow turns yellow, and afterward, the opposing direction gets a circular green. This combination is safe, unless the cross street green is skipped. Then it causes yellow trap, unless flashing yellow arrows are used in both directions on that street.

A single lag left turn is where a left turn arrow faces in only one direction. Both circular greens on the same street go first. The the circular green facing the opposite direction turns yellow, and afterward, the green arrow comes on. This combination is dangerous unless flashing yellow arrows are properly implemented on that street, or the opposing left turn is prohibited. Otherwise, it causes yellow trap every cycle.

A dual simultaneous lead left turn (or just dual lead) is where left turn arrows facing both directions go first. The the arrows turn yellow simultaneously, and afterward, both circular greens are displayed. This combination is always safe.

A dual simultaneous lag left turn (or just dual lag) is where circular greens facing both directions go first. The the circular indications turn yellow simultaneously, and afterward, both green arrows are displayed simultaneously. This combination is always safe.

A dual split lead left turn is where left turn arrows facing both directions go first. The each green arrow ends separately when it runs out of traffic. After the yellow arrow in each case, the opposing circular green is displayed. This combination is safe, unless the cross street green is skipped. Then it causes yellow trap, unless flashing yellow arrows are used in both directions on that street. This combination is also safe with an all-arrow exclusively protected display, even if the cross street green can skip.

A dual split lag left turn is where circular greens facing both directions go first. The the circular indications turn yellow separately. After the circular yellow in each case, each opposing green arrow is displayed. This combination is safe with an all-arrow exclusively protected display, or when flashing yellow arrows are used in both directions on the street. It is always dangerous if left turns are allowed on circular greens, causing yellow trap.

A dual unsplit lead-lag left turn (also called split-phase) is where the green arrow and the adjacent circular green facing one direction go first. Both indications turn yellow and red simultaneously. Then the green arrow and the adjacent circular green facing the opposite direction go at the same time. This combination is always safe. It is used where progression platoons from opposite directions arrive at very different times, or if the geometry of the intersection prevents opposing left turns from turning simultaneously.

A dual one-split lead-lag left turn (also called split-phase) is where the green arrow and the adjacent circular green facing one direction go first. The arrow ends first, changing to a yellow arrow, and afterward, the opposing circular green is displayed. Sometime later, the circular green on the leading side turns yellow, and afterward, the left turn arrow on the lagging side turns green. This combination causes yellow trap on the leading side when permissive turns are used. It is safe with exclusively protected turns, or with flashing yellow arrows. It is used where progression platoons from opposite directions arrive at very different times, or if the geometry of the intersection prevents opposing left turns from turning simultaneously.

A dual two-split lead-lag left turn (also called split-phase) is where the green arrow and the adjacent circular green facing one direction go first. The arrow and the circular green can end separately when each runs out of traffic, changing to yellow, and then releasing the opposing movement (the end of the green arrow releases the opposing circular green, and the end of the circular green releases the opposing green arrow). This combination causes yellow trap on the leading side when permissive turns are used. It is safe with exclusively protected turns, or with flashing yellow arrows. It is used where progression platoons from opposite directions arrive at very different times and left turn volumes are high.

A triple or quad left turn sequence is a combination of two single or dual sequences, one for each street.

What causes yellow trap is the ending of a permissive left turn before the opposing straight ahead ends.