The Vienna Convention pre-green indication

[Pink Jazz]

According to the Vienna Convention on Road Signals and Signs, such nations who have ratified it use a pre-green indication consisting of both the red and yellow lights on at the same time.

The MUTCD gives a reason why they don't allow any pre-yellow indications (such as the flashing green phase used in Mexico and some other Latin American countries), but does not make any mention of pre-green indications at all.  Does anyone have any such idea why pre-green indications are not allowed by the MUTCD?

[Revive 755]

Off the top of my head, I think it is because of concerns for drivers going the instant the light turns green and not waiting for anyone on the cross street who was pushing the light or slow to clear the intersection (such as left turners waiting for the red light to stop the opposing through movement before turning).  Granted you can still get this effect when drivers watch the side street indications.

[M3019C LPS20]

The possible reason above sounds plausible.

Interestingly enough, back in the old days, when four-way heads were dominant throughout the country, a lot of municipalities used the overlap (red and amber lit before green). The other common overlap was the change from green to red. The amber signal appeared lit, and both the green and amber sections were lit for a couple of seconds.

[M3019C LPS20]

I will also say this overlap was probably adequate to use over 50 years ago, since many vehicles had manual transmissions. The indication was an ideal way for a motorist to prepare to change gears prior to the illumination of the green signal.

It is a rather popular belief among a lot of people.

[Pink Jazz]

I will also say this overlap was probably adequate to use over 50 years ago, since many vehicles had manual transmissions. The indication was an ideal way for a motorist to prepare to change gears prior to the illumination of the green signal.

It is a rather popular belief among a lot of people.

This sounds quite understandable.  Manual transmissions are more popular in Europe than they are in the United States, so perhaps this could be why Vienna Convention countries continue to have a pre-green phase.

[vdeane]

I will also say this overlap was probably adequate to use over 50 years ago, since many vehicles had manual transmissions. The indication was an ideal way for a motorist to prepare to change gears prior to the illumination of the green signal.

It is a rather popular belief among a lot of people.

I wish we had a pre-green phase for that reason.  Because we don't have one, I can only take the clutch out of gear at intersections I know well.

[theline]

My father (b. 1913, d. 1974) told me that, once the amber phase was introduced when he was young, that amber was displayed in all directions as the signal switched between green and red (or between red and green). He said this led to many accidents as some drivers would try to beat it, so they were switched to the current arrangement.

[jakeroot]

I would love to see a pre-green phase (red-amber lit followed by green) but I don't think we (the drivers of manual vehicles) could convince the FHWA that there's enough manual drivers still out there to warrant the change. Though we could make the argument that people who are doing other things while they are driving (like texting or changing the radio station) would benefit from having a pre-green phase (they could see the amber in their peripheral vision and could set things down before everyone starts honking). I'm part of the minority that believes that we cannot stop people from texting, etc. In other words, we have to work with them.

[vtk]

Some drivers, approaching an intersecting they think will soon turn green, will attempt to time it so they reach the intersection just as it changes without slowing down much, if they have enough information to judge the timing. A pre-green phase would facilitate that, and I suspect the feds would prefer to discourage this behavior.

[jakeroot]

Some drivers, approaching an intersecting they think will soon turn green, will attempt to time it so they reach the intersection just as it changes without slowing down much, if they have enough information to judge the timing. A pre-green phase would facilitate that, and I suspect the feds would prefer to discourage this behavior.

I think that the best way to avoid that would be to wait until the cross-traffic was red to initiate the red-amber phase. That way, should someone punch into the intersection immediately when it turns green, the cross-traffic will have already been stopped for a few moments.

[Brandon]

Some drivers, approaching an intersecting they think will soon turn green, will attempt to time it so they reach the intersection just as it changes without slowing down much, if they have enough information to judge the timing. A pre-green phase would facilitate that, and I suspect the feds would prefer to discourage this behavior.

It's exactly what I do, if I can see the cross street signal.  I'd rather slow and go to 2nd gear than stop and go to 1st.  Better on my clutch that way.

[NJRoadfan]

Some drivers, approaching an intersecting they think will soon turn green, will attempt to time it so they reach the intersection just as it changes without slowing down much, if they have enough information to judge the timing. A pre-green phase would facilitate that, and I suspect the feds would prefer to discourage this behavior.

People already do that by looking at the countdown timers for pedestrian signals to beat the yellow light.

[M3019C LPS20]

Some drivers, approaching an intersecting they think will soon turn green, will attempt to time it so they reach the intersection just as it changes without slowing down much, if they have enough information to judge the timing. A pre-green phase would facilitate that, and I suspect the feds would prefer to discourage this behavior.

People already do that by looking at the countdown timers for pedestrian signals to beat the yellow light.

Sometimes, though, they end several seconds prior to the change from green to amber.

[briantroutman]

In my experiences driving in London, most drivers quickly put their cars into gear and begin accelerating during the red-yellow phase, and they're already well into the intersection by the time the light turns green anyway. So red-yellow becomes a de facto green, and green is left for laggards.

[riiga]

The red-yellow phase is very short though, so they can't really go more than a few meters into the intersection before it turns green if they're really aggressive. Not all Vienna Convention countries use a red-yellow phase though. The Netherlands used the same phase as the US (Red->Green->Yellow->Red) while I visited there, unless I'm mistaken. And Sweden (and a few other countries (Italy I think)) used to have green-yellow when switching back to red instead of yellow. Overall I'm for using a pre-green indication, but then again there's not really that much need for it when not driving manuals, which is the case in the US. Also, the US has a few unique or MUTCD-specific light types such as flashing red light, flashing yellow in normal operation, etc. Not sure if any of those could conflict with pre-green indication.

For illustrative purposes, pan-European or Vienna Convention signal sequence:

[Brandon]

Some drivers, approaching an intersecting they think will soon turn green, will attempt to time it so they reach the intersection just as it changes without slowing down much, if they have enough information to judge the timing. A pre-green phase would facilitate that, and I suspect the feds would prefer to discourage this behavior.

People already do that by looking at the countdown timers for pedestrian signals to beat the yellow light.

I do that to figure out when the signal will change in Chicago so I can avoid Rahm's Revenue Machines.

[Pete from Boston]

I will also say this overlap was probably adequate to use over 50 years ago, since many vehicles had manual transmissions. The indication was an ideal way for a motorist to prepare to change gears prior to the illumination of the green signal.

It is a rather popular belief among a lot of people.

I wish we had a pre-green phase for that reason.  Because we don't have one, I can only take the clutch out of gear at intersections I know well.

Or you can do what I do, and not worry about the impatient $&@%# that can't wait the one second it takes me to put the car in gear.  Most folks behind me seem to handle this just fine.  The ones that honk were going to honk anyway.  Life's too short to let jerks under one's skin.

[vdeane]

Some drivers, approaching an intersecting they think will soon turn green, will attempt to time it so they reach the intersection just as it changes without slowing down much, if they have enough information to judge the timing. A pre-green phase would facilitate that, and I suspect the feds would prefer to discourage this behavior.

Indeed.  The people who make driving laws seem to like to make driving as annoying as possible.

[TEG24601]

Off the top of my head, I think it is because of concerns for drivers going the instant the light turns green and not waiting for anyone on the cross street who was pushing the light or slow to clear the intersection (such as left turners waiting for the red light to stop the opposing through movement before turning).  Granted you can still get this effect when drivers watch the side street indications.

We already have enough of that with people jumping the left turns.  I'm not pointing fingers, but when I was living in Michigan, it was nearly always someone with an Ohio plate.

[M3019C LPS20]

I do not intend to go off topic, but I thought this would be interesting to share to those that are unaware of it.

As I recall, in some towns of Massachusetts, some vehicular heads that serve as pedestrian signals show a movement that is identical to the "Barnes Dance." This, of course, occurs when all directions of vehicular traffic are red.

Red and amber are both illuminated for a couple of seconds, and this indicates pedestrians have the right-of-way. The amber signal terminates, which ends the pedestrian movement. It is an old movement that is no longer adequate to use today.

This video below shows an intersection there that supposedly continues to use this as of present day.

[cpzilliacus]

The red-yellow phase is very short though, so they can't really go more than a few meters into the intersection before it turns green if they're really aggressive. Not all Vienna Convention countries use a red-yellow phase though. The Netherlands used the same phase as the US (Red->Green->Yellow->Red) while I visited there, unless I'm mistaken. And Sweden (and a few other countries (Italy I think)) used to have green-yellow when switching back to red instead of yellow. Overall I'm for using a pre-green indication, but then again there's not really that much need for it when not driving manuals, which is the case in the US. Also, the US has a few unique or MUTCD-specific light types such as flashing red light, flashing yellow in normal operation, etc. Not sure if any of those could conflict with pre-green indication.

Finland has pre-green indications - they seem to be especially common at protected-phase left turn signals.

[GaryV]

Off the top of my head, I think it is because of concerns for drivers going the instant the light turns green and not waiting for anyone on the cross street who was pushing the light or slow to clear the intersection (such as left turners waiting for the red light to stop the opposing through movement before turning).  Granted you can still get this effect when drivers watch the side street indications.

We already have enough of that with people jumping the left turns.  I'm not pointing fingers, but when I was living in Michigan, it was nearly always someone with an Ohio plate.

That's because the native Michigan drivers know the "one last fool" maxim - after the light turns red, one last fool will go through it.  Those Ohio drivers jumping the green to make a left didn't know how lucky they were not to be smashed by the fool.

[TEG24601]

Off the top of my head, I think it is because of concerns for drivers going the instant the light turns green and not waiting for anyone on the cross street who was pushing the light or slow to clear the intersection (such as left turners waiting for the red light to stop the opposing through movement before turning).  Granted you can still get this effect when drivers watch the side street indications.

We already have enough of that with people jumping the left turns.  I'm not pointing fingers, but when I was living in Michigan, it was nearly always someone with an Ohio plate.

That's because the native Michigan drivers know the "one last fool" maxim - after the light turns red, one last fool will go through it.  Those Ohio drivers jumping the green to make a left didn't know how lucky they were not to be smashed by the fool.

I will say, I certainly miss the flashing red for left turns in Michigan, then completing the turns at the end of the phase.  It makes so much more sense than the traditional convention of having left turns go first, and the flashing red reminds people to stop, usually, before making their turns.

[vdeane]

I always aim to start moving the instant the light turns green.  It annoys me that most Albany drivers take their sweet time about it - I'll be all the way across the intersection before the person in the other lane starts moving, and they always wait for the lead car to clear before they begin accelerating, even if it's clear there are no obstructions to traffic up ahead.  There's also the common situation where someone will stop to let an entire line of cars out of a parking lot (ironically, this behavior makes itself required by creating the backups that cause the line of cars to have to wait to get out of the parking lot in the first place!).  Traffic would flow a lot better if only people would MOVE.

[theline]

Agreed. The first person in line at the red light is the de facto captain of the line. It is his responsibility to pay full attention to the signal and get his butt moving when the light turns green. Especially when I'm the captain, I take my responsibility seriously. It's only common courtesy to do so.