Safe Speed Forums

Currently traffic lights have 3 states, "stop and wait even if there's nothing else about", "stop unless unsafe" and "you are allowed to proceed".

A lot of the time what we really need is a way of signalling "you have priority", "you don't have priority", and possibly "you are about to loose priority".

The only time we really need an absolute "stop and wait" is on a road where there is only room for 1 vehicle in either direction. (Bridge, roadworks, etc.)

Then there's the question of how to signal these concepts? I have some ideas here:



These are designed to fit in to a standard traffic light so new lenses/filters could be retrofitted onto existing lights as easily as possible. The grey border in each position is to show the size of the existing lens.

I originally posted this on another thread where Paul suggested the give way triangle and stop sign.

Pros and cons of signalling priority rather than stop vs. go?

Pros and cons of different ways of signalling?

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Andrew.

I know in France a flashing amber light is used in the signaling scheme. It is a proceed with caution light. Confused the hell out of me the first time I saw it.

AIUI it is used during quiet times, midnight to 6 or 7 am, in rural towns and villages. I have never seen it in larger towns and cities.

I'm thinking the shapes would need to be sufficiently different so that even in the worst possible weather/visibility conditions, there could be no doubt at all as to whether you were approaching a "give priority" or a "stop without question" set of lights. Perhaps instead use flashing reds/greens to denote "you don't/do have priority" (which is similar to how lights work in some other parts of the world in similar scenarios), and keeping static red/green for times where the lights need to be interpreted exactly as they are at present?

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Chris

The middle one does it for me - triangles for amber and red.

I assume you mean number 4 from the left as even numbers don't usually have a middle...

I kind of prefer number 2, but that is probably only because I designed it.
Number 4 makes the most sense really, and this could be converted to much easier. (without a white border it would be very easy)

I should think the shapes would be recognisable, current 200mm green arrows are thinner and quite recognisable. Except that octagonal stop sign. I don't like the look of it now I've drawn it. Maybe it would look better for real, or with STOP in white across it, but as is it's too similar to a red circle. Or is that a bad thing?

I need to get some UK traffic signals to test these with, especially any with flat lenses. I think the Siemens Helios has flat lenses...

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Andrew.

Yep. Number 4 with the largest possible triangles without the white border.

(When I mentioned white in the other thread, I was thinking standard give way sign - red border on a white triangle. I now think the white is redundant, which is helpful from an engineering point of view.)

Green is 'you have priority' in all circumstances, so we can stay with a circular light at all times.

Red circle at the top is always stop as per now. We'll still need such lights for pedestrian crossings, and (I'm guessing) complex junctions.

Red triangle at the top is: 'give way'.

Amber triangle is: you are about to lose priority.

Red circle is followed by red and amber circles; Red triangle is followed by red and amber triangles. Both cases of red and amber mean prepare to go if it is safe to do so.

Amber circle is as per now - stop if safe to do so.

Retrofitting priority lights could be as simple as adding triangular masks to standard lights, or as complex as whole new sequences with both 'stop' phases and 'give way' phases. In some cases it might be extremely useful to be able to indicate both stop and give way at different times. With LED style modern lights this just means wiring the leds in two groups - 'triangle' and 'the rest'.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

....But wont these relieve congestion?

Oops, yeah, it is the other way round... Guess I failed the theory test there... *ahem*



Yep. I think current traffic light controllers might have a problem switching this, but I guess that just means I'll have to make mine sooner...

I have seen triangular signs on traffic lights (presumably in France) so I guess the technology is there to make them.


Sssh...

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Andrew.

Here's a better diagram of the favourite. I even drew it to scale. (Well, if you had the original or printed this at 72dpi)

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Andrew.

Maybe the flashing amber 'proceed with caution' is just the simplest and best idea?

Slightly OT but what I have seen at times in the US is flashing orange lights to indicate that a traffic light junction is coming up - then when it judges the lights will be red by the time you get there it has a message too.

Something like that would be v useful on fast roads with traffic light junctions.

Ian

No problems in light traffic; after midnight; that sort of thing, but busy urban junctions might well benefit from 'rotating priority'



Yeah. The standard 3 second amber isn't enough on fast roads.

See Safe Speed pr: PR346: Traffic lights: The fast road problem.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Great thinking Ziltro, I like it. But I just wondered why you didn't favour using a square for one of the two triangles?

If I think of three distinctive shapes, which would also help colour blind drivers, would it not be helpful to use circle, triangle and square?

Not trying to rain on your parade.

You made me think of the American word seen at junctions - 'YEILD'. I know it's the same as our 'Give Way' but it's a lovely expression and more concise.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Hmm... Well the current setup of circle, circle and circle doesn't seem to cause any problems. Does it?
The lights are also top, middle and bottom which is fairly obvious too. (Except in london at night where they seem to refuse to use borders?!)

If someone saw the amber and thought it was red then they might stop... Oh no...

Also in Canada they have (I think) triangle, circle, square for green, amber and red, so if it was for that purpose I'd probably follow their idea.

That's all the excuses I can think of. Pick your favourite.

(Or you could say I just didn't think about it...)

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Andrew.

I would go for green in one direction and flashing amber in the other, people "should" already know that flashing amber means they have to give way if someone is using the crossing, so it isn't too great a logical extension that they have to give way to a car on the main road. It also means we don't have to retrofit every traffic light in the country so is much more likely to actually get implemented.

Perhaps we could couple this with a flashing green on the main road to inform drivers who have priority that there is a higher than normal chance of some muppet pulling out in front of them

Flashing amber vs flashing green is a good option.
However this would require the upgrading of the traffic signals controllers. I doubt their current software can actually do this. (Only pelicans do flashing anything, and they are the simplest of all controllers)

So either way something has to be upgraded.

Actually, that way you could have flashing green (and amber) arrows!
Maybe that would be good...

I'm working on a traffic signals controller in my head...

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Andrew.

I'd much rather then mess around in the gray boxes at the side of the road than have them closing off lanes while a "Ladder Trained" engineer climbs up and swaps lenses, much less disruptive and cheaper too. Plus I really think that introducing new symbols is going to confuse people.

As a future expansion you could have flashing orange arrows, for example to only allow you to turn left because there is a blind corner to the left on the main road, therefore you cannot see oncoming traffic and therefore it is never safe to proceed while the main road is on green. I think this situation will be quite rare though, so it's safe to add it in over time the same as we have a lot more filter arrows these days.