Sunday 5 December 2010
One of the improvements suggested, which should be done, is to remove all supplementary plates e.g. "One way" or "Dual carriageway".
The other improvement suggested is to suggest new signs to prescribe: Mandatory left or right turn (you cannot go straight ahead), mandatory straight or left turn (i.e. no right turn), mandatory straight or right turn (i.e. no left turn). These would not replace existing no left turn or no right turn signs. Similar filter arrows for traffic lights could also be considered in future.
Examples to illustrate are shown in this article.
Remove unnecessary supplementary plates
This is another area where removing unnecessary supplementary plates (in this case "One Way" or "Dual Carriageway" removes clutter. Hundreds of thousands of these type of supplementary plates could exist in the UK, so there can be maintenance savings. This is illustrated below:
Removal of redundant supplementary plates for mandatory direction signs.
Furthermore, there is no need to tell the road user we are on a One Way street or a Dual Carriageway. It should already be obvious that we are on a One Way street or a Dual Carriageway, all we need to know is which direction is mandatory. The superfluous supplementary plates should be removed completely.
Suggested new signs
The three suggested new signs below are not currently prescribed for use in the UK:
Mandatory left turn or right turn sign
Mandatory straight ahead or left turn.
Mandatory straight ahead or right turn.
The latter two signs (straight ahead or left turn, and straight ahead or right turn) would not make "no right turn" or "no left turn" obsolete, far from it. There are situations where it is necessary have "no left turn" or "no right turn" signs, to deter vehicles from entering.
There may be other situations where it makes more sense to use positive instruction instead to say what we, the road user, must do ("left turn or ahead only", "right turn or ahead only", "left turn or right turn only").
Prescribing these signs would give those in charge of the roads more options on which signs can be used. But most importantly, intelligent usage of the available signs can reduce the amount of signs needed, and as a result (more importantly) information overload.
Traffic lights - left or straight, right or straight filter lights
Whether or not the new signs above in "Suggested new signs" be introduced, there can be the option of having filtered traffic lights which have either "left or straight", or "right or straight" filter arrows similar to those in the signs above (in addition to the existing filter arrows). There would be no need to alter existing traffic lights, but this would be something to consider for future traffic lights. There are also some cases where we do wish for left turn to be separate from straight ahead in the traffic lights.[UPDATE: With the exception of the traffic lights subsection, the rest of this article has been deprecated and superceded by another article here]
Hi there,
ReplyDeleteAnother interesting article, although there is a reason we use the (at first glance wasteful) supplentary plates with a mandatory movement arrow sign.
You're allowed to legally pass traffic on the left on a one way road (without invoking the 'passing slower traffic on the right' exemption), but not on a dual carriageway. This is therefore referenced in the mandatory sign so entering traffic knows there may be faster moving traffic in the left hand lane.
I dare say, somewhat controversially, if we scrapped the rules about passing on the left and encouraged wiser use of all road space on multi lane roads we could abolish the plates altogether.
You must turn left/right AND go straight ahead? What would be the point of these signs in a typical application when a simple No Right/Left Turn would be appropriate?
ReplyDeleteAnd what function would the "must turn left and right" sign achieve that existing signage cannot?
The supplementary plates "One Way" and "Dual Carriageway" also have legal meaning, because the National Speed limit differs on a one-way road and a dual carriageway.
ReplyDeleteIn addition, there are some TWO way streets where it is illegal to enter from a certain direction but you can exit from both (so drivers exiting from fronting properties can go both ways, but you can't enter from one end, to prevent a road being used as a rat-run). I would imagine there are situations when you would want to force drivers down a certain road (e.g., you must turn right), but in fact the road you are turning on to is not a one-way road, so there could be cars coming the other way, and you can do a three-point-turn if you need. So the supplementary plates are a necessity to inform the driver what the legal status of the road is that he will be turning on to.
To distinguish between a dual carriageway and one way street, a sign like this could be used...
ReplyDeleteOne Way Sign
That's a US example, but I'm aware that you don't seem to like text very much, so the text could possibly be omitted, like in the Canadian version. Some European countries also use this sign, including Germany, where the text reads 'Einbahn'.
Hi All,
ReplyDelete@Bryn and Anonymous (9 December 2010, 21:56) - Thank you both for your explanations, it is not obvious at first why they are necessary or that the plates have a legal status. These supplementary plates for One Way or Dual Carriageway can be retained. Or another alternative is to have a different sign for One Way (as suggested by Gareth).
@Anonymous (8 December 2010 16:51) - The signs "mandatory left or straight", "mandatory right or straight", and "mandatory left or right" are only suggestions, and for me totally optional. They don't have to be introduced, are certainly not needed to comply with the Vienna Convention, so I don't mind one way or the other. These arrows do already appear on road markings, indeed some towns have "mandatory left or right" road markings where you have to turn either left or right.
@Gareth - That's an interesting suggestion, and thank you for sharing this. Indeed we can consider using a sign similar to the one you showed used for One Way to the left (or right, depending on direction) - a similar design exists for one way (as opposed to mandatory ahead). You're right, I'm not a big fan of text on signs, and think that if something can be expressed symbolically without text it should be. Having said that, there might be some circumstances where it is unavoidable, or where simple text can be used (One Way would be such a simple text so can be considered in this case), but I think wholly symbolic is preferrable where possible.
I will be revisiting this topic in a future article.
I do wonder - why can't we have traffic lights with directional arrows on the red and amber phases as well as green? It would clarify some particularly confusing sets around my local area, for a start, where there is, e.g.
ReplyDelete1. A straight-ahead-only and turn-right-only set of undivided filter lanes on a dual carriageway, which are either all-red, green-ahead and red-right, or all-green. But until you are reasonably close up, the shape of the road and passing tall traffic can make it hard to tell what state they're in, and if you should maintain cruising speed for the straight-ahead direction, or prepare to stop.
2. A strange semi-roundabout layout at the entrance to a shopping centre, on (in the relevant travel direction) the right of a short technically dual-carriageway section (single carriageway with a 25-metre long lump of concrete and some lights in the middle). The straight ahead direction is unobstructed and ALWAYS green... which shouldn't need a light... but because the right turn is light controlled, and without a right-pointing red and amber, they have to include an always-lit up-arrow offset to the left of the other lights. Bonkers.
That and flashing amber all directions for a more major junction not far from it, where you can be sat 2 or 3 minutes in the dead of night at a red, because they never bothered to activate the vehicle sensors that even some much more minor 4-way crossings have in the same area. As you can see what's coming quite easily, I've taken to just inching carefully across on red rather than wasting time and fuel...
@Tahrey - Thank you for your comment, good point regarding the left-or-straight and right-or-straight filter light. I favour the introduction of these and hope to introduce some graphics to an existing article (as an update).
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