Signage improvements: Diversion and advisory routes

This article suggests changes (and new signage) to modify and improve diversion and advisory route signage, by making them wholly symbolic and language independent as well as metric, which can benefit safety by making the signs easier to read at a glance.  Of course the bare minimum is to leave the designs as is and just metricate. 

I believe however that we can do better, and make the signage more symbolic at the same time, where applicable.  As with all the previous articles in the "Signage improvements" series, examples are given in this article as well. Also stated in this article is where changes are not required, for example recommended lorry routes, many diversion signs, and many signs showing routes avoiding restrictions (such as no left turn), do not require change.

Advisory routes for lorries

Advisory routes for lorries should remain unchanged, it is good as it is.  The colour scheme could potentially be improved (e.g. use navy or a more aesthetically pleasing colour instead of black), but I suggest leaving the colour scheme as it is.

Signs which incorporate advisory routes for lorries, and standalone advisory routes for lorries are shown below, for completeness:

Signs showing advisory routes for lorries. These should remain unchanged.

Suggested new advisory route and diversion symbols

What I would suggest is extending the notion of advisory routes to lorries over a certain mass, vehicles over a certain mass, vehicles over a certain height, over a certain width, and so on.  At the same time new symbols are also suggested.  I would also suggest allowing diversion signs to use these symbols, with its own colour scheme.

The suggestions are shown below:

Advisory route symbols, Diversion route symbols, and the restrictions these avoid.
Shown here for lorries over 3.5t, lorries over 7.5t, vehicles over 7.5t,
and vehicles with a mass of over 4t per axle.

Advisory route symbols, Diversion route symbols, and the restrictions these avoid.
Shown here for overheight, overly wide, and overly long vehicles.

Advisory route symbols, Diversion route symbols, and the restrictions these avoid.
Shown here for vehicles carrying marked hazardous materials (e.g. highly flammable or toxic materials), and vehicles carrying more than 3000L of water pollutants.

Example usage of advisory route symbols (current and suggested)

Examples of the advisory / recommended route symbols in usage (current and proposed) are shown below:

Examples of advisory routes, not only for lorries (which currently exists),
but for other types of vehicles too.

More examples of advisory routes.

Examples for diversion signs are shown in the subsection "Examples using suggested new diversionary symbols".

Existing emergency diversion symbols can remain unchanged

You might be familiar with the diversionary symbols, for example the filled triangle, square, circle, diamond and the unfilled versions of the same shapes.  These are used to give an alternative route in the event of an emergency where the motorway or primary route (for example) has to be closed.  These do not need to be changed, examples are given below for completeness:

Existing emergency diversionary symbols. No change required.

One change that could be considered is to classify the diversions with a number, and to superimpose the number on the symbol.  Classified diversions could help in journey planning, but I don't think classifying diversions is that important, so I have not provided examples of classified diversions for the moment.

Diversion direction signs can also remain unchanged as shown below:

Diversion direction signs. In general no change required.
However, "Diverted traffic" could be replaced with "Diversion".

Having said that, as a minor point, I would suggest that the words "Diverted traffic" could be replaced with the single word "Diversion".  In general the wording "Diversion" can be retained, the words are kept to a minimum.  An example of this is shown below:
 

Replacement of "Diverted traffic" with "Diversion".

However, end of diversion should have unnecessary wording removed.  Whether it is the end of the symbolic emergency route, or an end of diversion, a red slash should be used to signify this is the end of the diversion.  This is straightforward and can be understood internationally (even if the word "Diversion" is language specific but that is not a major issue).  Examples are shown below:

Suggested end of diversion signage

Instead of saying "Diversion END" or "End of Diversion", one can use more symbolic versions.  The resulting sign can be smaller as a result.

Examples using suggested new diversion symbols

It is suggested to use symbolic diversion signs, as shown in "Suggested new advisory route and diversion symbols", for lorries, overheight vehicles, and so on, on diversionary signs, or to incorporate them on to directional signs.  Examples of these are shown below:

Example new standalone symbolic diversions, for avoiding height limits
and marked hazardous materials restrictions respectively.
This shows examples with and without a destination.

Similarly, signs for overly wide vehicles can also have unnecessary wording removed, as well as being made symbolic, examples are shown below:

Metrication of wide loads roadworks sign, with further improvements suggested.

A possible way of symbolically saying "Drivers of vehicles wider than 2.9m, phone here".

For the emergency telephone for drivers of wide loads, it should be sufficient just to have a telephone symbol and an actual definition of a wide load (in this case, greater than 2.9m). This should make it clear that the telephone is "here", and that this is for drivers of wide loads greater than 2.9m (which was used in this example).

For the wide loads signage, we can see how wholly symbolic signs are smaller, easier to read at a glance, smaller, and therefore safer to handle in road works situations.  Furthermore minimising or eliminating unnecessary words really does eliminate clutter.

And an example of a symbolic overheight diversion incorporated into a direction sign is shown below:

Symbolic overheight diversion incorporated onto a direction sign.
This way the words "avoiding low bridge" do not need to go on the sign,
and the sign can be language independent.

Symbolic overheight diversion incorporated onto a direction sign (an alternative which incorporates the destination name into the diversion colour scheme too).

Signs with alternative routes to avoid restrictions (mandatory changes)

These signs are well designed and in general only require metrication where applicable.

Indeed many of these type of signs do not require any change, not even metrication (they show no measurements), these are shown below:

Turn prohibited with alternative route shown. No change required here.

By contrast, other signs, such as the signs below only require metrication, although for one of the examples, a possible (optional) redesign is suggested:

Metrication of turn prohibited signs, with a possible optional redesign shown where applicable.

Metrication is all that is sufficient, that change is mandatory.  Note that in the optional redesign, the distance to the diversionary route is shown instead of the distance to the restriction.

Suggested new signs to avoid restrictions

In this subsection, examples are provided for signs that not only show restrictions, but have the diversionary route on a map-style sign.

Sign showing route to avoid a "No vehicles" restriction. In this case,
at 200m turn left, then follow Four Miles and Longacre to reach London.

The example above shows not only that a no vehicle restriction is ahead, but that 200m ahead there is a diversionary route, and that one should follow "Four Miles" then "Longacre" to get to London.

The example above also makes clear that if there were place names like "Four Miles" and "Longacre", they would not change as a result of metrication. The same applies for real life places such as Mile End (in East London), and Three Mile Cross (in Berkshire, near Reading).

The example below shows not only a height restriction, but a diversionary route for overheight vehicles to bypass the restriction and get to London:

Sign showing route to avoid a height restriction. In this case,
at 200m turn left, then follow the route shown to reach London.

And the example below shows not only restriction for vehicles carrying marked hazardous materials, but that 200m ahead, there is a diversionary route which can be used to bypass the hazard and reach London:

Sign showing route to avoid a marked hazardous materials restriction. In this case,
at 200m turn left, then follow the route shown to reach London.

I would also suggest that the routes would still need to be well signposted (without being cluttered) so that motorists can follow the diversions easily.

Escape route sign modifications

Escape route signs, for example to escape a steep hill, or to escape a height restriction, should be made more symbolic. It should be obvious that the sign is an escape route sign, so wording can be eliminated.

Escape lane ahead before and after removing unnecessary wording.
It should be obvious that the sign is for an "Escape lane".

I personally thought the colour scheme could be improved too, with the usage of red instead of black.  But this is a minor cosmetic change.  The important thing is that "Escape lane ahead" looks like unnecessary wording and can be removed.

Restriction signs shown

In this article, there are three restriction signs which may (or may not) be unfamiliar to UK motorists.  One is used in the UK already (no marked hazardous materials allowed, this is used on the Rotherhithe tunnel), the other two (water pollutant restriction, mass limit per axle) are used in most of the rest of Europe but not currently in the UK, these can be introduced into the UK as new prescribed signs without too much controversy. These can be used where there is a benefit, i.e. forbidding marked hazardous materials and/or forbidding more than 3000L of water pollutants, both can be done as environmental protection measures.

The sign forbidding vehicles carrying marked hazardous materials is shown below:

No vehicles carrying marked hazardous materials allowed sign.

The sign forbidding vehicles carrying more than 3000L of water pollutants is shown below:

No vehicles carrying more than 3000L of water pollutants allowed sign.

The axle mass limit gives the an alternative mass limit which could be used. This was already shown in this previous article. A 4t per axle mass limit is shown below:

Mass limit of 4t per axle.
Note the correct symbol for tonnes, t, should always be used.