|METRICATION: 5% complete|
|Distances shown in kilometres and metres on tourist information signs.||Distances shown in miles and fractions.|
|Sign specifications in millimetres.||Distances shown in yards|
|Sign positioning in metres.||Distances shown in mins.|
In the UK, pedestrian signage has always been the poor relation of signage for motor vehicles. There is no single national standard for pedestrian wayfaring signs, and in many town centres, there is often no pedestrian signage worth speaking of at all.
Finger post signs, or signs that indicate the direction of named locations, usually lack distance information. This greatly reduces a sign’s usefulness and is unhelpful to people who need to decide whether to walk the whole way to a destination, or whether they should use public transport, or hail a taxi.
Where signs have distance information, this is often in miles, or fractions of miles, even though the imperial system of measurement ceased to be taught in schools in 1974. For many people, a mile just means a long way. It is a distance that is difficult to visualise, and as such, fractions of miles become equally meaningless.
Some pedestrian signs show distances in terms of minutes, where one minute walk is the distance travelled in one minute by an able-bodied adult while walking, unhindered by poor weather or crowds.
Less frequently, signs in metres, or kilometres can be found. Where these signs fall outside the remit of the Traffic Signs and General Directions (TSRGD), these are perfectly legal, but the continued existence of a small number of anti-metric activists, means that these can still be prone to criminal damage. That the legality of metric signs has to be mentioned at all, is probably an issue unique to the UK. Despite the UK being a largely metric country, the Department for Transport does not permit the metre or kilometre to be used on pedestrian signs prescribed by the TSRGD.
The metrication of pedestrian signs is long overdue. Whether as part of a new national system of pedestrian wayfaring signs, or as part of a program of upgrading all existing pedestrian directional signage with distances in metric units, the exclusive use of metres, and kilometres will bring the following benefits:
- Pedestrians will finally get to use the units of distance that have been taught in school for 50 years.
- Distances in multiples of 100 metres are easy to visualise – there can be very few people who have never seen a 100 metre race on TV.
- The metre is the world standard unit of measurement for distance.
- The metre is used exclusively on short distance signage in practically every country in the world (apart from the USA).
- 96% of the world’s population live in countries where metres are used to indicate distances on direction signs.
- Distances in metres shown using the standard “m” symbol can be understood in any language.
Distances in minutes
Around 2005, a project called Legible London was set up to create a common wayfinding system for pedestrians in central London and the Olympic Park zone by 2012, extending to the rest of London by 2015. This was a joint initiative between Central London Partnership (CLP), Transport for London (TfL) and the central London local authorities. The aim was to make London a more walking-friendly city.
It had been known for some time that many people avoid walking, even short distances, if it requires them to navigate through unfamiliar territory. This was confirmed by field work, carried out for Legible London, which revealed that some travellers in London were taking the tube for short journeys that would be quicker if they walked. It was postulated that one of the reasons for this could have been lack of access to map information. The lack of pedestrian signs giving clear directional and distance information was also an obvious possibility.
In March 2006, Legible London published their recommendations in Legible London, A wayfinding study.
The study’s preliminary sign audit drew attention to the multiplicity of different signage systems that were in use at the time, and the inconsistency in whether and how distance was communicated, “Only some systems give distances on directional signs (fingerposts) and of those that do there is a varied approach of using either minutes, fractions of miles, metres or yards”.
“Minutes, miles, metres or yards? Across the systems there are inconsistencies which can be confusing for a pedestrian.”
Legible London, A wayfinding study – March 2006
It was not unexpected that the study’s conclusions would recommend the use of a single unit of distance for all pedestrian signs. However, a golden opportunity was missed by not opting for the metre as the standard unit.
Wayfinding signs, Central London – 2008
Instead, the signage system that emerged consisted of map-based signs with distances to locations shown using an improvised unit, the minute walk, which is the distance supposedly travelled in 60 seconds while walking.
A minute walk, by its very nature, is a widely variable distance. However, in order for it to be shown on a map sign, a standard walking speed has to be defined. The speed chosen by Legible London was 80 metres per minute, or 4.8 km/h, which represents a fair walking speed for an able-bodied adult.
Tourist maps of London, distributed during the 2012 Olympic Games, confirm that one minute walk is equal to 80 metres.
1 minute walk = 80 metres
A distance scale showing minutes – London Summer 2012 Map, TfL
At the 2012 Olympic Games, the winning time for the 400 metres, or 5 minute walk, was 43.94 seconds in the men’s event, and 49.55 seconds in the women’s event.
By 2008, Legible London’s new signage system had been installed in many prominent places in central London. The enamelled monolith-style signs feature maps with distance scales in the form of circles. The circumference of the circle labelled “5 minute walk” passes through all the points on the map that are a distance of 5 minutes walk, as the crow flies, from the point marked, “You are here”.
Why was the minute walk chosen as the standard unit of distance?
The decision to adopt the minute walk for all pedestrian signage across London for the foreseeable future seems to have been justified solely by the results of a survey cited in the Legible London study: In March 2005, 284 pedestrians leaving Leicester Square tube station were asked a number of questions about their tube journey. The key finding seems to be that, “77% referred to relative distance by minutes rather than miles.”
That people exiting a tube station should refer to journeys in terms of minutes rather than miles is hardly surprising. What is surprising though, is that this result seems to have been taken out of context, and used to justify the use of minutes as the standard unit of distance for all new pedestrian signage.
The Legible London study gave no rationale for its apparent lack of consideration of the international norm of using metres for pedestrian signage. Nor, did it cite any other country where minutes were the standard unit of distance on pedestrian signs.
Legible London’s minute-based signage system is not an official national standard, but since its inception, it has been duplicated in several locations outside London.
In May 2020, social distancing was introduced as one of the measures to reduce the transmission of the SARS-CoV-2 virus during the COVID-19 pandemic.
The Units of Measurement Regulations require that standard metric units are used for all measurements regarding health and public safety. Recommendations were made for people to keep 2 metres apart in public spaces. Signs reminding people to keep this distance apart became a common sight in stores.
The Department for Transport also issued diagrams for various temporary road signs to be used during the initial period of the pandemic. These included signs for pedestrians on public footpaths.
The use of metric units for these signs attracted no particular attention, as distances in metres are well understood. It is only noteworthy because the DfT tend to use yards for distances on conventional road signs for pedestrians, and in this instance, where the signs were clearly regarding public health, they quite rightly kept to the original metric units.
Social distancing signs – 2020
When road signs finally go metric, any politician that needs to approve the change, but is fearful that there might be public resistance to a switch from yards to metres, should be reassured by the fact there was no hint of any such reaction to the use of metres while social distancing measures were in force.
A fire in a tunnel can lead to a rapid accumulation of smoke, which can severely restrict visibility and breathing. Emergency exit signs, placed at regular intervals, help pedestrians find the nearest safe exit.
The Vienna Convention on Road Signs and Signals of 1968, of which the UK is a signatory nation, specifies standard diagrams for emergency exit signs, with distances in metres. There is no prescribed option to use yards instead of metres:
|The signs G, 24a, G, 24b and G, 24c are examples of signs to indicate the direction and distance of the nearest emergency exits. In tunnels, they shall be placed at a maximum distance of 50 m apart and at a height of 1 to 1.5 m on the sidewalls.|
Part I: Convention on Road Signs and Signals – Annex 1
UK legislation, in common with legislation throughout most of Europe, specifies a maximum spacing between signs of 25 metres, rather than the original 50 metres.
Emergency exit signs in road tunnels are clearly a matter of public safety, and should therefore be required to show distances in metres as per the Units of Measurement Regulations. However, these signs fall within the scope of road traffic signs. In most countries this distinction would be irrelevant, but in the UK, the Department for Transport still retains the use of imperial units for distances on regular road signs.
Unfortunately, the DfT has opted to treat emergency exit signs for pedestrians as regular road signs, rather than as an issue of public safety. As such, it has opted to require that they show distances in imperial units.
TSRGD Diagram 2711.1
The Traffic Signs Regulations and General Directions (TSRGD) stipulates that the distances shown on emergency exit signs should be in one of two formats:
- yards, or
- miles (rounded to the nearest ¼ mile)
No advice is given about the rounding of values in yards.
Oddly, the format dictated for each sign depends on the total distance between the two nearest exits, and not on the size of the individual distances shown.
|CURRENT SIGNS||METRIC SIGNS|
|Distance from exit||(exits up to 880 yards apart)||(exits > 880 yards apart)|
|300 m||328 yards||¼ mile||300 m|
|350 m||383 yards||¼ mile||350 m|
|400 m||437 yards||¼ mile||400 m|
|450 m||492 yards||¼ mile||450 m|
|500 m||547 yards||¼ mile||500 m|
|550 m||601 yards||¼ mile||550 m|
|600 m||656 yards||¼ mile||600 m|
|650 m||711 yards||½ mile||650 m|
|700 m||766 yards||½ mile||700 m|
|750 m||820 yards||½ mile||750 m|
|800 m||875 yards||½ mile||800 m|
|850 m||930 yards||½ mile||850 m|
|900 m||984 yards||½ mile||900 m|
|950 m||1039 yards||½ mile||950 m|
|1000 m||1094 yards||½ mile||1000 m|
|1050 m||1148 yards||¾ mile||1050 m|
When distances are required to be in miles and fractions, the step size is ¼ mile, which corresponds to about 400 metres. This is clearly inappropriately coarse for pedestrian signs that are placed every 25 metres, and results in the value shown only changing after every 16 signs.
Why metric signs are clearer than imperial signs
The following two examples illustrate how the different imperial formats are applied:
- 350 metres into an 800-metre tunnel, the two distances would be shown as 383 yards and 492 yards.
- 300 metres into a 900-metre tunnel, both distances would be shown as ¼ mile. This is because 300 metres rounded to the nearest ¼ mile is ¼ mile, and 600 metres rounded to the nearest ¼ mile is also ¼ mile.
|Which is the nearest exit?|
Using metric signs, distances shown can match the positions of the signs, which are in round multiples of 25 metres. Clear, precise information leaves no doubt as to the distance and direction of the nearest exit.
|Nearest exit is on the left|
The TSRGD rules also imply that when the distance between exits is greater than 880 yards (about 805 m), all distances of 200 metres or less should actually be shown as 0 miles. This is because 200 metres rounded to the nearest ¼ mile is 0 miles.
In practice, the TSRGD rules regarding the use of miles tend to be ignored, and all distances, long and short, are shown in yards rounded to the nearest yard.
CD 352 Design of road tunnels, Design Manual for Roads and Bridges
The requirement for distances to be signed in yards, rather than the simpler and more obvious metres, means that distances shown have to be rounded to odd values.
It is also important to note that no other major country uses yards on road signs, and so any visitor from abroad finding themselves in the unfortunate position of seeking an emergency exit from a tunnel fire, will have the additional burden of decyphering the UK’s use of antiquated measurement units while trying to escape.
Switching to the use of metres on emergency exit signs will have the following benefits:
- No rounding of distance values needed,
- Signs will be compliant with UK safety regulations,
- Signs will be compliant with Vienna Convention on Road Signs and Signals,
- Universally understood measurement symbols,
- No one under 60 was taught in yards and miles at school, but everyone is familiar with distances in metres.
Action required by : Government
- Emergency exit signs – Purely in the interests of safety, the TSRGD should be amended without delay to stipulate that all distances on emergency exit signs be in metres, using the standard “m” symbol. This can be carried out ahead of the general road signs metrication programme. The number of signs affected across the whole country will be small compared with other classes of road signs such as height restriction signs.