# Traffic Signs Manual/Chapter 3/2008/14

GENERAL
14.1 Traffic authorities have a duty under section 85 of the Road Traffic Regulation Act 1984 to erect and maintain prescribed speed limit signs on their roads in accordance with the Secretary of State's directions; i.e. the signs must be prescribed by and provided in accordance with the Traffic Signs Regulations and General Directions 2002 unless they have been specially authorised. Signs that do not strictly follow the Regulations and the Directions (see para 1.4 in respect of Northern Ireland), or have not been specially authorised are not lawfully placed and the speed limit might be unenforceable. To avoid the risk of failed prosecutions, it is of the greatest importance that speed limits be signed lawfully. It is equally important that speed limits be signed clearly and in accordance with this guidance, so that at no time will drivers be in any doubt about the prevailing limit.
14.2 Speed limits are defined in regulation 5 and are referred to in this section as follows:
(i) National speed limit, being 70 mph on motorways and dual carriageway roads and 60 mph on single carriageway roads (see regulation 5(2))
(ii) Maximum speed limit, being an upper limit (see regulation 5(1)). This includes restricted roads (sections 81 and 82 of the Road Traffic Regulation Act 1984), which are those roads with a speed limit of 30 mph by virtue of the presence of a system of street lighting (carriageway lighting in Scotland) where lamps are placed not more than 183 metres apart (185 metres in Scotland)
(iii) Minimum speed limit, being a speed below which vehicles must not be driven (see regulation 5(1)).
Any maximum speed limit below 30 mph (other than a temporary limit made under section 14 of the Road Traffic Regulation Act 1984, or a 20 mph limit or a 20 mph zone) requires the consent of the Secretary of State (paragraphs 13 and 14 of Schedule 9 to the Act as amended by the Road Traffic Regulation Act (Amendment) Order 1999); such limits are unlikely to be agreed. References in this section to street lighting should be taken in Scotland to be references to carriageway lighting.
14.3 The Directions set out the requirements for the placing of signs to indicate speed limits. These are described in detail in the following paragraphs (see para 1.4 in respect of Northern Ireland). In most cases these are minimum requirements; additional signs may be provided where appropriate. This section supersedes Traffic Advisory Leaflet 1/95, which is now withdrawn.
TERMINAL SIGNS INDICATING MAXIMUM AND NATIONAL SPEED LIMITS
670 Maximum speed limit in miles per hour
The numerals may be varied (see para 14.4)
671 National speed limits apply
14.4 Terminal signs to diagram 670, provided in accordance with directions 8 and 9, are used to indicate the beginning of maximum speed limits. These signs will indicate a speed of 20 mph (except for a 20 mph zone; see paras 14.30 to 14.32), 30 mph, 40 mph or 50 mph. On dual carriageway roads only, they may indicate a speed of 60 mph. Diagram 670 is not used to indicate the national speed limit; the appropriate sign is that shown in diagram 671. All speed limits, except those for tramcars (see para 14.49) are signed in miles per hour.
Figure 14-1 Terminal signs for single carriageway road
Figure 14-2 Terminal signs for dual carriageway road
On wide central reservations the two signs should be mounted separately, closer to each carriageway
| Correct (in accordance with direction 8) | Not lawful (road has only one carriageway for the purposes of direction 8). This arrangement must not be used | Optional (signs may be placed on island as well as on each side of road, but is visually intrusive and not generally recommended) |
Figure 14-3 Terminal signs for single carriageway road with traffic island
14.6 Direction 8(2) introduces the expression "relevant road", which, in the case of speed limits, means the length of road subject to the speed limit that is being signed and to which the speed limit order applies. This term is also used in direction 9 which sets out the requirements for signing speed limits at road junctions.
14.7 Direction 8(3) requires a speed limit terminal sign to be placed on each side of the relevant road, or on each side of the appropriate carriageway if the relevant road is a dual carriageway (i.e. on the near side and on the central reservation), at or as near as practicable to the point where the speed limit begins. On a road with a 30 mph speed limit by virtue of street lighting (i.e. a restricted road; see para 14.2), where the adjacent length of road is unlit and is subject to the national speed limit, the 30 mph speed limit will begin at the first lighting column. The terminal signs are placed on, or in line with, that column as appropriate. To ensure that drivers are aware of the commencement of the 30 mph limit, it is essential that the terminal signs are correctly placed and clearly visible (see para 14.19). If the 30 mph limit is to start at some other point (before or after the street lighting begins), it will be necessary to make a speed limit order and locate the terminal signs accordingly. Where a 30 mph limit commences on an unlit section of road and continues as a restricted road on the lit section, additional terminal signs must not be placed, in either direction, at the point where the street lighting begins, i.e. where the 30 mph speed limit order ends and the restricted road begins (but see para 14.22). Where a single carriageway road has a central traffic island, it is not a dual carriageway at that point (see regulation 4 for definitions of "dual carriageway road" and "central reservation"). The terminal signs should therefore be erected on both sides of the road, not on the near side and the central island. However, a third sign may be erected on the island if the road geometry makes the off side sign difficult to see. A third sign is otherwise unnecessary. Figures 14-1 to 14-3 show the requirements for siting terminal signs on both single and dual carriageway roads.
14.8 Direction 8(4) sets out conditions when a single terminal sign may be used to indicate the beginning of a restriction or prohibition (see para 1.19) but this does not apply to speed limits.
14.9 Direction 9 sets out the circumstances where the requirements specified in direction 8(3) (see para 14.7) may be relaxed. Direction 9(1)(a) removes the requirement to provide terminal signs imposed by direction 8(3) where the relevant road begins and has no junction with another road. This refers to the end of a cul—de—sac, where the speed limit on that road obviously begins but where terminal signs would serve no purpose. Direction 9(1)(b) removes the need to provide terminal signs where the relevant road begins at the junction of another road and both roads are subject to the same speed limit. The main body of direction 9 (i.e. 9(2) to 9(5) inclusive) applies to the signing of road junctions where the relevant road has a junction with the side of another road (referred to as "the other road") and each road has a different speed limit. The relevant road is the side road and the other road is the major road. The signing requirements are set out in paras 14.10 to 14.17. They apply to junctions with all roads to which the public has access, whether private or not (see para 2.1).
14.10 Direction 9(3) is concerned with the sign that indicates the speed limit on the side road (the relevant road) to traffic entering that road from the major road (the other road). A terminal sign need be provided only on the left hand side of the carriageway of the relevant road (the left hand side of the appropriate carriageway in the case of a dual carriageway road) not more than 20m from the junction (see also para 14.13). This distance should be measured from the edge of the carriageway of the major road.
14.11 Direction 9(4) is concerned with the signs that indicate the speed limit in force on the major road (the other road) to traffic leaving the side road (the relevant road). A terminal sign must be provided on each side of the carriageway of the relevant road not more than 20m before the junction unless direction 9(5) applies (see paras 14.12 and 14.13). Where the relevant road is a dual carriageway, this means on each side of the carriageway approaching the junction (i.e. the near side and the central reservation). If the relevant road is not a dual carriageway, but has a central traffic island within 20m of the junction, the terminal signs must be erected on both sides of the road, not just on the ​near side and on the central island. A third sign should be erected on the island only if the road geometry makes the off side sign difficult to see. The distance of 20m should be measured from the edge of the carriageway of the major road. Where the major road (the other road) is subject to the national speed limit, directions 10(7) and 10(8) apply (see para 14.16).
14.12 Direction 9(5) applies where the speed limit on the major road (the other road) is higher than the speed limit on the side road (the relevant road). In this case, the terminal signs referred to in para 14.11 are not required where a repeater sign has been placed on the major road on each side of, and not more than 100m from, the junction. This relaxation does not apply where the major road is Direction 9(3) requires only one sign on entering the side road. Direction 9(4) requires two signs to indicate the speed limit on the major road (the other road) when leaving the side road. Direction 9(5) does not apply as the speed limit is lower on the major road subject to the national limit (see para 14.16). Where the junction configuration or permitted turning movements are such that it is not practicable to provide repeater signs on the major road in accordance with direction 9(5), a pair of terminal signs must be provided on the exit from the side road in accordance with direction 9(4) (see para 14.11).
Figure 14-4 Terminal signs at a road junction where the side road (relevant road) has a higher speed limit than the major road
Figure 14-5 Terminal signs at a road junction where the side road (relevant road) has a lower speed limit than the major road
14.13 Figures 14-4 to 14-7 illustrate the signing requirements imposed by directions 9(2) to 9(5). It should be stressed that these are the minimum requirements that have to be met in order to comply with the Regulations and Directions and with section 85 of the Road Traffic Regulation 1984. There is nothing to prevent traffic authorities from providing additional terminal signs at road junctions, Direction 9(3) requires only one sign on entering the side road. Direction 9(5) allows the two signs indicating the speed limit on the major road when leaving the side road (as shown in figure 14-4) to be omitted where the higher speed limit is indicated by repeater signs not more than 700m from the junction ​e.g. a sign on each side of the carriageway of the side road in both directions (see figure 14-8). For example, it might be better to inform drivers in the side road of a higher limit on the major road by providing terminal signs rather than depending solely on repeater signs on the major road. This might be a consideration where the speed limit increases from, say, 30 mph to 50 mph and drivers need to be aware of much faster traffic speeds when assessing gaps in the traffic flow in order to join the major road. It might also arise if placing repeater signs within 100 m of the junction would conflict with terminal signs for a change in the limit on the major road (see para 14.24). Where the side road makes an acute angle with the major road, it might be better to provide two signs on the entry to the side road, particularly where the speed limit is higher, to avoid drivers being misled into thinking that the sign applies to the major road (see figure 14-9). There may be some junction layouts where it is not practicable to provide terminal signs within 20m of the junction. In such a situation, the speed limit orders for the side and major roads will need to provide for the speed limit on the major road to extend for a short distance along the side road; terminal signs would then be provided in accordance with direction 8(3).
Figure 14-6 Terminal signs at a road junction where the side road (relevant road) has a lower speed limit than the major road
Direction 9(3) requires only one sign on entering the side road. Direction 9(5) does not apply, as it does for figure 14-5, because the repeater signs indicating the higher speed limit are more than 100m from the junction (note: if only one of the two repeaters shown was more than 100m from the junction, direction 9(5) would still not apply). Direction 9(4) therefore applies and requires two terminal signs on the exit from the side road
Figure 14-7 Terminal signs at a road junction where the side road (relevant road) has a lower speed limit than the major road
Direction 9(3) requires only one sign on entering the side road. Direction 9(5) does not apply, as it does for figure 14.5|14-5, because there are no repeater signs indicating the higher speed limit (note: this applies where the higher limit is 30 mph and the road has street lighting—see para 14.21). Direction 9(4) therefore applies and requires two terminal signs on the exit from the side road
Figure 14-8 Full provision of terminal signs at a road junction where the side road (relevant road) has a lower speed limit than the major road
Although this exceeds the requirements of direction 9 as shown in figures 14-5 and 14-6, it is permitted and is likely to better inform drivers at many locations
Figure 14-9 Road junction where the side road makes an acute angle with the major road (Signs for drivers entering the side road)
Although direction 9(3) requires only one sign to indicate the speed limit in the side road (the relevant road), drivers could mistakenly think that the sign applies to the major road (the other road); the additional sign overcomes this problem
14.14 Direction 10 sets out the requirements for signing the end of a speed limit, i.e. the point where a speed limit changes to the national limit. Direction 10(4) requires a terminal sign to diagram 671, indicating that a road ceases to be subject to a speed limit (i.e. the national speed limit applies), to be placed on each side of the relevant road or on each side of the appropriate carriageway if the relevant road is a dual carriageway (i.e. on the near side and on the central reservation) at or as near as practicable to the point where the speed limit ends. In practice, on a single carriageway road these signs would be mounted back to back with the sign to diagram 670. On a dual carriageway road, the sign on the central reservation would be mounted back to back with the sign to diagram 670, unless the reservation is very wide and the two signs need to be mounted separately, closer to each carriageway.
14.15 At a junction where the side road (the relevant road) is subject to the national limit and the major road it joins (the other road) has a different speed limit, directions 10(5) and 10(6) require one terminal sign to diagram 671 to be placed on the left hand side of the relevant road or on the left hand side of the appropriate carriageway of a dual carriageway road not more than 20 m from the major road, facing traffic turning into the side road from the major road (see figure 14-10). This is identical to the requirement for other speed limit signs as described in para 14.10.
Figure 14-10 Terminal signs at a road junction where the side road (relevant road) is subject to the national speed limit
Directions 7 0(5) and 7 0(6) require only one sign to diagram 67 7 on entering the side road. Direction 9(4) requires two signs to indicate the speed limit on the major road (the other road) when leaving the side road. Direction 9(5) does not apply as the speed limit is lower on the major road
Figure 14-11 Terminal signs at a road junction where the major road (other road) has no street lighting and is subject to the national speed limit
Direction 9(3) requires only one sign on entering the side road. Directions 70(7) and 70(8) require two signs to diagram 677 to indicate the national speed limit on the major road when leaving the side road
14.16 At a junction where the major road (the other road) is subject to the national speed limit and the side road (the relevant road) has a different speed limit, directions 10(7) and 10(8) require signs to diagram 671 to be placed on each side of the relevant road or on each side of the appropriate carriageway if the relevant road is a dual carriageway (i.e. on the near side and on the central reservation) not more than 20m from the major road, facing traffic approaching the major road (see figures 14-11 and 14-12). Where the side road is not a dual carriageway, but has a central traffic island within 20 m of the junction, the terminal signs must be erected on both sides of the road, not just on the near side and on the central island. A third sign should be erected on the island only if the road geometry makes the off side sign difficult to see. The distance of 20m should be measured from the edge line of the major road. This is identical to the requirement for other speed limit signs as described in para 14.11. However, unlike the situation where the major road is subject to a speed limit (other than the national limit) higher than that on the side road (see para 14.12), the terminal signs to diagram 671 are not omitted when the major road has a system of street lighting with repeater signs to diagram 671 within 100 m of the junction. If terminal signs were not used, drivers leaving the side road would not be prepared for the much higher speed of traffic on the major road.
Figure 14-12 Terminal signs at a road junction where the major road (other road) has a system of street lighting and is subject to the national speed limit
Direction 9(3) requires only one sign on entering the side road. Directions 70(7) and 70(8) require two signs to diagram 677 to indicate the national speed limit on the major road when leaving the side road (whether or not there are repeater signs on the major road within 100m of the junction)
14.17 It should be stressed that figures 14-10 to 14-12 illustrate the minimum signing requirements imposed by directions 9 and 10. These have to be met in order to comply with the Regulations and Directions and with section 85 of the {{short-title/y|s=Road Traffic Regulation|y=1984. There is nothing to prevent traffic authorities from providing additional terminal signs at junctions if this helps to make the signing easier to see, or its meaning clearer, e.g. where the side road makes an acute angle with the major road. It might be better to provide two signs to diagram 671 on the entry to the side road so that drivers are not misled into thinking that the national speed limit sign applies to the major road (see figure 14-13).
Figure 14-13 Road junction where the side road makes an acute angle with the major road (Signs for drivers entering the side road)
Although directions 70(5) and 70(6) require only one sign to indicate the speed limit in the side road (the relevant road), drivers could mistakenly think that the sign applies to the major road (the other road); the additional sign overcomes this problem
14.18 The placing of terminal signs at junctions as specified in directions 9 and 10 (see paras 14.10 to 14.17) applies generally to simple priority junctions, including crossroads. For other types of junction, such as roundabouts and those controlled by signals, drivers are likely to require more guidance on the speed limits in force; it is strongly recommended that full signing is provided as shown in figures 14-14 to 14-16. This would also aid enforcement where it might be difficult to establish which is the relevant road and which is the other road at the junction.
Figure 14-14 Example of a roundabout junction (see para 14.18)
Figure 14-15 Example of a signalled junction (see para 14.18)
Figure 14-16 Example of a signalled junction with three different speed limits (see para 14.18)
Table 14-1 Sizes of terminal signs (other than at junctions) :
| Type of approach road | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) |
| Type of approach road | 30 | 40 | 50 | 60 | 70 |
| Size of sign (mm) |||||
| Single carriageway or one-way road | 600 | 600 | 600 | 750 (600) | – |
| Wide single carriageway (10 m or more) | – | 600 | 750 | 900 (750) | – |
| Dual carriageway | – | 750 (600) | 900 (750) | 900 | 1200 (900) |
| Motorway | – | – | 1200 | 1200 | 1200 |
NOTE 1: The smaller alternative sizes shown in brackets may be used where the 85th percentile speed on the approach road is at least 10 mph less than the legal speed limit on that road or where a narrow central reservation or similar constraint makes the larger size impracticable.
NOTE 2: Where the terminal sign indicates a higher speed limit, this should generally be the 600 mm size, except that a 750 mm sign should be used on dual carriageway roads where the lower approach speed limit is 50 or 60mph.
NOTE 3: Where signs of different diameters are to be mounted back to back (and a backing board is not used), consideration should be given to using the larger diameter for both, as this should result in a neater and less cluttered assembly.
NOTE 4: See table 14-2 (Note 3) for use of the prescribed size of 450 mm as a terminal sign. The prescribed 300 mm sign is used only for repeater signs (see table 14-4) and never as a terminal sign. The prescribed 1500 mm sign is for use only at road works (see Chapter 8, Part1). ​14.19 The size of the terminal sign to diagram 670 or 671, as shown in tables 14-1 and 14-2, depends upon the approach speed limit, not the limit being signed. Unless it is impracticable to do so (see Notes to the tables), the standard size of sign should be used on each side of the carriageway. This also produces a more balanced appearance. The signs should be sited so that they can be seen in good time to allow drivers to adjust their speed by the time they pass them. Obstructions to visibility such as vegetation, street furniture, buildings, bends, humps, other topographical features etc., need to be taken into account when determining the terminal point for a speed limit order. "Countdown" signs giving advance indication of a change in the speed limit are not prescribed and must not be used. Nor should the sign to diagram 818.2 be used to indicate a speed limit ahead. Any development that takes place after a speed limit order has been made might require re-siting of the terminal signs to maintain adequate visibility, and amendment of the order. Table 14-3 shows the minimum clear visibility distances that should be maintained for terminal signs. These are based on speed differential rather than simply the approach speed limit and should normally be measured from the centre of the most disadvantaged driving lane. It is important that the full recommended sight line to the whole of the sign face is preserved.
14.20 Guidance on the illumination of speed limit terminal signs can be found in paras 14.54 to 14.58, and on their mounting and co-location with other signs in paras 14.60 and 14.62.
Table 14-2 Sizes of terminal signs at junctions :
| Type of junction and location of sign | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) | Speed limit on approach road (mph) (higher limit) |
| Type of junction and location of sign | 30 | 40 | 50 | 60 | 70 |
| Size of sign (mm) |||||
| Signal-controlled junction (signs viewed only from turning vehicles) | 600 | 600 | 600 | 600 (750) | 600 (750) |
| Signal-controlled junction (other signs) | 600 | 600 | 750 | 750 | 900 |
| Side road approach to a priority junction | 600 | 600 | 600 | 600 | 750 |
| Entry into side road at a priority junction | 600 | 600 | 600 | 600 (750) | 600 (750) |
| Approach to a roundabout | 600 | 600 | 600 | 750 (600) | 900 |
| Exit from a roundabout | 600 | 600 | 600 | 600 (750) | 600 (750) |
| NOTE 1: The larger alternative sizes shown in brackets might be appropriate where there are high-speed flow conditions such as a diverge lane at a priority junction or spiral markings on a large roundabout. The smaller alternative size of 600 mm shown in brackets for the approach to a roundabout may be used where the 85th percentile speed is less than 50 mph. ||||||
| NOTE 2: Where the terminal sign indicates a higher speed limit, this should generally be the 600 mm size. ||||||
| NOTE 3: Where the width of the verge is insufficient to allow the provision of a 600 mm sign shown in the table or referred to in Note 2, a 450 mm sign might have to be used. ||||||
| NOTE 4: Where signs of different diameters are to be mounted back to back (and a backing board is not used), consideration should be given to using the larger diameter for both, as this should result in a neater and less cluttered assembly. ||||||
| NOTE 5: The prescribed size of 300 mm is used only for repeater signs (see table 14-4) and never as a terminal sign. The prescribed 1500 mm sign is for use only at road works (see Chapter 8, Part 1). ||||||
Table 14-3 Minimum clear visibility distances for terminal signs (other than entering a side road) :
| Approach road speed limit for private cars (mph) | Speed limit sign (mph) | Speed limit sign (mph) | Speed limit sign (mph) | Speed limit sign (mph) | Speed limit sign (mph) |
| Approach road speed limit for private cars (mph) | 20 | 30 | 40 | 50 | 60 |
| Visibility distance of sign (m) |||||
| 70 | – | 165 | 140 | 110 | 75 |
| 60 | – | 115 | 95 | 65 | – |
| 50 | – | 75 | 50 | – | – |
| 40 | – | 40 | – | – | – |
| 30 | 30 | – | – | – | – |
| NOTE 1: On the side road approach to a priority junction or on any road where the speed limit increases, the visibility distance for each approach speed should be not less than the lowest value shown for that speed (e.g. 50 m for an approach speed limit of 50 mph). Where the approach speed limit is 20 mph, the minimum visibility distance is 20 m. NOTE 2: Where the 85th percentile speed on the approach road is at least 10 mph less than the legal speed limit on that road, the clear visibility distance may be reduced to that appropriate to the actual speed (e.g. on a country lane subject to the national limit, where the 85th percentile speed is 50 mph the clear visibility distance should not be less than 75 m when approaching a 30 mph speed limit, and not less than 50 m when approaching a 40 mph or 50 mph speed limit). NOTE 3: The minimum clear visibility distance indicated should be provided for both terminal signs. ||||||
REPEATER SIGNS INDICATING MAXIMUM AND NATIONAL SPEED LIMITS
14.21 Where a speed limit other than the national limit is in force, direction 11(2) requires that repeater signs are provided at regular intervals along the road. However, this does not apply to a 30 mph speed limit on a road with a system of carriageway lighting; in built—up areas it would be impracticable to place 30 mph repeater signs on every road. To do so in some cases but not others would result in inconsistency and driver uncertainty. This is therefore prohibited by direction 11(4). Section 82 of the Road Traffic Regulation Act 1984 defines a road that has a system of street lighting (carriageway lighting in Scotland) as being a "restricted road" (see para 14.2). Section 81 specifies that the speed limit along such a road shall always be 30 mph unless an order has been made to impose another limit and remove the restricted road status. The presence of carriageway lighting therefore means that a road automatically has a speed limit of 30 mph with the lamps taking the place of repeater signs. It is therefore of critical importance that, when lit roads have a speed limit other than 30 mph, repeater signs are always provided at the appropriate intervals. Failure to do so undermines confidence in the signing of all speed limits, as drivers have only the repeaters to tell them that the limit is not 30 mph. Where a speed limit, other than 30 mph, applies before and after the point where the street lighting begins, a repeater sign should be located on, or in line with, the first lighting column.
14.22 Where a 30 mph speed limit is imposed on a road without street lighting, it is necessary to make an order. In this case 30 mph repeater signs must be provided (direction 11(2)). Where a road subject to 30 mph limit has street lighting for only part of its length, it is recommended that the first repeater sign for the unlit section when leaving the lit section should be placed at a distance of not more than 100 m from the last street lamp. Where two consecutive street lamps within a system of street lighting are more than 183 m apart (185 m in Scotland) repeater signs should be provided on the section of road between the two lamps. That part of the road must also be covered by a speed limit order as it is not a "restricted road" (see para 14.21).
14.23 A road subject to the national speed limit (see para 14.2) does not require repeater signs except when it has a system of street lighting (direction 11(5)). The purpose of the signs is to remind drivers that the road is not a restricted road with a speed limit of 30 mph. At the point where street lighting commences on a road subject to the national speed limit, the first repeater sign should be placed in line with the first lamp; in most cases the sign would be mounted on the lighting column. This sign should be the appropriate size for a repeater sign (see table 14-4) and not the larger terminal sign. Repeater signs indicating the national speed limit are to diagram 671 and not diagram 670. National speed limit repeater signs are not required on motorways with street lighting (see para 14.27).
​14.24 Sizes, maximum recommended spacing and minimum visibility distances for repeater signs are shown in table 14-4. Repeater signs should be staggered on alternate sides of a single carriageway road, or on alternate sides of each carriageway of a dual carriageway road, in accordance with table 14-4. Guidance on the mounting of repeater signs, and co—location with other signs, can be found in paras 14.61 and 14.62. At a junction where the major road has a higher speed limit than the side road, it will be necessary to reduce the spacing of the repeater signs on the major road where these are used to indicate the speed limit to drivers entering from the side road, as the signs must be no more than 100 m from the junction in both directions (see para 14.12). Where this would result in a repeater sign being close to a terminal speed limit sign on the major road, it might be better to omit the repeater and use two terminal signs for traffic leaving the side road (see paras 14.12 and 14.13).
Table 14-4 Size, spacing and minimum clear visibility distances (CVD) for repeater signs :
| Speed limit and type of road (Notes 1 and 2) | Size of sign (mm) | Maximum distance (m) between | Maximum distance (m) between | Maximum distance (m) between | CVD(m) |
| Speed limit and type of road (Notes 1 and 2) | Size of sign (mm) | Consecutive signs on alternate sides of the carriageway (Note 3) | Consecutive signs on the same side of the carriageway | Terminal sign and first repeater | CVD(m) |
| 20 mph zone | – | No repeaters | No repeaters | No repeaters | – |
| 20 mph | 300 | 200 | 300 | 200 | 20 |
| 30 mph with street lighting | – | No repeaters | No repeaters | No repeaters | – |
| 30 mph without street lighting | 300 | 250 | 400 | 200 | 30 |
| 40 mph | 300 | 350 | 500 | 250 | 40 |
| 50 mph | 450 | 450 | 700 | 350 | 50 |
| 60 mph (dual carriageway) | 600 | 500 | 800 | 400 | 60 |
| National speed limit (lit single carriageway) | 450 | 500 | 800 | 400 | 60 |
| National speed limit (lit dual carriageway) | 600 | 600 | 900 | 450 | 70 |
| National speed limit (unlit road) | – | No repeaters | No repeaters | No repeaters | – |
| NOTE 1: For the purposes of direction 11, street lighting or lit carriageway means "a system of carriageway lighting furnished by lamps lit by electricity placed not more than 183 metres apart in England and Wales or not more than 185 metres apart in Scotland". Where a road does not have a system of street lighting throughout and requires repeater signs for both the lit and unlit sections, a repeater sign should be provided at the point where the street lighting commences. NOTE 2: Sign size, spacing and clear visibility distance for motorways, including link roads, will be the same as shown for 40 mph, 50 mph and 60 mph, as appropriate. Repeater signs are not used on motorways to indicate the national speed limit, whether or not there is street lighting. NOTE 3: Repeater signs need not be provided where the length of the speed limit is less than the distance shown in this column. ||||||
Figure 14-17 Terminal signs at a road junction where the major road (other road) is a dual carriageway with a speed limit of 60mph and the side road is a single carriageway subject to the national speed limit of 60 mph
Although the actual speed limit is the same on both roads (i.e. 60 mph), two terminal signs to diagram 670 should be placed facing traffic leaving the side road. This is to ensure that drivers, when turning into the dual carriageway road, do not assume that the national speed limit of 70 mph applies. The repeater signs alone would not be sufficient for this purpose. Directions 7 0(5) and 7 0(6) require only one sign to diagram 677 on entering the side road
ALL-PURPOSE DUAL CARRIAGEWAY ROADS WITH A SPEED LIMIT OF 60 MPH
14.25 Where a road is part dual carriageway and part single carriageway and has a speed limit of 60 mph throughout, terminal signs must be provided at the point where the central reservation begins or ends. The speed limit on the dual carriageway will be signed as a 60 mph speed limit with terminal and repeater signs to diagram 670, varied to show "60". An order will be required to impose a 60 mph limit on the dual carriageway section. The single carriageway road will be subject to the national speed limit and should be signed as such with signs to diagram 671. Repeater signs on the single carriageway should be provided only if there is a system of street lighting (see para 14.23).
14.26 Where a two—way single carriageway road subject to the national speed limit of 60 mph has a junction with a dual carriageway road on which is imposed a speed limit of 60 mph, terminal signs to diagram 670, facing traffic approaching the dual carriageway, should be provided on each side of the road as shown in figure 14-17. In the opposite direction, only one sign, to diagram 671, is required (see directions 10(5) and 10(6)). If the side road forms a short link to another road at a grade separated junction and this other road has a speed limit other than the national limit, it might be preferable to apply this limit to the link road also, to eliminate the short length of national speed limit and hence the number of signs (see figure 14-18). This would not be appropriate, however, where the speed limit on the link road would be unrealistically low for the prevailing conditions.
Figure 14-18 Speed limit on two—way link road between a dual carriageway road with a speed limit of 60mph and a side road with a speed limit of 40 mph (see para 14.26)
MOTORWAYS
14.27 The placing of speed limit terminal and repeater signs is generally the same as for other roads. However, motorways do not have repeater signs indicating the national speed limit where there is a system of street lighting. Most speed limit signs on motorways will be at junctions with all—purpose roads although some lengths of motorway, particularly link roads or slip roads, will have speed limits other than the national limit. In such cases, terminal and repeater signs must be provided in accordance with tables 14-1 to 14-4. Where the start of a motorway (main carriageway or entry slip road) and the adjoining all—purpose road both have the same speed limit, other than the national limit, a repeater sign to diagram 670 should be co—located with the sign to diagram 2901 that indicates the start of the motorway. This ensures that drivers are aware that the national motorway speed limit of 70 mph does not apply at this point (see para 14.28). Where the speed limit on a motorway ends and becomes the national limit, terminal signs to diagram 671 must be erected.
14.28 Where a motorway subject to the national speed limit has a junction with an all—purpose road that has a different limit, terminal signs to diagram 670 must be provided on the exit slip road to indicate the speed limit on the all—purpose road. The requirement under section 85 of the Road Traffic Regulation Act 1984 to provide prescribed speed limit signs (see para 14.1) does not apply to motorways subject to the national speed limit. Signs to diagram 671 are not needed, therefore, on the entry slip road. The sign to diagram 2901, indicating the start of motorway regulations, also indicates that the national speed limit applies. There will be situations where the all—purpose road and the motorway are both subject to the national speed limit, and the all—purpose road or both roads have a system of street lighting. A repeater sign to diagram 671, to be viewed by drivers leaving the motorway, should then be placed on the first lighting column beyond the point where the motorway regulations end (indicated by the sign to diagram 2931). If the all—purpose road is subject to the national speed limit and is unlit, no signs are required. The signing ​principles in this paragraph apply also where the main carriageway of a motorway terminates at a roundabout.
14.29 Where a motorway terminates at a grade separated junction and the main carriageway becomes an all—purpose road, the motorway regulations usually continue through the junction to the point where the entry slip road joins. If the all—purpose road has a lower speed limit than the motorway, this will be signed as described in para 14.28. However, this speed limit might sometimes commence some distance before the slip road joins and the motorway regulations end. A short section of the motorway will then be subject to a speed limit other than the national limit. This must be indicated by terminal and repeater signs. No additional signs are required where the motorway adjoins the all—purpose road; the repeater signs will continue at the appropriate spacing. In the opposite direction, terminal signs to diagram 671 must be provided on the motorway where the national limit commences. A repeater sign indicating the lower limit should be placed at the point where the motorway starts (see para 14.27). The size and spacing of repeater signs are the same on motorways and all—purpose dual carriageway roads subject to the same speed limit (see table 14-4).
20 MPH ZONES
14.30 A 20 mph speed limit is indicated by terminal and repeater signs to diagram 670 in exactly the same manner as any other speed limit (other than a 30 mph limit on a lit road where repeater signs are not permitted) as described in paras 14.4 to 14.24. However, a 20 mph zone, indicated by the sign shown in diagram 674, may be introduced without needing repeater signs (direction 11(3)), but only if it complies with direction 16. This specifies that the sign to diagram 674 may be used only if no part of a road (not being a cul—de—sac less than 80 metres long) within the zone is more than 50 metres (measured along the road) from a traffic calming feature, where a traffic calming feature is defined as:
(a) a road hump constructed pursuant to section 90A of the Highways Act 1980 ("the 1980 Act") or section 36 of the Roads (Scotland) Act 1984 ("the 1984 Act") and in accordance with the Highways (Road Humps) Regulations 1999 or the Road Humps (Scotland) Regulations 1998;
(b) traffic calming works constructed in accordance with section 90G of the 1980 Act or section 39A of the 1984 Act and in accordance with the Highways (Traffic Calming) Regulations 1999 or the Roads (Traffic Calming) (Scotland) Regulations 1994;
(c) a refuge for pedestrians which was constructed pursuant to section 68 of the 1980 Act or section 27(c) of the 1984 Act after 15th June 1999 and is so constructed as to encourage a reduction in the speed of traffic using the carriageway;
(d) a variation of the relative widths of the carriageway or of any footway pursuant to section 75 of the 1980 Act or section 1(1) or 2(1) of the 1984 Act which—
(i) was carried out after 15th June 1999 for the purpose of encouraging a reduction in the speed of traffic using the carriageway; and
(ii) had the effect of reducing the width of the carriageway; or
(e) a horizontal bend in the carriageway through which all vehicular traffic has to change direction by no less than 70 degrees within a distance of 32 metres as measured at the inner kerb radius.
The traffic calming features ensure that the speed limit is self—enforcing and hence repeater signs are not necessary, although direction 11(3) does not prohibit their use. Speed limit zones with such features are generally more effective than 20 mph limits relying on signs alone.
674 Entrance to a 20 mph speed limit zone
The place name may be omitted or varied to a road safety slogan (advertising material or political slogans must not be used). The symbol or pictogram may be varied or omitted. The place name may be in any style of lettering. Any contrasting colours except red may be used for the place name and the background of that part of the sign. The lower panel may be omitted
675 End of a 20 mph speed limit zone
The 30mph speed limit may be varied to another speed limit. The upper panel may be replaced by a roundel in the form of diagram 677 against a grey background to indicate that a national speed limit applies
also applies where a road outside the zone has a junction with the side of a road that is within the zone (i.e. the major road at the junction is within the zone and the side road is outside the zone). Only one size of sign is prescribed, although the lower panel may be varied or omitted. The speed limit roundel must not be varied to any other speed limit. }} 14.32 The end of the zone is indicated by the sign to diagram 675, with the upper panel showing the adjacent speed limit. Where this is the national speed limit, the roundel is varied to diagram 671 on a grey background as detailed on working drawing P 675 (see para 1.9). Two signs to diagram 675 should be provided, one on each side of the carriageway, unless they are placed at a junction. Reduced signing might then be possible (see paras 14.10, 14.12 and 14.15). Where the adjacent speed limit is 20 mph (without traffic calming features), the signs to diagram 675 are replaced by 20 mph terminal signs to diagram 670.
EXTENDING THE LENGTH OF AN EXISTING 30 MPH SPEED LIMIT
7032 Temporary sign indicating the start of a newly imposed 30mph speed limit which is contiguous to an existing 30 mph speed limit
Figure 14-19 Use of the temporary sign to diagram 7032 to indicate the extension of a 30 mph speed limit on a road with a system of street lighting
​14.34 Direction 37(2) sets out the conditions, all of which must be met, for the use of the sign to diagram 7032; they are:
(i) The sign must indicate only a 30 mph speed limit (it must not be used to indicate any other speed limit)
(ii) The road must have a system of street or carriageway lighting
(iii) The road must have been subject to a higher speed limit (i.e. a sign to diagram 7032 is not used where the previous speed limit was 20 mph)
(iv) The sign must be located as near as practicable to the point where the original 30 mph limit ended (i.e. where the previous terminal signs have been removed)
(v) The sign must not be used at the point where the new 30mph limit ends and changes to another limit (i.e. the point where new terminal signs are placed)
(vi) The sign must be removed not later than six months after the day on which the new speed limit comes into force.
14.35 The x—height of the sign will depend on the location. In most cases the smallest size of 50 mm should be sufficient. A larger size might be required where the conspicuity of the sign needs to be increased, such as on a dual carriageway road. Only one sign, mounted on the near side, will normally be needed although a second sign on the off side should be provided where a near side sign is liable to be obscured (e.g. on a dual carriageway road).
MINIMUM SPEED LIMITS
672 Minimum speed limit in miles per hour
673 End of a minimum speed limit
The numerals on both signs may be varied
14.36 Minimum speed limit orders are not commonly made, as it can be difficult to determine the minimum speed to be expected from vehicles in free—flow conditions. Where there is a particular problem with slow—moving vehicles, it might be preferable to prohibit certain types of traffic from the road, as described in section 5; this is likely to be easier to enforce. Where a minimum speed limit is introduced, this will be in addition to the maximum or national speed limit in force. There might be scope to co—locate the signs for both limits, especially the repeater signs; minimum speed limit signs should be mounted below the maximum and national speed limit signs.
14.37 The start of a minimum speed limit is indicated by a terminal sign to diagram 672. A smaller size is used as a repeater sign. The end of the limit is indicated by a terminal sign to diagram 673. Directions 8(3) and 10(4) apply to the placing of terminals signs to indicate the start and end of a minimum speed limit respectively, in the same way that they apply to maximum and national speed limits. Terminal signs must be placed on each side of the road or on each side of the appropriate carriageway of a dual carriageway road (i.e. on the near side and on the central reservation) at or as near as practicable to the point where the speed limit begins. However, directions 9, 10(5) and 10(6) do not apply to minimum speed limits and there is no relaxation from the requirements of directions 8(3) and 10(4) when the terminal signs are placed in a side road at a junction. Direction 11(2) requires repeater signs to diagram 672 to be provided at regular intervals along the road.
Table 14-5 Size of minimum speed limit signs :
| Maximum speed limit | Size of sign (mm) | Size of sign (mm) |
| Maximum speed limit | Terminal | Repeater |
| 40mph and below | 600 | 300 |
| 50mph | 600 | 300 |
| 60mph (dual carriageway) | 600 | 450 |
| National limit (single carriageway) | 600 | 450 |
| National limit (dual carriageway) | 900 | 450 |
| NOTE: For terminal signs, the maximum speed limit is that on the approach. |||
Table 14-6 Minimum clear visibility distances in metres for minimum speed limit terminal signs :
| Dual carriageway road subject to the national speed limit | 75 |
| Dual carriageway road subject to a maximum speed limit of 60 mph or a single carriageway road subject to the national speed limit | 65 |
| Any other road | 50 |
| NOTE: The minimum clear visibility distance indicated should be applied to both terminal signs. ||
Table 14-7 Spacing of minimum speed limit repeater signs (metres) :
| Maximum distance between a terminal sign and first repeater | 250 |
| Maximum distance between consecutive signs on the same side of the carriageway | 350 |
| Maximum distance between consecutive signs on alternate sides of the carriageway | 500 |
| NOTE 1: The spacing of repeaters is the same for all minimum speed limits and types of road. NOTE 2: Repeater signs need not be provided where the length of the speed limit is less than 350 m. ||
14.38 The sizes of minimum speed limit terminal and repeater signs are shown in table 14-5, the minimum clear visibility distance in table 14-6 and the spacing of repeater signs in table 14-7.
INFORMATORY SIGNS FOR SPEED CAMERAS
878 Area in which cameras are used to enforce speed limits (alternative types) 1000 max
879 Reminder to drivers within an area in which cameras are used to enforce speed limits
14.39 Where a speed limit is enforced by the use of cameras, traffic authorities should follow the signing, visibility and conspicuity guidance set out in DfT Circular 01/2007 ”Use of speed and red-light cameras for traffic enforcement: guidance on deployment, visibility and signing”. The Department also issued an ”Aide Memoire on Speed Limit and Safety Camera Signing” in July 2006. Any reference in the circular and aide memoire to Traffic Advisory Leaflet 1/95 (now withdrawn) should be taken as a reference to this section.
| Diameter of speed limit roundel equal to 300mm | Diameter of speed limit roundel greater than 300mm |
Figure 14-20 Co-located speed limit sign to diagram 670 and camera reminder sign to diagram 879
The backing board must not have any kind of border. The colour may be varied to grey. The roundel may be varied to diagram 677 (national speed limit)
placed only in an area or along a route where enforcement cameras are from time to time in use. The sign to diagram 879 is a reminder that camera enforcement is taking place, and may be used more frequently than the sign to diagram 878. It is often co—located with a speed limit sign (see para 14.43).
14.41 The size of the sign to diagram 878 is related to the speed of traffic and is specified in Appendix A. The size of the sign to diagram 879 will depend on whether or not it is co—located with a speed limit sign to either diagram 670 or 671. Where it is mounted on its own, the height of the sign should not be less than the size of the speed limit repeater signs as specified in table 14.4|14-4. On lit 30mph roads, the 300 mm size should be used. Where diagram 879 is co—located with diagram 670 or 671, the size of the sign should be as shown in figure 14-20.
14.42 Where camera enforcement utilises two cameras to measure the average speed of a vehicle over a set distance, the sign shown in figure 14-21 may be used. Although based on diagram 878, the sign is not prescribed by the Regulations. It is shown on working drawing NP878.1 (available from the Department) and requires authorisation (see para 2.1). The size of the sign will be the same as specified for diagram 878 in Appendix A.
Figure 14-21 Indication that cameras are used to measure the average speed of a vehicle along a length of road (alternative types)
This sign is not prescribed by the Regulations and requires authorisation
880 Speed camera ahead and reminder of 30 mph speed limit
880.1 Speed camera ahead and reminder of national speed limit on an unlit road
14.44 Where a camera is used to enforce the national speed limit on an unlit road, the sign to diagram 880.1 (introduced by the Traffic Signs (Amendment) Regulations and General Directions 2008) may be used. Direction 32(4) permits up to two signs to be placed on any approach to an enforcement camera. The sign to diagram 880.1 must not be used where there is a system of carriageway lighting (direction 32(3)): repeater signs to diagram 671 should be used, co-located with diagram 879 as appropriate (see figure 14-20).
14.45 Only one size of sign is prescribed for diagram 880, as it is only ever used on a road with a 30 mph speed limit. The sign to diagram 880.1 has two sizes; the smaller size is for single carriageway roads and the larger size for dual carriageway roads.
14.46 Speed enforcement should be highly visible, with drivers made fully aware of the presence of
TEMPORARY SPEED LIMITS
14.47 Where temporary speed limits are provided in connection with road works, signing should be in accordance with Chapter 8. Any reference in Chapter 8 to Traffic Advisory Leaflet 1/95 (now withdrawn) shall be taken as a reference to this chapter. The sign shown in diagram 7290 (mandatory speed limit ahead) must not be used to indicate a permanent speed limit (direction 36).
MAXIMUM SPEED ADVISED
14.48 Signs indicating the maximum speed advised must not be used to indicate a mandatory speed limit. Use of the supplementary plate to diagram 513.2 is detailed in Chapter 4 (para 3.10) and in Chapter 8 (in combination with the "loose chippings" warning sign to diagram 7009). See Chapter 8 also for the maximum speed advised signs shown in diagrams 7275 and 7294.
​SPEED LIMITS FOR TRAMCARS
976 Maximum speed limit for tramcars in kilometres per hour
The numerals may be varied. The background, border and numerals may be in any colour in accordance with the requirements of Her Majesty's Railway Inspectorate
BACKING BOARDS
14.50 To improve conspicuity against a complex or dark background, a speed limit sign may be mounted on a grey or yellow backing board (direction 42, as amended by the Traffic Signs (Amendment) General Directions 2004), although yellow backing boards will not normally be necessary when signs indicate an increase in the speed limit. A backing board can also make for a neater assembly, e.g. when the sign is mounted with the speed camera sign to diagram 879 (see figure 14-20). Other than when diagram 670 is mounted with a boundary sign to diagram 2402.1 (see para 14.51), any yellow backing board must be rectangular in shape (direction 42(6)). A sign to diagram 670 mounted on a yellow circular backing board is unlawful. A backing board must not itself be provided with a border of any kind, and no legend may be applied to it. Where it seems that a sign is not being noticed by drivers, it should be checked to ensure that it is well sited, not obscured by vegetation or other obstructions and is of the appropriate size and in good condition. Only then should the use of a yellow backing board be considered.
Figure 14-22 Example of a speed limit sign co—located with a boundary sign
14.51 Where a speed limit terminal sign to diagram 670 is mounted with a town or village boundary sign to diagram 2402.1 (not diagram 2403.1) a yellow backing board may be shaped to suit the assembly (direction 42(7)). Figure 14-22 shows a typical example. This arrangement is often used at village gateways. As drivers need to be made fully aware of the speed limit, the boundary sign has to be of a simple design to avoid being a distraction. A speed limit sign must never be incorporated within a boundary sign. If a speed limit terminal sign, to either diagram 670 or 671, is mounted back to back with the boundary sign, any irregularly shaped backing board facing drivers leaving the town or village must be coloured grey.
14.52 A yellow backing board may be reflectorised to increase its conspicuity at night. This should not usually be necessary on unlit roads, although it might sometimes be helpful on lit roads, particularly where the sign itself is unlit. It may also be fluorescent; this greatly increases conspicuity in dull weather and at dusk. Fluorescence can also be particularly effective in drawing attention to signs mounted in deep shadow, e.g. below overhanging trees. However, fluorescence is visually intrusive and should be used with ​discretion. The modern true yellow materials are less garish than the older yellow—green type and are much to be preferred.
14.53 There are potential disadvantages to the use of backing boards. The larger overall size of the assembly can sometimes obstruct sight lines. A backing board can deprive circular signs of a primary recognition aid: their distinctive silhouette. Yellow backing boards can be especially environmentally intrusive, and their over—use could eventually devalue their attention—attracting benefits. A less garish way of increasing a sign’s conspicuity is simply to provide a standard sign of larger size. Detailed guidance on the correct design and use of backing boards can be found in Chapter 7 (paras 14.19 to 14.24).
ILLUMINATION OF SIGNS
14.54 Traffic signs must be illuminated in accordance with regulation 18. Specific requirements for speed limit signs are set out in Schedule 17, items 10 and 11. Item 10 requires terminal signs to diagrams 670, 671, 672 and 673 sited on trunk and principal roads (other ”A” roads) to be illuminated by internal or external lighting throughout the hours of darkness when they are located within 50 m of a street lamp (which does not have to form part of a system of street lighting). It is insufficient to place a sign on a lighting column; a separate means of illuminating the sign face directly must be provided. However, during any time overnight that the street lamp is switched off, the sign need only be reflectorised (i.e. the sign lighting may be turned off at the same time as the street lamp). Even where the street lamp is illuminated throughout the hours of darkness, it is recommended that the sign is reflectorised in addition to being directly lit, as a precaution against a power failure.
14.55 Other terminal signs to diagrams 670, 671, 672 and 673, i.e. those on unlit roads and those on lit roads that are not trunk or principal roads, must be either directly lit or reflectorised (Schedule 17, item 11). Again, it is recommended that where a sign is directly lit it is also reflectorised. Where a road has a system of street lighting, but is not a trunk or principal road, it is recommended that speed limit terminal signs are directly lit. Although this is not a specific requirement of the Regulations, it would minimise the risk of drivers failing to see them. Repeater sign illumination is also specified in Schedule 17, item 11; signs may be either directly lit or reflectorised. It is unusual for such signs to be directly lit, although this is permitted.
14.56 20 mph zone signs to diagrams 674 and 675 may be either directly lit or reflectorised. It is recommended that where the signs are directly lit, they are also reflectorised.
14.57 Terminal speed limit signs erected in pairs must each be illuminated by the same means (i.e. internal illumination, external illumination or reflectorisation). This applies to terminal signs on each side of the road and to those erected at the same junction for the same purpose.
14.58 Where a sign is reflectorised, reflecting material must be applied to the whole sign face except those parts which are coloured black (regulation 19). The optional reflectorisation of yellow backing boards is dealt with in para 14.52.
SIGN DESIGN
14.59 Speed limit signs must conform in appearance to the diagrams prescribed by the Regulations. The numerals in diagram 670 must be in Transport heavy alphabet (Schedule 13 Part II) and be of the correct size, as specified on the working drawing P670 (see para 1.9), and be positioned within the roundel as shown on that drawing.
SIGN MOUNTING
14.60 Research has shown that the greater the number of signs that drivers are presented with simultaneously, the greater the difficulty they are likely to have in assimilating all the information. The problem of dealing with information overload increases with age, so that older drivers suffer disproportionately. Terminal speed limit signs should not therefore normally be co—located with other signs, except for simple boundary signs to diagram 2402.1 (see figure 14-22). At junctions where signs are needed to indicate the start or end of zonal restrictions or a requirement to stop or give way, these may be co—located with terminal speed limit signs if separate mounting would cause one sign to obstruct the driver's view of another. In such cases signs should be placed in the following order from top to bottom:
​(i) STOP or GIVE WAY sign
(ii) terminal speed limit sign
(iii) other circular sign
(iv) rectangular zonal sign.
Not more than one other sign should normally be erected on the same post as a terminal speed limit sign. Where a clearway sign to diagram 642 accompanied by either a distance plate or an "End" plate is mounted below a speed limit sign, the plate should be butted up against the lower edge of the clearway sign. There should be a space equal to twice the width of the red border between the roundels to ensure that there is no ambiguity.
14.61 The most cost-effective arrangement for placing speed limit repeater signs in accordance with table 14-4 is to mount the signs back to back on alternate sides of the carriageway as illustrated in the left hand part of figure 14-19. Repeater signs may be co-located with other signs such as warning signs (see para 11.26), provided the spacing requirements specified in table 14-4 are met. The repeater sign will be mounted below the warning sign. They should not normally be co-located with directional signs, as drivers searching for a destination are likely to overlook the repeater sign.
14.62 Speed limit signs should always be mounted at heights that ensure drivers can easily see them, and where they will be free from obscuration by vegetation or other street furniture. The normal mounting height for a traffic sign, measured to its lower edge, is between 900 mm and 1500 mm above the carriageway alongside (see para 1.49 in Chapter 1). It is recommended that speed limit signs should not be mounted at heights less than 1500 mm, particularly where vehicle spray is likely to soil the sign. Where speed limit signs are erected above footways, a minimum headroom of 2300 mm is recommended, with 2100 mm as an absolute minimum. A clearance of 2300 mm should be maintained over a cycle track or shared cycleway/footway. Except where necessary to improve visibility of the sign, e.g. over the brow of a hill, or to accommodate a second sign on the same post (see para 14.60), signs should not be mounted at heights greater than this. See also paras 1.29 and 1.30.
ROAD MARKINGS
14.63 The road marking roundels shown in diagram 1065 must not be used on their own, and there is no statutory requirement to use them at all. They may be used only in conjunction with the following signs:
(i) a speed limit sign to diagram 670 (when placed to indicate the point at which a speed limit begins, or as a repeater sign in accordance with direction 11(2)),
(ii) a 20 mph zone sign to diagram 674 (but not the sign to diagram 675), or
(iii) a reminder sign to diagram 880.
Further details of the road marking roundel can be found in Chapter 5 (paras 21.4 to 21.6).
14.64 The Regulations prescribe different module lengths for hazard warning lines (diagrams 1004 and 1004.1), lane lines (diagrams 1005 and 1005.1) and centre lines (diagrams 1008 and 1008.1) depending upon the speed limit. The shorter modules (diagrams 1004, 1005 and 1008) must be used where the speed limit is 40 mph or less. The longer modules (diagrams 1004.1, 1005.1 and 1008.1) must be used where the speed limit is greater than 40 mph. Whenever an order is made to change the speed limit (e.g. from the national limit to 40 mph), care should be taken to ensure that the longitudinal road markings are correct.
This work has been mirrored or sourced from material provided on the UK Government website at https://www.gov.uk/government/publications/traffic-signs-manual, which states material is available under the terms of the Open Government License unless indicated otherwise. (Crown copyright acknowledged.)
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This version was transcribed in May 2015, from a 2008 impression.
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