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Introduction

The purpose of this web page is to explain the legal obligations of highway authorities to provide and maintain signs to inform drivers of speed limits, so that drivers who are accused of exceeding those limits are able to check whether they are legally enforceable. A failure by a highway authority to meet the statutory requirements for the signing of speed limits could form the basis of a legal defence to a charge of exceeding a speed limit. The information that follows, however, is not qualified legal advice — if, after reading it, you believe that you have been wrongly accused of exceeding a speed limit, you should seek professional advice from a solicitor with experience of motoring cases.
 
 
 
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Legal requirements to install and maintain speed limit signs

The primary legislation which sets out the powers of highway authorities to introduce speed limits, and the requirements on those authorities to erect signs to advise drivers of the limits, is the Road Traffic Regulation Act 1984 (which will be referred to as 'the Act' from now on). The legal requirements for the signing of speed limits are set out in section 85 of the Act, and the relevant subsections are as follows:
 
(1)For the purpose of securing that adequate guidance is given to drivers of motor vehicles as to whether any, and if so what, limit of speed is to be observed on any road, it shall be the duty of the Secretary of State, in the case of a trunk road, to erect and maintain the prescribed traffic signs in such positions as may be requisite for that purpose.
(2)In the case of any road which is not a trunk road, it shall be the duty of the local authority -
 (a)to erect and maintain the prescribed traffic signs in such positions as may be requisite in order to give effect to general or other directions given by the Secretary of State for the purpose mentioned in subsection (1) above, and
(b)to alter or remove traffic signs as may be requisite in order to give effect to such directions, either in consequence of the making of an order by the Secretary of State or otherwise.
(4)Where no system of street lighting furnished by means of lamps placed not more than 200 yards apart is provided on a road, but a limit of speed is to be observed on the road, a person shall not be convicted of driving a motor vehicle on the road at a speed exceeding the limit unless the limit is indicated by means of such traffic signs as are mentioned in subsection (1) or subsection (2) above.
(7)The power to give general directions under subsection (2) above shall be exercisable by statutory instrument.
 
We will now look at the significance of these requirements. Subsections (1) and (2) place a requirement on the Secretary of State and local authorities, for trunk roads and other roads respectively, to erect and maintain speed limit signs as required by the Secretary of State. In practice, the Secretary of State's obligations in respect of trunk roads are delegated to the Highways Agency, which may employ contractors or local authorities to undertake the work.
 
The phrase 'erect and maintain' is very significant. It is not enough for speed limit signs to be installed correctly in the first place if they then disappear, become damaged or illegible, or are obscured from view, for example by foliage that is not trimmed back. Subsection (4) makes it clear that drivers cannot be convicted of speeding if the signing requirements of subsections (1) and (2) are not met. If you are charged with a speeding offence, therefore, it is advisable to check whether the signs required, as described below, are present and correct, and to seek legal advice about challenging the allegation if they are not.
 
The reference in subsection (4) to a system of street lighting, with lamps not more than 200 yards apart, concerns the way in which 30mph speed limits are indicated in built-up areas. Where a system of street lighting exists, a road is automatically a 'restricted road' under the terms of section 82 of the Act, and carries a 30mph speed limit, unless the highway authority has taken steps to revoke restricted road status and apply a different speed limit. In that case, the speed limit must be indicated by signs in accordance with subsections (1) and (2) of section 85. (In Scotland, only C-class and unclassified roads are automatically restricted roads if they have street lights. For a 30mph limit to apply on street-lit A- and B-roads, the highway authority must take positive action either to apply restricted road status or a 30mph speed limit order.) A more detailed explanation of restricted roads and the legislation relating to them can be found elsewhere on the ABD's website.
 
On roads where there is an adequate system of lighting and the default speed limit of 30mph applies, repeater signs are not allowed. This means that the street lamps themselves act as signs to indicate the speed limit. Logically, therefore, the street lamps must be visible to drivers, day or night, if they are to be aware that there is a 30mph speed limit. If it is not readily apparent that street lamps exists, for example in tree-lined roads where the lampposts cannot easily be seen, this may be a defence to a charge of exceeding the 30mph limit. We are not aware of any such cases having been contested on these grounds, so legal advice should be sought.
 
Update May 2005:
A speeding prosecution has been thrown out of court after it was proved that the speed limit was illegal.
 
Driver Phil Walker was snapped by a speed camera exceeding a supposed 30mph speed limit on the A153 in Anwick, Lincolnshire. However, traffic regulation experts proved in court that the street lighting on the road was not sufficient to give the road 'restricted' status, and that insufficient signing meant that the claimed 30mph speed limit was illegal.

Subsection 7 gives the Secretary of State powers to prescribe the signs that are necessary to advise drivers of speed limits. He does this by making a 'statutory instrument', which is legislation that does not require specific parliamentary approval, since it is authorised under the Act itself. The current statutory instrument, specifying what signs are required or allowed on the public highway (not just speed limit signs), is the Traffic Signs Regulations and General Directions 2002, which came into effect on 31 January 2003. This document will be referred to as TSRGD from now on.
 
It is important to realise that TSRGD has the same legal force as the Act itself, so its requirements are legally binding on highway authorities — they are not just guidelines or advice. If it can be shown that the signing of a speed limit does not meet the TSRGD requirements, therefore, this is a valid defence to a speeding charge.
 
We will now describe the signs that are approved under TSRGD for the purpose of indicating to drivers what the speed limit is, and how they must be used.
 
 
 
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Speed limit signs

Every sign approved for use on the public highway in TSRGD is allocated a diagram number. The two signs most commonly used to indicate a maximum speed limit are diagrams and 671, as follows:
  
 
Diagram 670
 
Diagram 671
 
Diagram 670 can indicate any speed limit from 20 to 70mph (usually in multiples of 10mph) and the signs can be from 300mm to 1500mm in diameter. Diagram 671, sometimes known as the 'derestriction' sign, has the international meaning 'end of maximum speed limit'. In the UK, however, it has been given the meaning 'national speed limit applies', which means a 60mph speed limit on single carriageway roads and a 70mph speed limit on dual carriageway roads. (A different part of the Act deals with motorway speed limits, as a result of which diagram 671 is never used on motorways.) Signs to diagram 671 can be from 450mm to 1500mm in diameter.
 
With the introduction in recent years of 20mph speed limit zones, diagrams 674 and 675 may be encountered, at the beginning and end of such a zone, as follows:
  
 
Diagram 674
 
Diagram 675
 

The bottom part of diagram 674 can show a road safety slogan instead of a place name or it may be omitted altogether. The top part of diagram 675 can show any speed limit from 20 to 70mph or it can show the 'derestriction' sign (diagram 671), as appropriate.
 
Very rarely, a minimum speed limit may be encountered. The signs to indicate the start and end of a minimum speed limit are diagrams 672 and 673, respectively:
  
 
Diagram 672
 
Diagram 673
 
Both these signs may be from 300mm to 900mm in diameter.
 
 
 
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Signs to indicate the beginning of a speed limit

Direction 8 of TSRGD sets out the requirements for the placing of signs to indicate the beginning of a restriction, requirement, prohibition or speed limit. The first paragraph of direction 8 lists the diagram numbers of the signs to which the direction applies, including diagrams 670 and 674 (See above). The other paragraphs relevant to speed limits are as follows:
(2)In accordance with the following provisions of this direction and the provisions of direction 9, appropriate signs to which this direction applies shall be placed to indicate the point at which a restriction, requirement, prohibition or speed limit applying to traffic on a road (in this direction and in direction 9 called the "relevant road") begins.
(3)Subject to paragraphs (4), (5) and (6) and to direction 9, a sign to which this direction applies shall be placed on the relevant road at or as near as practicable to the point referred to in paragraph (2) -
 (a)where the relevant road has only one carriageway, on each side of that carriageway; or
(b)where the relevant road has more than one carriageway, on each side of each carriageway in relation to which the restriction, requirement, prohibition or speed limit begins.
(4)Where the relevant road has one carriageway, then signs to which this direction applies need only be placed on one side of the relevant road to indicate the point at which a restriction, requirement, prohibition (but not a speed limit) begins in the following cases…
The remainder of paragraph (4) lists circumstances in which a sign on one side of the road only is required, but these do not apply at the beginning of a speed limit, as the wording of the paragraph makes clear. Direction 8 plainly states, therefore, that there must be a sign on both sides of the road (or both sides of the carriageway, if the road is a dual carriageway) at the point where a speed limit starts.
 
Unfortunately, there are exceptions to this rule, which are set out in direction 9 of TSRGD. The wording of direction 9 is quite complicated, so its paragraphs are reproduced below, followed by an explanation of what they mean:
(1)Direction 8(3) does not apply where a speed limit in force on the relevant road begins:—
 (a)at a point where the relevant road begins, being a point where it has no junction with another road; or
(b)at a point where the relevant road has a junction with another road and the same speed limit is in force on both roads.
The first part of this paragraph simply means that there is no need for a sign to indicate the start of a speed limit at the blind end of a cul-de-sac. The second part means that, where roads intersect and have the same speed limit, there is no need for signs to indicate the start of a speed limit, since there is no change in the limit.
(2)This paragraph applies where the relevant road has a junction ("the junction") with the side of another road ("the other road") and a maximum speed limit is in force on the other road which is different from the speed limit in force on the relevant road.
(3)Where paragraph (2) applies, it is sufficient compliance with direction 8(2), for the purpose of indicating the beginning of the speed limit on the relevant road to traffic entering it from the other road, if the sign shown in diagram 670, 674 or 675 is placed not further than 20 metres from the junction, on the left hand or near side of the carriageway of the relevant road as viewed in the direction of travel of such traffic or, where the relevant road is a dual carriageway road, on the left hand or near side of the carriageway by which traffic may pass into the relevant road from the other road.
Paragraphs (2) and (3) apply where one road has a junction with another and the two roads have different speed limits. Where traffic is turning from a major road with, for example, a 40mph speed limit, into a side turning with, say, a 30mph limit, there only needs to be a single sign at the entrance to the side road to show the start of the 30mph limit. This sign must, however, be on the left-hand side of the road as seen by drivers entering the side road, and it must be no more than 20 metres from the junction with the major road that the driver has left.
(4)Where paragraph (2) applies, for the purpose of indicating the speed limit in force on the other road to traffic entering that road from the relevant road, the sign shown in diagram 670, 674 or 675 shall (subject to paragraph (5)) be placed not further than 20 metres from the junction and so as to be visible to such traffic, on each side of the carriageway by which traffic may pass from the relevant road into the other road.
(5)Paragraph (4) does not apply if:—
 (a)the maximum speed limit in force on the other road is greater than that in force on the relevant road; and
(b)signs indicating the maximum speed limit have been placed on the other road in accordance with direction 11 on each side of, and not more than 100 metres from, the junction.
Paragraphs (2), (4) and (5) also relate to the situation where one road joins another and the two roads have different speed limits, but they deal with the signs needed to advise drivers travelling in the opposite direction, i.e. from the side road into the major road. The requirement (paragraph (4)) is for a sign to be placed on both sides of the side road on the approach to the major road, but not more than 20 metres from the junction, to show the speed limit on the major road. This only applies, however, if the speed limit on the major road is lower than that on the side road. If the speed limit on the major road is higher than that on the side road (paragraph (5)), no signs are required at all on the approach to the junction, provided there is a speed limit repeater sign on the major road not more than 100 metres from the junction, and in both directions of travel.
 
Presumably the thinking behind this exception is that drivers entering the major road will assume that the speed limit has not changed, until they see a speed limit repeater sign. If the major road is of a much better standard than the side road, however, drivers are likely to expect that a significantly higher speed limit applies and could accelerate to above the actual limit before they see the first repeater sign. The real purpose, of course, is to save the highway authority money in the provision of signs.
 

Examples

In order to show how speed limits should be signed at junctions, in accordance with TSRGD, the following diagrams may be helpful. The first one shows a simple tee-junction between a major road and a minor road. The major road has a 30mph speed limit and the minor road a 40mph speed limit, so drivers joining the major road are entering a lower speed limit.
 
         
Major Road (30mph speed limit)
   
20m
max
         
  Minor Road
(40mph
speed
limit)
 
 

 

 
 
In the second example, the major road has a 40mph speed limit but the minor one has a 30mph limit, so drivers from the minor road are entering a higher speed limit. If the major road had a national speed limit (60mph on a single carriageway or 70mph on a dual carriageway) the requirements would be different. These are explained later.
 
      ←100m max→
Major Road (40mph speed limit)
←100m max→    
20m
Max
   
      Minor Road
(30mph
speed
limit)
 
 
 
 
 
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Speed limit repeater signs

The use of repeater signs is governed by direction 11 of TSRGD. The first paragraph of this direction lists the diagram numbers of the signs to which the direction applies, including diagram 670. The remaining paragraphs of direction 11, as they affect the requirements for speed limit repeater signs, are reproduced below, followed by an explanation of what they mean:
(2)Subject to paragraphs (3) and (4), signs to which this paragraph applies shall be placed at regular intervals along a road which is subject to a restriction, requirement, prohibition or speed limit which can be indicated by the signs.
Paragraphs (3) and (4), referred to within this paragraph, relate to the special cases of 20mph speed limit zones and 30mph speed limits in built-up areas. These are described in detail below.
 
The phrase 'at regular intervals' is not defined in TSRGD, but the former Department of the Environment, Transport and the Regions issued guidance to highway authorities in 1995 (Traffic Advisory Leaflet 01/95: Speed Limit Signs). This leaflet includes a table showing the recommended distances between consecutive repeater signs and between the first/last repeater signs and the start/end of a speed limit. Different recommendations apply according to the type of road. These recommendations are reproduced in the table that follows.
 

Type of road Max. distance between consecutive signs on the same side of the carriageway Max. distance between consecutive signs on alternate sides of the carriageway Max. distance between start/end of length of road required to be signed and first/last repeater
Road more than 250m in length:
(i) on which the speed limit is less than 30mph; or
(ii) where there is a 30mph limit, but a system of street lighting is not provided (or lights are more than 200 yards apart)
400m 250m 200m
Road more than 350m in length:
(i) with a maximum speed limit of 40mph; or
(ii) with a minimum speed limit; or
(iii) where a system of street lighting is provided (lamps not more than 200 yards apart) and the national speed limit applies
500m 350m 250m
Road more than 450m in length with a 50mph speed limit 700m 450m 350m
Road more than 500m in length with a 60mph speed limit 800m 500m 400m
Lit road more than 600m in length on which the national speed limit applies 900m 600m 450m
 

Note that the requirement to provide repeater signs to indicate that a road is subject to the national speed limit only applies if the road has a system of street lights (lamps not more than 200 yards apart). In this case the sign used is the 'derestriction' sign, known in TSRGD as diagram 671. The purpose of providing signs in these circumstances is to advise drivers that the road is not subject to a 30mph speed limit, which a system of street lighting normally implies.
 
The distances shown in the Traffic Advisory Leaflet and reproduced in the table above are not themselves legally enforceable requirements. However, if the distances between repeater signs were significantly greater than those shown, that fact could be presented in court as evidence that the highway authority had failed to meet the requirement under direction 11 to provide repeater signs 'at regular intervals'.
 
 
 
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20mph zones

There is a legal distinction between a 20mph speed limit and a 20mph zone, as far as signing requirements are concerned. A 20mph speed limit is signed in exactly the same way as any other, i.e. there must be a pair of signs at the point where the speed limit starts, one each side of the road (except in some circumstances within 20 metres of a junction, where only one sign is required — see above), and repeater signs must be provided at intervals.
 
A 20mph zone, however, must have zone entry signs at each point where drivers can enter the zone. These signs must be in accordance with diagram 674 of TSRGD, instead of the normal sign denoting a maximum speed limit, diagram 670. Zone exit signs, in accordance with diagram 675, should be placed at every exit point, for the benefit of drivers leaving the zone.
 
Direction 11 of TSRGD, paragraph (3), states:
(3)Signs shown in diagram 670 when varied to "20" need not be placed in accordance with paragraph (2) on a road within an area into which each entrance for vehicular traffic has been indicated by the sign shown in diagram 674.
This means that there is no requirement for speed limit repeater signs to be provided within a 20mph zone, even though such zones will almost invariably be in street-lit areas, where the presence of street lamps and the absence of repeater signs should normally be taken by drivers as evidence of a 30mph speed limit. The wording 'need not be placed' does not prohibit the provision of repeater signs, but most highway authorities are likely to take advantage of the provision in this paragraph to save money on signs.
 
Although the lack of repeater signs within 20mph zones could, therefore, lead to drivers believing that they are in a 30mph speed limit, these zones are intended to be self-enforcing, and traffic calming measures must be installed where necessary to physically restrain traffic speeds to within the speed limit. A 20mph speed limit, on the other hand, does not have to be self-enforcing in this way.
 
The requirements for 20mph zones to be self-enforcing are quite specific and are set out in Direction 16 of TSRGD, which applies to diagram 674:
(1)The sign shown in diagram 674 may only be placed on a road if no point on any road (not being a cul-de-sac less than 80 metres long), to which the speed limit indicated by the sign applies, is situated more than 50 metres from a traffic calming feature.
(2)In paragraph (1) "traffic calming feature" means -
 
 (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.
(3)For the purposes of paragraph (1) the distance of 50 metres shall be measured along roads to which the speed limit indicated by the sign shown in diagram 674 applies.
What this means in plain English is that, within a 20mph zone, traffic calming features must be no more than 100 metres apart (so that the mid point between them is no more than 50 metres from such a feature in either direction). There must also be no more than 50 metres between every entry point to the zone and the first traffic calming feature, although many zones combine the entry point with some sort of traffic calming device.
 
The 'traffic calming works' referred to in paragraph (2)(b) are defined in the Traffic Calming Regulations as build-outs, chicanes, gateways (England and Wales only), islands, overrun areas, pinch-points, or rumble devices, or any combination of these. These terms are defined in the Traffic Calming Regulations as follows:
"build-out" means a work for narrowing a carriageway constructed on one side of the carriageway as an extension of or adjacent to the verge, footway or cycle track;
"chicane" means a series of two or more build-outs constructed on alternate sides of a carriageway and not opposite one another;
"gateway" means an object or structure constructed on the verge, footway or cycle track of a highway for the purpose of indicating the presence in a length of highway of traffic calming works of a description prescribed by these Regulations or specially authorised by the Secretary of State or a road hump;
"island" means a work without facilities for pedestrians constructed in a carriageway to reduce carriageway width or to deflect the flow of vehicular traffic;
"overrun area" means an area of carriageway so constructed of textured or coloured material as to appear to narrow that carriageway;
"pinch-point" means build-outs constructed on both sides of a carriageway opposite one another;
"rumble device" means a part of the carriageway constructed of material intended to generate noise or vibration in a vehicle passing over it.
Since the exacting requirements of direction 16 are legally binding, if they are not met it follows that the 20mph speed limit within the zone would be unenforceable, as use of the sign indicating the start of the zone (diagram 674) would not be legal.
 
 
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30mph speed limits in built-up areas

Built-up areas where there is street lighting and a 30mph speed limit are the major exception to the requirement to provide speed limit repeater signs. Direction 11 of TSRGD, paragraph (4), states:
 
(4)The sign shown in diagram 670 (except when displayed on a variable message sign in the manner mentioned in regulation 58(7)(b)) shall not be placed along —
 (a)a road on which there is provided 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 and which is subject to a speed limit of 30mph;
Note that 'shall not be placed' means that repeater signs are prohibited under the conditions specified in subparagraph (a), not just that they are not required. The 183 metre maximum spacing for street lamps in England and Wales is the metric equivalent of the 200 yards specified in the Act.
 
The reference in the subparagraph to a system of 'carriageway' lighting is potentially significant. The carriageway is that part of the highway intended for the use of vehicles, as defined in section 329 of the Highways Act 1980, so a system of carriageway lighting must be designed to illuminate the roadway itself and not just the footways. The 1980 Act, section 270, defines a 'footway lighting system' and a 'road lighting system' as follows:
"footway lighting system" means a system of lighting, provided for a highway, which satisfies the following conditions, namely, that either —
(a)no lamp is mounted more than 13 feet above ground level, or
(b)no lamp is mounted more than 20 feet above ground level and there is at least one interval of more than 50 yards between adjacent lamps in the system;
"road lighting system" means a lighting system that is not a footway lighting system.
Subparagraph (a) makes it clear that, where street lamps are less than 13 feet (3.96 metres) high, they constitute a footway lighting system, not a 'road' lighting system, regardless of their spacing. (In this context, 'road' is synonymous with 'street' or 'highway', in meaning any part of the carriageway, footways and verges. Thus a 'road lighting system' would include a carriageway lighting system, but a 'footway lighting system' would not.)
 
Subparagraph (b) says that, where street lamps are between 13 feet (3.96 metres) and 20 feet (6.1 metres) high, they constitute a road lighting system only if there are no gaps greater than 50 yards (45.7 metres) between any pair of lamps in the system. Only street lamps higher than 20 feet (6.1 metres) automatically qualify as a road lighting system, subject to the 183 metres maximum spacing in direction 11, paragraph (4)(a) of TSRGD.
 
As described further on, direction 37 of TSRGD sets out the circumstances in which a temporary sign may be placed to warn drivers of a new 30mph speed limit in a built-up area. This direction includes wording virtually identical to that in direction 11, paragraph (4)(a), except that it refers to 'a system of street or carriageway lighting', not just to carriageway lighting. It could be, therefore, that there is an error in the drafting of direction 11, which means that 30mph repeater signs are required where only a footway lighting system exists.
 
As far as we know, this defence to a charge of exceeding a 30mph speed limit in a built-up area has not been tested in court. It would not have arisen under the previous edition of TSRGD, in which the prohibition on repeater signs, in England and Wales, applied to 'restricted roads'. The definition of a restricted road is given in section 82(1) of the Act as one on which there is a system of street lighting, with lamps not more than 200 yards apart. This would include a footway lighting system.
 
Where repeater signs are forbidden and the street lights themselves are used to indicate to drivers that a 30mph speed limit exists, it follows that the presence of those street lights must be clear to drivers, during the daytime as well as at night. If this is not the case, the highway authority might be in breach of its duty under section 85(1) of the Act to erect and maintain the necessary signs to advise drivers of the speed limit.
 
 
 
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Signs to indicate the end of a speed limit

In many cases, where one speed limit ends another begins, so the signs required at the end of the first speed limit are those required to show the start of the second. Where a speed limit ends and a national speed limit begins, however, there are different requirements in some circumstances.
 
The requirements for placing signs at the end of speed limits are set out in direction 10 of TSRGD. The relevant paragraphs are as follows, followed by an explanation of their meaning:
(2)Subject to paragraph (3), where a length of road ceases to be the subject of a speed limit and becomes subject to a national speed limit, the sign shown in diagram 671 shall be placed at or as near as practicable to the point where the speed limit ends and the national speed limit begins.
Paragraph (3) concerns signs required at the end of temporary speed limits, such as those at road works. These are discussed in a separate section below. The remainder of paragraph (2) is self-explanatory. Diagram 671 is the 'derestriction' sign.
(4)When the sign shown in diagram 671, 673 or 675 is placed to indicate the point at which traffic on a road ceases to be subject to a speed limit —
 (a)where the road has only one carriageway, one such sign shall be placed on each side of the carriageway of the road; or
(b)where the road has more than one carriageway, one such sign shall be placed on each side of each carriageway on which the speed limit ends.
Diagram 673, referred to, indicates the end of a minimum speed limit and diagram 675 indicates the end of a 20mph zone. Paragraph (4) specifies that signs to show the end of a speed limit must be placed on both sides of the road, in the same way as those required to show the start of a speed limit. However, there are exceptions to this rule where the speed limit ends at a junction:
(5)Where a road ("the relevant road") has a junction with the side of another road ("the other road") and —
 (a)a maximum speed limit is in force on the other road; and  
(b)a national speed limit is in force on the relevant road,  
then, for the purpose of indicating the national speed limit to traffic entering the relevant road from the other road, the sign shown in diagram 671 or 675 shall be placed on the relevant road in accordance with paragraph (6).
(6)The sign shall be placed not more than 20 metres from the junction with the other road on the left hand or near side of the relevant road as viewed in the direction of travel of a vehicle entering the relevant road from the other road or, if the relevant road is a dual carriageway road, on the left hand or nearside of the carriageway by which a vehicle may pass into the relevant road from the other road.
This means that, where a driver turns from a road with a maximum speed limit into one with a national speed limit, only one 'derestriction' sign needs to be provided, on the left hand side of the road. This is analogous to the situation where a speed limit on a side road starts at its junction with a main road, as shown in a previous section.
 
At junctions where the main road is subject to a national speed limit but the side road has a maximum speed limit, the requirements are set out in paragraphs (7) and (8):
(7)Where the relevant road has a junction with the side of the other road and —
 (a)a national speed limit is in force on the other road; and
(b)a maximum speed limit is in force on the relevant road,
then, for the purpose of indicating the national speed limit to traffic entering the other road from the relevant road, traffic signs shown in diagram 671 or 675 shall be placed in accordance with paragraph (8) on the relevant road not further than 20 metres from the junction.
(8)If the relevant road has one carriageway, one such sign shall be placed on each side of that carriageway and, if the relevant road is a dual carriageway road, one such sign shall be placed on each side of the carriageway by which traffic may pass from the relevant road into the other road.
This means that there has to be a pair of signs on the minor road, not more than 20 metres from its junction with the major road, to show that the national speed limit applies on the major road. This is different from the situation where the major road has a maximum speed limit higher than that on the minor road, as there will be no speed limit repeater signs on the major road where the national speed limit applies, unless there is street lighting. (See above)
 

Examples

To illustrate the requirements at junctions as described above, the following examples may be helpful. In the first one, the major road has a 40mph speed limit and the minor road is subject to the national speed limit:—
 
         
Major Road (40mph speed limit)
   
20m
max
         
  Minor Road
(National
Speed
Limit
Applies)
 
 

 

 

In the second case, the minor road has a 40mph speed limit and the major road is subject to the national speed limit:—
 
         
Major Road (National Speed Limit Applies)
   
20m
max
         
  Minor Road
(40mph speed limit)
 
 

 

 

 
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Speed limit signs on motorways

Motorways are classed as 'special roads' and the Secretary of State's powers to apply a maximum speed limit on them are contained in a different section of the Act from that used to apply speed limits on ordinary roads. Consequently, some of the sections of the Act that apply to speed limits generally do not apply to motorways, resulting in some of the requirements of TSRGD not applying either.
 
The most significant difference in the legislation relating to motorways is that the provision of a system of street lighting does not automatically result in a 30mph speed limit being applied, as it would do on ordinary roads. There is no requirement, therefore, to install 'derestriction' repeater signs (diagram 671) along lengths of motorway with street lamps, as there is on ordinary roads where the national speed limit applies. Indeed, paragraph (4)(b) of direction 11 of TSRGD specifically prohibits the use of this sign on motorways.
 
On motorways where the normal speed limit of 70mph applies, therefore, the only speed limit signs required are those to diagram 670, showing the figure "70", at the point where a motorway starts and at the start of every entry slip road.
 
The two signs shown below (diagrams 2901 and 2931) are used at the start and end of motorways, respectively:
 
 
Diagram 2901
 
Diagram 2931

These signs indicate the points at which motorway regulations start and end, in accordance with the provisions of section 17 of the Act. That section gives the Secretary of State powers to make traffic regulations on special roads, including speed limits. It could be argued, therefore, that the presence of a sign to diagram 2901 notifies drivers that a speed limit of 70mph applies. However, there are no provisions within direction 8 of TSRGD to exempt special roads from the requirement to provide signs to diagram 670 at the start of a speed limit. Consequently, it is our view that "70" signs are specifically required at every entry point to a motorway.
 
At every point where a motorway ends, a sign to diagram 2931 must be provided and, if a speed limit other than 70mph is being entered, signs to diagram 670 are required in the normal way (or diagram 671, if the national speed limit applies), to show the speed limit being entered. In a case where a motorway ends and runs directly into an all-purpose dual carriageway, a pair of signs to diagram 671 (the 'derestriction' sign) should also be provided. However, the absence of such signs is unlikely to offer a defence to exceeding the national speed limit on the dual carriageway, since the last speed limit sign the driver passed should have been a "70" sign at the start of the motorway.
 
The only circumstances in which speed limit signs will be encountered along a motorway, apart from at the entry and exit points, are where a speed limit lower than 70mph applies, as is sometimes the case on urban motorways, and temporarily at road works. In those cases, the normal requirements apply with regard to signs at the start and end of the speed limit, and to repeater signs.
 
 
 
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Speed limit signs at road works

For the most part, temporary speed limits at road works must be indicated by signs in the same way as permanent speed limits. This means there must be a pair of signs at the start of the speed limit and repeater signs at intervals.
 
At the end of a temporary speed limit, however, there are different requirements, which are set out in paragraph (3) of direction 10 of TSRGD, as follows:
(3)Where a temporary restriction of speed has been imposed under section 14 of the 1984 Act along a length of road by reason of works which are being or are proposed to be executed on or near that road, there shall be placed at or as near as practicable to the point where the temporary restriction of speed ends —
 (a)the sign shown in diagram 7006 or in diagram 7001 (placed in combination with the plate shown in diagram 645); and
(b)in a case, where, but for the temporary speed limit, a change in speed limit would at some point have occurred along the length of road, the sign shown in diagram 670 (varied as appropriate) or 671.
The signs referred to in subparagraph (a) are as follows:
 
 


Diagram 7006
 
Diagram 7001
with diagram 645

In a situation where the temporary speed limit covers a section of road that would normally have one permanent speed limit throughout its length, all that is required to mark the end of the temporary restriction is one of the above signs. If the permanent speed limit changed at some point along the length of the temporary restriction, however, signs to diagram 670 (maximum speed limit) or 671 (national speed limit) must be shown in addition, to show what the permanent speed limit is as drivers leave the temporary restriction. If either of these signs are required, they must be shown as a pair, one each side of the road (or carriageway, in the case of a dual carriageway). Signs to diagram 7006 or 7001 (with the 'End' plate of diagram 645) need only be displayed singly.
 

Examples

In order to illustrate these requirements, the following examples show the signs required along a length of one carriageway of a dual carriageway road. In the first example, the permanent speed limit on the road is the national speed limit (70mph) throughout its length and the temporary speed limit is 40mph. The direction of travel is from bottom to top.
       
  End of temporary speed limit   
       
  Repeater signs at regular intervals  
   
   
       
  Start of temporary speed limit
       
    National speed limit applies  

In the second example, the carriageway is normally subject to a 50mph speed limit on the first half of the section covered by the temporary speed limit, but the national speed limit for a dual carriageway road (70mph) applies on the second half of the section. The temporary limit is again 40mph and the direction of travel is from bottom to top.
       
   
  End of temporary speed limit   
       
  Repeater signs at regular intervals  
   
   
       
  Start of temporary speed limit
       
    50mph speed limit  

 
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Lighting of speed limit signs

The requirements concerning the lighting of speed limit signs are contained in Schedule 17 of TSRGD, items 10 and 11. Item 10 applies to signs indicating maximum, minimum and national speed limits (diagrams 670, 671, 672 and 673). Item 10 is reproduced below, followed by an explanation of its meaning:
(1)Where the sign is a terminal sign and is erected on a trunk or principal road within 50 metres of a street lamp lit by electricity, it shall throughout the hours of darkness —
 (a)be continuously illuminated by means of internal or external lighting and may also be reflectorised; or
(b)while the street lamp is lit, be continuously illuminated by means of external lighting and shall also be reflectorised.
(2)If any sign is required to be illuminated in the manner and at the times described in paragraph (1) above —
 (a)every sign shown in the same diagram as the first-mentioned sign which is erected at or near the same point on the road or the same junction for the same purpose as the first-mentioned sign shall be continuously illuminated throughout the same period by the same means of lighting as the first-mentioned sign; and
(b)if any of the signs is reflectorised, every other such sign shall be similarly illuminated.

Paragraph (1) of this item means that a sign at the beginning or end of a speed limit must be positively illuminated, i.e. it must not rely solely on the use of reflective material, if the sign is within 50 metres of a street lamp — but only on a trunk or 'principal' road. There is no certain way of knowing whether a road is a principal road without checking with the local highway authority, but in general terms all primary routes (those with green-backed direction signs) and most other A-roads are either trunk or principal roads.
 
Subparagraphs (a) and (b) of paragraph (1) give highway authorities a choice between internal or external illumination of the sign and the use of reflective material. The trend these days is towards external illumination of reflectorised signs.
 
Paragraph (2) of item 10 sounds very complicated but all that it means is, where more than one sign is located at the same place on the road, all those signs must be illuminated in the same way and for the same period of time. For example, at the start of a speed limit there must usually be a sign on both sides of the road, so where illumination is required, both signs must be illuminated in the same way.
 
Item 11 of Schedule 17 applies to the same signs as item 10, but additionally it applies to the signs indicating the start or end of a 20mph zone (diagrams 674 and 675). Item 11 is reproduced below, followed by an explanation of its meaning:
 
If the sign is not required by item 10 to be illuminated by lighting throughout the hours of darkness or throughout such hours while a street lamp is lit, it may be illuminated by a means of internal or external lighting; but if not so illuminated, it shall be reflectorised in accordance with regulation 19.
Paragraph (2) of item 10 shall apply as if the sign were a sign required by paragraph (1) of item 10 to be illuminated by lighting throughout the hours of darkness or throughout those hours while a street lamp is lit.

What this means is that signs may be illuminated, either internally or externally, even if they are not required to be under item 10, but if they are illuminated then all signs at the same location must be illuminated in the same way. All speed limit signs that are not illuminated must be made of reflective material.
 
To summarise, lighting of speed limit signs is only compulsory at the start and end of speed limits on trunk and principal roads, where those signs are within 50 metres of a street lamp. There is no requirement to illuminate repeater signs or the signs at the entry or exit of a 20mph zone, regardless of the class of road. Speed limit signs that are not illuminated, however, must be reflectorised.
 
 
 
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Signs to indicate newly introduced speed limits

With many existing speed limits being reduced or extended, and new ones being introduced, drivers can easily fail to realise that a speed limit has changed, especially if they have used a road on a regular basis for a long time and are accustomed to the old speed limit. This is especially true in built-up areas with street lighting, where a 30mph speed limit may have replaced a higher limit. Since repeater signs are not permitted in 30mph speed limits on street-lit roads, a change from a higher speed limit to a 30mph limit requires only the removal of the signs indicating the higher limit. The removal of the old signs can easily go unnoticed by drivers.
 
In the edition of TSRGD that came into effect on 31 January 2003, a new sign, diagram 7032, is authorised for use at the start of a new 30mph speed limit on a street-lit road, under certain circumstances. The sign is as follows:
 
Diagram 7032

Direction 37, paragraph (2), of TSRGD sets out the circumstances in which a sign to diagram 7032 may be used:
The sign shown in diagram 7032 —
(a)may be placed only to indicate the point at which a recently imposed speed limit of 30mph begins on a road —
(i)on which there is a system of street or 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; and
(ii)which had previously been subject to a higher speed limit;
(b)shall be placed as near as practicable to that point;
(c)shall not be placed unless that point could not otherwise be indicated in accordance with these Directions;
(d)may be placed only during the period of 6 months beginning with the day on which the 30mph speed limit comes into force; and
(e)shall not be retained after the end of that period.
The provisions of this direction mean that a sign to diagram 7032 may be placed at the start of a recently imposed 30mph speed limit on a street-lit road that previously had a higher speed limit, although it is not compulsory. It can only be placed at the start of the new speed limit — not at intervals throughout its length as a repeater sign — and only if no other form of signing is required at that point under TSRGD. Furthermore, it can only be displayed for a maximum period of six months.
 
These limitations on the use of the sign appear almost to have been designed to give drivers the minimum opportunity to be made aware of a change in speed limit. The following diagrams show a typical situation where there had previously been a length of 40mph speed limit adjacent to a 30mph limit; the 40mph limit is then reduced so that the whole length of road is subject to a 30mph limit.
 
Before
 
           
NSLA 30mph limit 40mph limit NSLA
           
 
After
 
             
NSLA 30mph limit NSLA
                 
 
Thus drivers entering the new 30mph limit from the existing one have only one chance (if that) to realise that the limit has changed — if they miss seeing that one sign, assuming there is one, they may continue at 40mph in ignorance of the change. This in our view is indefensible, and even more so if no sign is installed at all. There was a case in Kidderminster in 2002 where a 40mph limit was reduced to 30mph on the A449 and no signs warning of the change were installed. A large number of drivers were caught exceeding the new limit and one of them went to court, where it was agreed that the highway authority had acted unreasonably by not making drivers aware of the change. The police had to refund all the fines.
 
Some highway authorities have installed temporary rectangular signs with the words "New speed limit" on a blue background, at intervals throughout new speed limits. This type of sign does not appear as a permitted sign, however, in either the existing edition of TSRGD or the previous one, so it may have been approved by the Department for Transport on an individual basis, or highway authorities may have used it illegally. We consider that all new speed limits should be adequately signed for a minimum of six months after they come into force. Despite the restrictions in TSRGD on the use of such signs, drivers who are charged with exceeding a new speed limit where there is inadequate warning of the change should seek legal advice on the possibility of challenging the prosecution.
 
 
 
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Combinations of signs and the use of backing boards

The TSRGD allows signs to be mounted on yellow or grey backing boards to improve their visibility. It is also permissible for two or more different signs to be mounted on one backing board. To be legal, however, the following conditions must be met: There has been at least one instance where a local authority combined a speed limit repeater sign with a camera warning sign on a yellow board, with a black border around it. This was deemed to be illegal by the courts and the speed limit was unenforceable as a result.
 
The specific requirement for yellow backing boards to be rectangular was included in the 2002 version of TSRGD for the first time (direction 42(6)). At least one local authority (Leicestershire) has used circular backing boards to diagram 670 speed limit signs for many years. Although the 1994 edition of TSRGD did not specifically say that backing boards must be rectangular, the use of circular boards around a circular sign (such as diagram 670) was still considered to be illegal, because the circle of yellow around the outside of the sign was construed as an additional 'border', thereby changing the appearance of the sign as prescribed. It therefore becomes an unauthorised sign.
 

Legal

Legal

Illegal
Where signs with circular yellow backing boards have been installed since 31 January 2003 (when the latest edition of TSRGD came into effect), there can be no question whatsoever that they are illegal. This includes signs replacing damaged ones installed before that date. Signs installed before 31 January 2003, if they had been legal at the time of installation, might have continued to be so under the 'savings' provisions within the regulations (until maintenance replacement). However, the Department for Transport's view is that these signs are not legal.
 
There is one exception to the rule that a yellow backing board must be rectangular : signs showing the name of a town or village that drivers are entering may be mounted on backing boards of any shape, including rectangular. An amendment to the TSRGD published in 2004, that came into force on 27th May 2004, made it clear that this exception extends to a combination of a place name sign and a diagram 670 speed limit sign on a single board. Thus this 'gateway' sign for Peckleton in Leicestershire is legal.
 
 
In the specific case of 30mph speed limits on roads with street lighting, where speed limit repeater signs are forbidden (see above), the combined sign below is permitted by TSRGD where speed cameras are in use.
 

Diagram 880

The use of this sign is governed by direction 32(2), which states:
(2)The sign shown in diagram 880 may be placed only —
(a)on or near a road on which there is provided a system of carriageway lighting furnished by means of lamps placed not more than 183 metres apart in England and Wales or 185 metres apart in Scotland and which is subject to a speed limit of 30mph; and
(b)not more than one kilometre from a site at which an enforcement camera has been installed and is from time to time in use, and not more than two such signs may be so placed on each approach to that site.
Sub-paragraph (b) limits the use of diagram 880 to just two signs on each approach to fixed locations where cameras operate from time to time. Moreover, the words 'may be placed' means that there is no legal requirement within TSRGD to install them, although such a requirement is included in the guidance to the safety camera partnerships.
 
There are some other signs specifically authorised within TSRGD that do combine a number of individual signs on a yellow board surrounded by a border. One such sign is that authorised for use at the end of road works, diagram 7006.
 
Examples of combined signs, showing those that are legal and those that are not, can be found on the Safespeed website.
 
 
 
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Road markings associated with speed limits

In addition to signs displayed alongside or above a road to indicate speed limits, TSRGD specifies how certain carriageway markings must be varied according to the speed limit. (Legally, carriageway markings are defined as 'traffic signs' just as much as those mounted on posts.) Three types of road marking differ according to whether the speed limit is 40mph or less, or greater than 40mph. These are:
In all cases, the difference between the markings with speed limits of 40mph or less and speed limits above 40mph is in the length of the individual markings and the gaps between them. Normal centre line markings are shown in TSRGD as diagram 1008 (speed limit 40mph or less) and 1008.1 (speed limit greater than 40mph).
 
← 2m →← 4m →← 2m →
Diagram 1008
 
← 3m →← 6m →← 3m →
Diagram 1008.1

In both cases, the gap between the markings is twice the length of each marking. For lower speed limits there must be a 2-metre mark and a 4-metre gap; for higher speed limits the marks are 3 metres long and the gaps 6 metres long. In either case, the white lines are normally 100mm (4 inches) wide, but the width may be increased to 150mm (6 inches).
 
 
For 'hazard' centre line markings, the lengths of the marks and gaps are reversed: the mark is twice as long as the gap. Thus, for roads with a speed limit of 40mph or less (diagram 1004), the marks must be 4 metres long separated by gaps of 2 metres; for speed limits above 40mph (diagram 1004.1) the marks must be 6 metres long and the gaps 3 metres long. The same width requirements of 100mm and 150mm apply.
 
← 4m →← 2m →← 4m →
Diagram 1004
 
← 6m →← 3m →← 6m →
Diagram 1004.1

 
Markings that divide traffic lanes on a road with a speed limit of 40mph or less (diagram 1005) must be 1 metre long, separated by gaps of 5 metres. For speed limits above 40mph (diagram 1005.1), the markings must be 2 metres long separated by gaps of 7 metres. Again, the normal marking width is 100mm but this may be increased to 150mm.
 

1m
← 5m →
1m
Diagram 1005
 
← 2m →← 7m →← 2m →
Diagram 1005.1

 
With all three types of marking, the requirements of TSRGD 2002 are unchanged from the 1994 version. Since few road markings survive more than about five years without the need for replacement, local authorities cannot claim that any incorrect markings are legal under the 'savings' provisions contained within the regulations. (Regulation 3 of TSRGD allows a sign that was in place before the 2002 regulations came into effect to remain lawful if it complied with either the 1981 or 1994 regulations, until such time as it requires replacement during normal maintenance.)
 
Where a speed limit is changed from above 40mph to 40mph or less (or vice versa), the highway authority has an obligation to amend any road markings that exist to comply with the requirements of the new speed limit. In some cases this may require extensive burning-off of old markings and replacement with correct ones. It is likely that many authorities fail to do this, either due to ignorance of the legal requirements or in order to save money. If challenged, they cannot rely on the savings provisions in regulation 3, since the old markings would still have been illegal for the new speed limit under previous versions of TSRGD.
 
All three types of marking described above are required, under Schedule 17 (item 12) and regulation 31 of TSRGD, to be of reflectorised material.
 
Not all roads have centre line markings, especially minor and residential roads, but where markings are provided they must comply with the requirements set out above.
 
Speed limit roundels
 
Road markings to supplement speed limit signs are permitted in some circumstances. Elongated roundels (diagram 1065 of TSRGD shown right), which appear round to an approaching driver, may be provided in one of two sizes.
 
The figure in the roundel may, instead of showing 30mph, be varied where appropriate to show 20, 40 or 50 mph and, on dual carriageways only, 60 mph. It may not be used to show the national speed limit of 60mph on a single carriageway road. The use of these roundels is governed by direction 18(1) of TSRGD, which permits their use only in conjunction with speed limit signs to diagram 670, whether at the start of a speed limit or as repeater signs.
 
The effect of this restriction is, firstly, that carriageway roundels may not be used as repeater signs on street-lit roads with a 30mph speed limit, since speed limit repeater signs are not allowed on these roads (see above). Secondly, the use of roundels alone is not permitted — they can only be used as additions to normal speed limit signs, not in place of them. A speed limit would not be enforceable, therefore, if roundels were provided instead of repeater signs.
 
There are exceptions to this last rule: in the New Forest, for example, the Secretary of State has authorised the use of roundels alone to act as repeater signs for the 40mph speed limits that apply along many of the roads through the area. There may be similar special authorisations in other areas of particular scenic value. If in doubt, the local highway authority should be asked for proof that such authorisation has been granted.
 

 
 
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Action to take in the case of faulty signs

If you have been charged with a speeding offence and, after reading the information on this page, you believe that the speed limit signs at the time did not comply with the regulations, you should obtain as much evidence as possible about the deficiencies and then consult a solicitor who specialises in motoring offences. The ABD has a list of solicitors known to be helpful to drivers, although there may well be others.
 
Photographic evidence is especially useful where signs are missing (e.g. only one sign at the start of a speed limit where there should be two) or invisible to drivers (e.g. where foliage obscures the sign). The date when any photographs are taken should be recorded and preferably verified by a witness.
 
Measurements may also be useful if, for example, street lamps are more than 200 yards apart in a 30mph area and there are no repeater signs; or where repeater signs are significantly further apart than the recommended distances; or where speed limit entry signs may be within 50 metres of a street lamp on a trunk or principal road but are not illuminated.
 
Obviously such evidence should be collected as soon as possible after the alleged offence, to minimise the possibility that conditions might have changed in the intervening period. If signs which you believed were missing or could not be seen at the time of the alleged offence appear to have been replaced or made visible subsequently, you would need to contact the highway authority to get confirmation of when the sign was installed or the maintenance work carried out.
 
Even if you have not been charged with a speeding offence but you have noticed that a particular speed limit appears to be incorrectly signed, you might wish to bring the matter to the attention of the highway authority. This will usually be the county council (or unitary authority, if there is one), unless the road is a trunk road, in which case you should contact the appropriate regional office of the Highways Agency. If you are not sure, just write to the nearest local authority and they will forward your letter.
 
Your letter should be as precise as possible about the nature of the defects, quoting the aspects of legislation that are not complied with. You should make it clear that you consider the speed limit to be unenforceable as a consequence. Copy your letter to the police: if they continue to enforce a speed limit when they have been advised that it does not meet the legal requirements with respect to signing, and someone brings this out in court, it could have serious consequences for them. Naturally, keep a copy yourself and, if possible, keep an eye on local press reports for speeding convictions on the road in question.
 
 
One of the letters we've received regarding this issue:
Dear ABD,
 
Last November I was "caught" speeding at 42mph in a 30 mph zone. At the time I was angry with myself, but as most people do, went to pay the fine and accept the 3 points.
 
When I came to produce on the 7th day the police station had closed early. When I went to produce on the 8th day I was told I was too late and I would have to attend court.
 
Between being "caught" and attending court I discovered your website and went through the law regarding the positioning of speed limit signs.
 
I then retraced my journey when I was stopped and realised that the road leading into the road in which I was stopped had incorrect speed signs. The speed had been reduced from a 40mph to a 30mph but only one sign post was present, it was on the right hand side of the road, and it wasn't illuminated. Thus making the reduction almost invisible (I was stopped at night)
 
From the information I downloaded from your website, I represented myself in court and low and behold I won. No fine and no points.
 
The most valuable piece of evidence I had in court was a photograph of the scene with the "missing" sign post.
 
I hope my experience will encourage others to at least make sure that the regulations have been followed by the highways agency and the local council before they automatically pay their fines.
 
Many thanks for your information, my membership application is on its way.
 
S.H.

 
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