Speed limit signs
Introduction
The 1994 Traffic Signs Regulations and General Directions simplified the requirements for the placement of terminal and repeater signs used to indicate a speed limit, and introduced some new prescribed sizes. The intention was to give greater flexibility in the placement of signs. This would overcome the situation where signs placed marginally too far apart have had the effect of making the limit unenforceable. The 1994 Regulations thus specify simply that signs should be placed at regular intervals.
This leaflet sets out good practice on the placing of signs. It supersedes previous advice, and should be borne in mind when reviewing old signing arrangements. It is not retrospective.
Positioning Repeaters
For 30 mph lit roads, no repeaters are permitted under the regulations (Direction 10(2)(a)).
On lit roads subject to any other speed limit (other than 20mph speed limit zones), including the national speed limit, repeaters must be used. Table 1 gives recommended distances between such signs. (National speed limit signs are not required on motorways).
Table 1 - Recommended Distances between Signs
| Type of road | Maximum distance between consecutive signs on the same side of the carriageway | Maximum distance between consecutive signs on alternate sides of the carriageway | Maximum distance between start/end of length of road required to be signed and first/last repeater |
| 1. 20 mph speed limit zone - NO REPEATERS | |||
| 2. Lit 30 mph road (street lamps not more than 183 metres apart) (185 metres in Scotland) - NO REPEATERS | |||
| 3. Road more than 250 metres in length:- (i) on which the speed limit is less than 30 mph; or (ii) where there is a 30 mph speed limit, but a system of street lighting furnished by lamps placed not more than 183 metres apart (185 metres in Scotland) is not provided |
400m | 250m | 200m |
| 4. Road more than 350 metres in length:- (i) on which the maximum speed limit is 40 mph; (ii) on which a minimum speed limit is in force; or (iii) on which there is a system of street lighting furnished by means of lamps placed not more than 183 metres apart (185 metres in Scotland) and on which the national speed limit is in force |
500m | 350m | 250m |
| 5. Road more than 450 metres in length, on which a maximum speed limit of 50 mph is in force | 700m | 450m | 350m |
| 6. Road more than 500 metres in length on which the maximum speed limit is 60 mph | 800m | 500m | 400m |
| 7. Lit road more than 600 metres in length on which the national speed limit applies | 900m | 600m | 450m |
Recommended Sizes of Signs
Tables 2 and 3 indicate appropriate sizes for terminal speed limit signs placed on a continuous carriageway and at junctions. Table 4 offers advice on the sizes for repeater signs.
Table 2 - Terminal Signs
| Type of approach road | Speed limit on approach road (higher limit) (mm) |
|||
| 40mph | 50mph | 60mph | 70mph | |
| Single carriageway or one-way road | 600 | 600 | 750 (600) | - |
| Dual Carriageway up to 1km in length | 600 | 750 | 750 | 900 |
| Dual carriageway greater than 1km in length | 750 (600) | 900 (750) | 900 | 1,200 (900) |
| Motorways | - | 1,200 | 1,200 | 1,200 |
| Road works on motorways | - | 1,200 | 1,500 | 1,500 |
NOTE: Where derestriction or higher speed limit signs are mounted back to back with lower speed limit signs, the overall appearance of the assembly will be improved if the larger of the suggested sizes is used for both. The alternative sizes shown may be used where the 85th percentile speed on the approach road is at least 10mph less than the legal speed limit.
Table 3 - Terminal Signs at Junctions
| Type of approach road | Type of junction | |
| Priority and signal controlled | Free Flow (including merging lanes) | |
| Single carriageway or one way road | 450 | 600 |
| Dual carriageway | 600 | 750 |
| Motorway exit slip/on slip | 750 | 900 |
NOTE: Where derestriction or higher speed limit signs are mounted back to back with lower speed limit signs, the overall appearance of the assembly will be improved if the larger of the suggested sizes is used for both.
Table 4 - Repeater Signs
| Type of road and speed limit | Size (mm) |
| All roads 30mph and 40mph | 300 |
| Single carriageway 50mph and National Speed Limit* | 450 |
| Dual carriageway or motorway 50mph | 450 |
| Dual carriageway 60mph and National Speed Limit*, or motorway 60mph | 600 |
| Road works on motorways 40mph | 600 |
| Road works on motorways 50mph | 750 * National Speed Limit Signs |
References
The Traffic Signs Regulations and General Directions, 1994. SI No. 1519, HMSO, £24.50p Road Traffic Regulation Act 1984
Enquiries
Road Safety Division, Room C17/08A, 2, Marsham Street, London SW1P 3EB. Tel. 020 7944 8300
Welsh Office, Phase 1 Government Buildings, Ty Glas Road, Llanishen, Cardiff, CF4 5PL Tel. 0122 761456 x5237
Scottish Office, Industry Department, Road Safety Branch, New St. Andrew's House, Edinburgh EH1 3TA Tel: 0131 244 5282
The Traffic Policy/Driver Information and Traffic Management Division of the Department of Transport sponsors a wide range of research into traffic management issues. The results published in Traffic Advisory Leaflets are available to England, Wales and Scotland. Attention is drawn to variation in statutory provisions or administrative practices between the countries.
The Traffic Advisory Unit (TAU) is a multi-disciplinary group working within the Driver Information and Traffic Management Division in the Central Transport Group of the Department of Transport. The TAU seeks to promote the most effective traffic management and parking techniques for the benefits, safety and convenience of all road users.
Enquiries, and requests for unpriced TAU publications, to:
Driver Information and Traffic Management Division, 2 Marsham Street, London, SW1P 3EB, Telephone: 020 7944 8300
Within Scotland, enquiries should be made to:
The Scottish Office, Industry Department, New St. Andrew's House, Edinburgh, EH1 3TA Telephone: 0131-244 4101
