# Traffic Signs Manual/Chapter 4/2013/2

Diagram 501 may be used only in combination with a supplementary plate to diagram 502 or 503. The supplementary plates may not be used alone. The distance may be varied (see Appendix C). A supplementary plate to diagram 608 (Dual carriageway) may be used in addition to a plate to diagram 502 or 503
2.1 The sign to diagram 501, together with a plate to diagram 502 or 503 showing the appropriate distance, should be used where the clear visibility GIVE WAY sign is less than the distance given in table 2-1. The sign may also be accompanied by the word SLOW (diagram 1024) marked on the carriageway. Where the Junction is With a dual carriageway road, a plate to diagram 608 may be added below the STOP or GIVE WAY plate (see also paras 5.15 to 5.17). Where there is a gap in the central reservation 502 Distance to a STOP line and a right turn is permitted, this should reduce the risk of drivers turning into the wrong carriageway. See Chapter 3 for further guidance on the STOP and GIVE WAY signs, and Chapter 5 for road markings at distance (see paras 1.22 and 1.23) to the STOP or junctions.
Table 2-1 Advance warning sign criteria, sizes and siting :
| 85th percentile speed | Clear visibility distance below which an advance warning sign should be provided | Size of advance warning sign (see note 1) | Size of advance warning sign (see note 1) | Supplementary plate x-height (see note 1) | Supplementary plate x-height (see note 1) | Distance of advance warning sign from STOP or GIVE WAY line (see notes 2 and 3) |
| (mph) | (m) | (mm) | (mm) | (mm) | (mm) | (m) |
| Up to 30 | 45 | 600 | | 62.5 | | 45 |
| 31 to 40 | 60 | 750 | (600) | 75.0 | (62.5) | 45–110 |
| 41 to 50 | 90 (150) | 900 | (750) | 100.0 | (75) | 110-180 |
| Over 50 | 150 | 1200 | (900) | 125.0 | (100) | 180-245 |
| NOTES Alternative sign sizes are shown in brackets. As these are safety-critical signs warning of a requirement to give way or stop, the smaller alternative should be used only where physical constraints make this necessary or, exceptionally, where special amenity considerations apply. A larger size than recommended may be used where the accident record justifies greater emphasis, as may the greater clear visibility distance in column. The size of the supplementary plate is matched to the corresponding sign, e.g. 62.5 mm with 600mm, 100 mm with 900 mm. The 50 mm size plate to diagram 608 is not used with this sign. Reference should be made to Note 5 in Appendix A for more specific guidance on siting distance. The distance shown on the supplementary plate must always be in yards, to the nearest 10 yards. Metres must not be used. |||||||
These signs may be used with diagram 511 or 572. Diagram 506.1 may additionally be used with 7301 "WORKS ACCESS" or 7302 “WORKS EXIT”. For permitted variants see para 2.3
PRIORITY JUNCTIONS
2.2 Signs to diagrams 504.1 to 507.1 indicate the presence of a junction. The priority route is indicated by the thicker route symbol. This may not necessarily be a route of the same status or with the same route number. The signs may be used only on the priority route, i.e. the width of the part of the symbol indicating the approach arm must not be varied. Diagram 505.1 must not be used on an approach that does not have priority at the junction. Where advance warning of the junction is considered necessary on the non-priority approach, diagram 501 with the appropriate distance plate should be used.
2.3 Diagrams 505.1, 506.1 and 507.1 may be reversed. Diagrams 504.1, 506.1 and 507.1 may be varied so that the thicker symbol indicates the priority route, except that in diagrams 504.1 and 507.1 the thicker symbol must not indicate that a priority route is crossing ahead; the STOP or GIVE WAY sign to diagram 601.1 or 602 should be used in these circumstances. Details of the variants are shown on the working drawings (see para 1.8). No other modifications are permitted.
2.4 The sign to diagram 507.1 should be used only in the following circumstances:
(i) where the 85th percentile speed of traffic is 30 mph or less and the stagger does not exceed 50 m, or
(ii) where the 85th percentile speed of traffic is greater than 30 mph and the stagger does not exceed 120m.
2.5 If the priority route is itself the staggered route through the junction, diagram 507.1 must not be used, but a map-type advance direction sign might be beneficial. In all other cases, the two junctions should be signed individually with signs to diagram 506.1.
A supplementary distance plate to diagram 572 (see section 18) should be provided at the second sign in cases where the siting distance shown in column 4 of the table in Appendix A is greater than the distance between the two junctions.
2.6 Warning signs should not generally be used where the indication of a junction is given by a map-type advance direction sign. Nor is a warning sign normally required when a stack-type advance direction sign is used, except where the layout will not otherwise be apparent, eg at a staggered ​crossroads Signs are required at junctions controlled by traffic signals only in the circumstances described in para 8.3. Exceptionally, warning signs may be provided in addition to advance direction signs where visibility is so poor that drivers are unable to obtain an adequate advance view of the junction or the directional signs associated with it.
2.7 Junction warning signs are not normally provided on very minor rural roads, nor in urban areas where it would be impracticable to sign every junction. They may of course be used where a specific need has been identified.
TRAFFIC MERGE
2.8 A sign to diagram 508.1 or 509.1 is used to give warning where two physically separated streams of traffic proceeding in the same direction join the same carriageway. These signs may be used only in situations where the traffic stream joining from a These signs may be used only in conjunction with diagram 7070 and may be used with diagram 572 slip road crosses a road marking to diagram 1010 (direction 17) and is required to concede priority to any through traffic. They are not intended for use at lane gain junctions where one or more traffic lanes are added to the main carriageway. Diagrams 868, 868.1 and 873 to 876 may be used in these circumstances.
2.9 The sign to diagram 508.1 is used to warn that there is traffic joining on the left hand side and should be sited on the left of the main carriageway. The sign to diagram 509.1 is used to warn drivers that they are about to join a main carriageway and may have to concede priority. Neither sign is reversible. The designs prescribed in the 1964, 1975 and 1981 Regulations (diagrams 508 and 509) where both arms of the symbol have equal weight, were required by the 1994 Regulations to be removed by 31 December 1998 and are now therefore unlawful.
2.10 Traffic merge warning signs should normally be used only in the following circumstances:
(i) where there is no other advance signing on a main carriageway indicating a junction ahead, e.g. where there is an access slip road, but no exit slip road preceding it to alert drivers to the likelihood of joining traffic, or
(ii) where there is a series of closely-spaced junctions which are a mixture of lane gain and lane merge (but see para 2.11), or
(iii) where it is not apparent to drivers that they are on a slip road (e.g. a former main road through a village joining a by-pass, or the main carriageway of a motorway joining another motorway).
11 Rectangular merge signs based on the lane gain signs referred to in para 2.8 are available on special authorisation (see para 1.5). These may be more appropriate in the circumstance described in para 2.10(ii). Further guidance on the use of these signs will be given in Chapter 2.
2.12 A plate to diagram 572 should be used when the distance between the sign and the merge point is different from that recommended in Appendix A (but see para 1.20).
May be used with diagram 57 7, 573.7 or 572
May be used only in combination with diagram 504.7, 505.7, 506.7, 507.7, 570, 572, 572.7, 572.2, 573, 576, 577, 520, 523.7, 524.7, 528 or 556
A distance in yards to the nearest 70 yards may be added before, or substituted for the word "AHEAD"
ROUNDABOUTS
2.13 The sign to diagram 510 may be used to indicate the approach to a roundabout where adequate warning is not conveyed by a map-type advance direction sign. It may be used with a supplementary plate to diagram 511, 513.1 or 572. The roundabout warning sign should be used only for true roundabouts. It should not be used to give advance warning of a gyratory system or where the approach to an otherwise standard roundabout is controlled by signals (see paras 8.4 and 8.5).
2.14 On high standard all-purpose dual carriageway roads subject to a speed limit of 70 mph, diagram 510 should be used in addition to the map-type advance direction sign and be supplemented by a plate to diagram 511 "REDUCE SPEED NOW". One sign and plate should be situated on the central reservation 500m in advance of the roundabout, with a duplicate on the left side 450 m in advance (see also paras 5.7 and 5.13).
2.15 Where a roundabout on such a road follows a series of grade separated junctions, the signing described in para 2.14 should be supplemented by an additional sign to diagram 510 on each side of the carriageway, plated with diagram 572 "½ mile". On other roads, where accidents result from excessive approach speeds, signs to diagram 510 should be sited in accordance with the recommendations in Appendix A.
2.16 At mini-roundabouts, a roundabout warning sign should be provided if the clear visibility distance (see para 1.23) of the sign to diagram 611.1 is less than indicated in the relevant sections of table 2-1 and the junction is not preceded by an advance direction sign to diagrams 2024, 2119 or 2120 depicting the roundabout.
2.17 The "REDUCE SPEED NOW" plate may be used with the diagrams detailed, where it is considered that a warning sign alone might not result in a sufficient reduction of speed to enable the hazard to be negotiated in safety.
2.18 Where further emphasis is needed on high-speed approaches on dual carriageway roads, the countdown markers to diagrams 823, 824 and 825 may be used, sited 300, 200 and 100 yards respectively from the give way line. The background colour must be changed to green when used on a primary route, and white (with black symbols and border) on a non-primary route. The signs should normally be mounted in pairs on each side of the carriageway, with the signs on the central reservation being reversed so that the bars incline downwards to the left.
2.19 The sign to diagram 7014 with the legend "NEW ROUNDABOUT AHEAD" (see para 1.17 for guidance on size) may be erected to warn of a new roundabout. Its use is restricted to a period of not more than 3 months from completion of the works (direction 37), after which it must be removed.