Page:UK Traffic Signs Manual - Chapter 4 - Warning Signs. 2013.pdf/11

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2JUNCTIONS

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)		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)		(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.

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