Traffic Signs Manual/Chapter 5/2009/11

11YELLOW BAR MARKINGS

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11.1 Yellow bar markings are used in certain conditions on high speed approaches to roundabouts, either on the main carriageway or on an exit slip road. They have been shown to be effective in reducing accidents associated with speed adaptation, i.e. where drivers have been travelling at sustained high speed for long periods. The types of accidents most likely to be influenced are single vehicle and overrun accidents. The markings should not be used in an attempt to reduce speeds at sharp bends or other hazards. They are not normally appropriate on slip roads if there is a segregated left turn lane for the roundabout, or at roundabouts controlled by traffic signals. On approaching a green signal, some drivers will slow down in response to the markings, others will maintain speed in an attempt to beat a change to red. Markings are unlikely to be approved in such cases unless the accident justification is strong.

11.2 Before use of the markings is contemplated, it is essential to ensure that all standard signing has been correctly installed. The warning signs described in Chapter 4 (paras 2.13 to 2.18) should be provided and be of the appropriate sizes. All signs should be checked to ensure they are in good condition and not obscured e.g. by vegetation, and sited at the correct distances from the junction. Only then should treatment with yellow bar markings be considered.

11.3 The markings are not prescribed in the Traffic Signs Regulations and General Directions 2002. However, for installations in Northern Ireland, where they are prescribed for use at roundabouts on dual carriageway roads only, reference should be made to Appendix A. Elsewhere, written authorisation from the Secretary of State will need to be obtained for each site where it is proposed to use them (see para 2.1). Authorisation will normally be given only where the following criteria are met:

(i)the carriageway on which they are to be laid is a one-way approach to a roundabout (i.e. a dual carriageway or an exit slip road),

(ii) there is at least 3 km of dual carriageway in advance of the site, with no major intersections or bends with a horizontal radius less than the desirable minimum for a 120 kph design speed shown in table 3 of TD 9 / 93 in Volume 6 of the Design Manual for Roads and Bridges (see para 1.4),

(iii) the road is subject to the national speed limit of 70 mph, and

(iv) the accident record for the roundabout includes at least three accidents involving personal injury during the preceding three years, in which speed on the relevant approach was a contributory factor.

11.4 Each approach to a given roundabout is treated as a separate site and the use of the markings on each approach must be justified independently. The application of the criteria in para 11.3 will ensure that the markings are used only at sites where they are likely to make a positive contribution to safety.

11.5 The marking consists of 90 yellow transverse bars on main carriageways, and 45 on slip roads. The bars are 600 mm wide, and are laid at right angles to the centre line of the carriageway (see figure 11-1 for details of the layout on a main carriageway). The first bar is laid at a distance of 50 m measured along the centre line of the carriageway in advance of the Give Way line. Successive bars are spaced in accordance with the running measurements in table 11-1 for main carriageways and in table 11-2 for slip roads.

11.6 To assist surface water drainage, each end of each bar should be terminated about 150 mm from the edge of the carriageway or the edge line marking if provided. This may be increased to 750 mm where there is a particular drainage problem, or if there are significant numbers of cyclists. Bars should not be extended across hard strips or hard shoulders as this would give the impression that these are traffic lanes.

11.7 Skid resistance of the bars should not be less than 55. Drop-on glass beads should not be applied. The bars should not exceed 5 mm in thickness, and the combined thickness of the bars and any superimposed marking must not exceed 6 mm. Although thinner markings might need more frequent renewal, they are less likely to result in noise levels which are unacceptable to local residents.

Table 11-1 Spacing of bars on main carriageway

Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)
D1	0.00	D21	60.10	D41	133.75	D61	224.70	D81	338.15
D2	2.75	D22	63.45	D42	137.85	D62	229.80	D82	344.65
D3	5.50	D23	66.80	D43	142.00	D63	234.90	D83	351.35
D4	8.25	D24	70.15	D44	146.15	D64	240.10	D84	358.30
D5	11.05	D25	73.60	D45	150.40	D65	245.40	D85	365.50
D6	13.90	D26	77.05	D46	154.65	D66	250.70	D86	373.20
D7	16.80	D27	80.55	D47	158.95	D67	256.10	D87	380.90
D8	19.70	D28	84.10	D48	163.35	D68	261.50	D88	388.60
D9	22.60	D29	87.65	D49	167.75	D69	267.00	D89	396.25
D10	25.55	D30	91.30	D50	172.25	D70	272.60	D90	403.95
D11	28.55	D31	94.95	D51	176.75	D71	278.20
D12	31.60	D32	98.65	D52	181.30	D72	283.90
D13	34.65	D33	102.40	D53	185.95	D73	289.60
D14	37.70	D34	106.15	D54	190.60	D74	295.45
D15	40.80	D35	110.00	D55	195.35	D75	301.30
D16	43.95	D36	113.85	D56	200.10	D76	307.25
D17	47.15	D37	117.75	D57	204.90	D77	313.30
D18	50.35	D38	121.70	D58	209.80	D78	319.35
D19	53.55	D39	125.65	D59	214.70	D79	325.55
D20	56.80	D40	129.70	D60	219.70	D80	331.75

Table 11-2 Spacing of bars on slip roads

Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)	Bar No.	Distance from D1 (m)
D1	0.00	D11	30.20	D21	67.20	D31	112.90	D41	170.00
D2	2.75	D12	33.55	D22	71.35	D32	118.00	D42	176.70
D3	5.55	D13	37.00	D23	75.60	D33	123.30	D43	183.90
D4	8.45	D14	40.50	D24	79.90	D34	128.70	D44	191.60
D5	11.35	D15	44.05	D25	84.30	D35	134.20	D45	199.30
D6	14.35	D16	47.70	D26	88.80	D36	139.80
D7	17.40	D17	51.45	D27	93.45	D37	145.50
D8	20.50	D18	55.30	D28	98.20	D38	151.35
D9	23.70	D19	59.20	D29	103.00	D39	157.40
D10	26.90	D20	63.15	D30	107.90	D40	163.60

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.)

This is NOT an official transcription, and should NOT be considered in any way a controlled copy of the work in question.

This document no longer necessarily represents current practice, as it relates to an earlier version of the regulations (TSGRD 2002 as amended at publication date) rather than the current TSRGD 2016 regulations. It should not be used for actual design or operational use without consulting a more recent edition.

This version was transcribed in May 2015, from a 2009 impression.