replaced by the warning line (see paras 4.12 to 4.26) where appropriate. When there are two or more lanes in each direction, consideration might be given to double white lines (see section 5).
4.4 Where forward visibility is restricted (see para #4.16) or on the approach to some other hazard (e.g. a roundabout or other junction), the centre line marking should be replaced with warning lines to diagrams 1004 or 1004.1 (see figure 4-3). These are the inverse of the mark/ gap dimensions for the centre line and therefore maintain the same module (see table 4-3 for the minimum number of marks).
4.5 On two or four lane roads the marking should normally be laid in the geometric centre. It can however be laid off-centre to allow parking along one side. Where it is necessary to change the position of lines in relation to the centre of the road, the deflection should be smooth and made at the inclinations specified in table 14-1.
4.6 On rural roads below 5.5 m in width, over-running of the carriageway edge can occur if centreline markings are provided, causing maintenance problems. Drivers might also expect a road marked with a centre line to be wide enough for opposing lanes of traffic to pass. In these circumstances the centre line should be omitted, but it would be helpful if edge of carriageway markings are then used.
LANE LINES
4.7 Lane lines (see figure 4-2) ensure that available carriageway space is used to its maximum capacity. In-helping vehicles to maintain a consistent lateral position, they also offer safety benefits and should be used wherever practicable.
| Diagram No. |
Speed limit (mph) |
Mark (m) |
Gap (m) |
Width (mm) |
Spacing of studs (if used) (m) |
|---|---|---|---|---|---|
| 1005 | 40 or less | 1 | 5 | 100 (150) | 12 |
| 1005.1 | Over 40 | 2 | 7 | 100 (150) | 18 |
4.8 The marking is intended for dividing the carriageway into lanes where traffic on either side of the line travels in the same direction, and not for separating opposing flows of traffic. Details are set out in table 4-2.
4.9 Lane lines on the approach to Give Way and Stop markings, including roundabouts and traffic signals, should change to warning lines in accordance with table 4-3 and para 4.24.
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