.svg)
Figure 14-16 Example of a signalled junction with three different speed limits (see para 14.18)
| Type of approach road | Speed limit on approach road (mph) (higher limit) | ||||
|---|---|---|---|---|---|
| 30 | 40 | 50 | 60 | 70 | |
| Size of sign (mm) | |||||
| Single carriageway or one-way road | 600 | 600 | 600 | 750 (600) | – |
| Wide single carriageway (10 m or more) | – | 600 | 750 | 900 (750) | – |
| Dual carriageway | – | 750 (600) | 900 (750) | 900 | 1200 (900) |
| Motorway | – | – | 1200 | 1200 | 1200 |
NOTE 1: The smaller alternative sizes shown in brackets may be used where the 85th percentile speed on the approach road is at least 10 mph less than the legal speed limit on that road or where a narrow central reservation or similar constraint makes the larger size impracticable.
NOTE 2: Where the terminal sign indicates a higher speed limit, this should generally be the 600 mm size, except that a 750 mm sign should be used on dual carriageway roads where the lower approach speed limit is 50 or 60mph.
NOTE 3: Where signs of different diameters are to be mounted back to back (and a backing board is not used), consideration should be given to using the larger diameter for both, as this should result in a neater and less cluttered assembly.
NOTE 4: See table 14-2 (Note 3) for use of the prescribed size of 450 mm as a terminal sign. The prescribed 300 mm sign is used only for repeater signs (see table 14-4) and never as a terminal sign. The prescribed 1500 mm sign is for use only at road works (see Chapter 8, Part1).
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