| Approach road speed limit for private cars (mph) |
Speed limit sign (mph) | ||||
|---|---|---|---|---|---|
| 20 | 30 | 40 | 50 | 60 | |
| Visibility distance of sign (m) | |||||
| 70 | – | 165 | 140 | 110 | 75 |
| 60 | – | 115 | 95 | 65 | – |
| 50 | – | 75 | 50 | – | – |
| 40 | – | 40 | – | – | – |
| 30 | 30 | – | – | – | – |
| NOTE 1: On the side road approach to a priority junction or on any road where the speed limit increases, the visibility distance for each approach speed should be not less than the lowest value shown for that speed (e.g. 50 m for an approach speed limit of 50 mph). Where the approach speed limit is 20 mph, the minimum visibility distance is 20 m.
NOTE 2: Where the 85th percentile speed on the approach road is at least 10 mph less than the legal speed limit on that road, the clear visibility distance may be reduced to that appropriate to the actual speed (e.g. on a country lane subject to the national limit, where the 85th percentile speed is 50 mph the clear visibility distance should not be less than 75 m when approaching a 30 mph speed limit, and not less than 50 m when approaching a 40 mph or 50 mph speed limit). NOTE 3: The minimum clear visibility distance indicated should be provided for both terminal signs. | |||||
REPEATER SIGNS INDICATING MAXIMUM AND NATIONAL SPEED LIMITS
14.21 Where a speed limit other than the national limit is in force, direction 11(2) requires that repeater signs are provided at regular intervals along the road. However, this does not apply to a 30 mph speed limit on a road with a system of carriageway lighting; in built—up areas it would be impracticable to place 30 mph repeater signs on every road. To do so in some cases but not others would result in inconsistency and driver uncertainty. This is therefore prohibited by direction 11(4). Section 82 of the Road Traffic Regulation Act 1984 defines a road that has a system of street lighting (carriageway lighting in Scotland) as being a "restricted road" (see para 14.2). Section 81 specifies that the speed limit along such a road shall always be 30 mph unless an order has been made to impose another limit and remove the restricted road status. The presence of carriageway lighting therefore means that a road automatically has a speed limit of 30 mph with the lamps taking the place of repeater signs. It is therefore of critical importance that, when lit roads have a speed limit other than 30 mph, repeater signs are always provided at the appropriate intervals. Failure to do so undermines confidence in the signing of all speed limits, as drivers have only the repeaters to tell them that the limit is not 30 mph. Where a speed limit, other than 30 mph, applies before and after the point where the street lighting begins, a repeater sign should be located on, or in line with, the first lighting column.
14.22 Where a 30 mph speed limit is imposed on a road without street lighting, it is necessary to make an order. In this case 30 mph repeater signs must be provided (direction 11(2)). Where a road subject to 30 mph limit has street lighting for only part of its length, it is recommended that the first repeater sign for the unlit section when leaving the lit section should be placed at a distance of not more than 100 m from the last street lamp. Where two consecutive street lamps within a system of street lighting are more than 183 m apart (185 m in Scotland) repeater signs should be provided on the section of road between the two lamps. That part of the road must also be covered by a speed limit order as it is not a "restricted road" (see para 14.21).
14.23 A road subject to the national speed limit (see para 14.2) does not require repeater signs except when it has a system of street lighting (direction 11(5)). The purpose of the signs is to remind drivers that the road is not a restricted road with a speed limit of 30 mph. At the point where street lighting commences on a road subject to the national speed limit, the first repeater sign should be placed in line with the first lamp; in most cases the sign would be mounted on the lighting column. This sign should be the appropriate size for a repeater sign (see table 14-4) and not the larger terminal sign. Repeater signs indicating the national speed limit are to diagram 671 and not diagram 670. National speed limit repeater signs are not required on motorways with street lighting (see para 14.27).
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