Page:UK Traffic Signs Manual - Chapter 8 - Part 1 (Traffic Safety Measures and Signs for Road). Designs 2009.pdf/28

 The location of tapers should be decided following a risk assessment but, in general, on dual carriageway roads tapers should not be installed adjacent to entry or exit slip roads.

It is essential, before detailing tapers as part of the traffic management design, that a full appreciation of the site is obtained, a site visit is the only way to be sure that the theoretical layout can be achieved in practice. Consideration of safety issues involved in placing, erecting and removing advance warning signs and cones in the taper and the provision of safe pulling off points for traffic management vehicles may also be factors in deciding the taper position.

In addition, on roads without hard shoulders, the traffic management should be designed so that safe taper positions are identified which facilitate the provision of advance signing without the need for stationary or slow-moving works vehicles to encroach into live lanes when pre-placing, erecting or removing traffic management equipment.

Where road works are situated near a bend in the road, and especially a left-hand bend, it is essential that adequate advance warning is given to approaching drivers because of the reduced visibility. An indication should be given of the path that must be followed to avoid any obstruction in the carriageway.

Works should be designed to minimise the risks to road users and the workforce. Having done so, implementation of a temporary mandatory speed limit should be considered, especially where the workforce is required to operate on the carriageway, or other vulnerable area.

There may often be pressure for temporary speed limits, but it is important that their limitations as a protection to persons working on the site should be realised. Traffic speeds will inevitably be reduced where busy roads are severely obstructed, so a speed restriction may not be necessary. On dual carriageway roads, where works requiring protection are taking place within the central reservation or on the other carriageway, any protection necessary on the unobstructed carriageway should be given by means of coning rather than a speed limit.

To help ensure compliance, the designer should involve enforcement agencies early in the design of a road works scheme to ensure agreement on enforcement issues and the siting of cameras and signs. The locations of cameras, either at a fixed point or for average speed measurements, should be designed to reduce the likelihood of drivers making sharp braking manoeuvres. It is, therefore, recommended that cameras are not located between the initial terminal speed limit signing and the first repeater sign, see Table 3.4, Note 1. The design programme for such works should make provision for the time necessary to obtain temporary traffic regulation orders.

In the event of an emergency, when road users or road workers are at risk and there is insufficient time to obtain temporary traffic regulation orders under normal procurement procedures, consideration should be given to obtaining a traffic order under emergency notice procedures (section 14(2) of the Road Traffic Regulation Act 1984).

Where it is impracticable to obtain a mandatory speed limit, consideration should be given to the application of an advisory speed using the bottom panel to diagram 7275 or the free-standing sign to diagram 7294. VMS or matrix signals may also be used to show the maximum speed advised. The method for assessing the appropriate speed is the same for advisory speeds as for mandatory speed limits.

For roads other than motorways where the highway width is so restricted as to prohibit the provision of the appropriate lateral safety clearance, one option is to reduce traffic speeds to less than 10 mph and an agreed safe method of working imposed on the site, see Section D7, Convoy Working. This may be achieved by 27