Page:UK Traffic Signs Manual - Chapter 8 - Part 2- Traffic Safety Measures and Signs for Road Works and Temporary Situations) - Operations 2009.pdf/126

MOBILE LANE CLOSURE TECHNIQUE

When a closure is to be removed, either because work is complete or the traffic flows are getting too high (see Section O10.4), the supervisor should instruct the drivers of the working vehicles and the block vehicles to move off the carriageway, on to the hard shoulder if one is available, while the rest of the team maintains station. For a right lane closure this may involve accelerating in the lane occupied and then manoeuvring to the left as gaps in the traffic occur.

Once the lane closure vehicles are off the carriageway, the supervisor should instruct that the vehicles should stop and the signs be covered. Any static signs should be recovered. Drivers can then be instructed to leave the site. From this stage in the procedure drivers should proceed independently and at a normal pace.

Where there is no hard shoulder, as soon as the work has been completed and the block/works vehicles have moved off, the signs on the advance warning vehicles should be covered at their last stationary position clear of live traffic.

If the mobile train is required to move further along the road to commence work elsewhere, the supervisor should direct the drivers accordingly. On roads with a hard shoulder, where traffic flows are light and there is a short distance between works sites (e.g. 2-3 km), the train can be kept together with the closure operational and travelling at 20-25 km/h (12-15 mph) to the next site. Otherwise, the closure should be removed and the signs covered. The drivers should then be instructed to take their vehicles to the next site independently.

As with daytime use, the technique should be employed only in conditions of good visibility; see paragraph O10.1.9. It may be used on both lit and unlit carriageways. Care should be taken when operating this technique near dusk or dawn.

Using the MLC technique at night on roads with no proper hard shoulder can present particular difficulties in safely siting and relocating the advance warning sign vehicles off carriageway. The technique should be used in these circumstances only by very experienced practitioners. The guidance in this document for daytime use on roads with no hard shoulders should be supplemented by a specific risk analysis. A detailed analysis for each case is required. This will need to be preceded by a site inspection carried out by a competent responsible person having relevant MLC experience to determine exactly where sign vehicles can pull off safely without getting bogged down and the findings included in the site specific quality plan and instructions.

Personnel may experience difficulty reading marker posts at night so the fitting of an adjustable spotlight is advised. Before leaving the depot all lighting equipment should be checked.

A relief driver may travel in the working vehicle to give directions during complicated manoeuvres and to replace any other driver in the train, if required. This is especially important at night as the additional stress can bring on premature fatigue. See paragraph O10.3.7.

The plans and principles for the operation of the MLC technique are given in Plans MLC1 to MLC7. They relate to the free-flowing conditions found on motorways and other dual carriageway roads with gradeseparated junctions. The separation distance between block/working vehicles is a compromise between the need to keep the gap small to discourage other vehicles from breaching the closure and allowing sufficient room to avoid the block vehicle being pushed forward into the working vehicle should it be struck from behind. The block vehicle shown in the plans has the same specification as an Impact Protection Vehicle; see paragraph O5.5.5. 124