Page:UK Traffic Signs Manual - Chapter 5 Road Markings. 2003 (Sixth Impression 2009).pdf/144



Road marking materials and road studs are specified in the appropriate British Standards. These are generally the English language versions of standards published by the European Committee for Standardisation (CEN).

Road markings are applied using thermoplastic, cold plastic, preformed material or paint. They may be laid as permanent markings or as temporary markings at road works.

Thermoplastic material is applied hot and sets on laying. It may be applied by a hand or mechanical applicator. It has good durability and is suitable for use on all roads. Mechanical application is most suitable for use on motorways and other high standard roads where it can be laid in long runs using motorised equipment with minimum disruption to traffic.

Cold plastics are supplied in single or multicomponent forms. The product is laid on the carriageway and a cohesive film is formed by chemical action.

Preformed thermoplastic road markings are applied by heating the material until it bonds to the road surface by melting or fusion. They provide a simple way to apply arrows, lettering etc. and to reinstate short lengths of line without the need for substantial application and support equipment.

Preformed cold plastic material is applied to the road surface using an adhesive.

Preformed tape is produced in sheet or roll form and is either bonded to the road surface or inlaid. Pressure is applied, but not heat. Preformed markings have good durability, are of uniform thickness and do not spread in hot weather or under the weight of heavy traffic. They can be difficult to apply to some surface dressings and block paviors. They are also manufactured in an easily removable form for use at road works.

Paint is best restricted to roads where the markings are not subject to heavy traffic wear. It is particularly suitable for edge lining, for yellow waiting restriction lines and for parking bays as, being thinner than thermoplastic material, it will not interfere with drainage. The ease and safety in handling paint compared to thermoplastic material, its suitability for laying with motorised equipment and the material's low initial cost, makes paint an attractive economic proposition for such applications.

Initial laboratory requirements for materials are described in BS EN 1790 for preformed markings and BS EN 1871 for directly laid materials. Requirements for drop-on materials (glass beads and anti-skid aggregates) and premix glass beads are dealt with in BS EN 1423 and 1424 respectively. BS EN 1436 specifies several performance levels for properties such as retroreflectivity, skid resistance and durability. Materials will be classified in accordance with the relevant standard following performance testing. In the UK, this will normally be on the basis of laboratory tests to BS EN 1790 or BS EN 1871 as appropriate, and road trials to BS EN 1824.

The Specification for Highway Works published by the Stationery Office specifies which performance classes in BS EN 1436 for luminance factor, skid resistance and retroreflectivity are to be used on trunk roads and motorways. As higher retroreflective performance requires additional glass beads, which will reduce the skid resistance, it is not practicable to specify the highest performance class for both. A judgement will need to be made as to which property is more important at any particular location.

Initial performance requirements for road studs are described in BS EN 1463-1 and the specification for road trials in BS EN 1463-2. The performance levels and classes are listed in BS EN 1463-1. Minimum performance levels to be achieved for use on UK roads are prescribed in the Traffic Signs Regulations and General Directions 2002 (direction 57). Guidance on the correct use of road studs will be found in section 6.