Highways Agency - Safe roads, Reliable journeys, Informed travellers

13. Appendix D - Assessment of Condition of Traffic Signs

D.1 Introduction

It is important that all items of equipment used for temporary traffic management fulfil their intended legal and informative function throughout the period they are in position. This applies to all signs, delineators, markings, traffic signal equipment and road danger lamps. For instance, with age the retro-reflective properties of signs degrade and the sign face colours will also fade. Even in normal use, temporary traffic management signs and delineators are subject to forms of damage not experienced by permanent signs. This damage occurs during storage, delivery, installation, and removal, causing deterioration in appearance and effectiveness.

However, it is not practical to specify new signs and delineators for each project. Therefore guidance is needed to facilitate the assessment of the condition of temporary traffic management equipment. To help to achieve this objective illustrations of appropriate sign samples are included in Section D.4.

Signs with defects which affect recognition and legibility are unacceptable. Temporary traffic management equipment which appears acceptable in good weather conditions, may at other times, for example in heavy rain, not be adequate and so present a potential safety hazard. Such factors should be taken into account when assessing their condition.

Assessment of the condition of equipment should be made at several stages: prior to storage, during assembly for delivery to site, and at regular intervals throughout deployment. In many works contracts, this inspection and assessment is mandatory when the equipment is erected and while it is deployed.

D.2 Condition Classification

The condition of each item of temporary traffic management equipment should be classified as follows:

• acceptable
• marginal
• unacceptable

Acceptable

Equipment which falls within this classification is appropriate for initial deployment and continued deployment on the highway. At the time of the initial set up all equipment shall be in the "acceptable" category.

Marginal

Equipment which falls within this classification is reaching the lower end of acceptability and should not be delivered to site. During a project, following an assessment of condition any equipment classified as "marginal",

a) should be replaced within 24 hours if it is not repeated

b) if the item is repeated, it may remain in place until:

- it is assessed as unacceptable, or

- marginal items exceed 20 percent of the group (eg a set of repeater signs), or

- marginal items exceed 1 in 5 consecutive pieces of equipment (eg traffic cones).

Unacceptable

Devices in this category shall not be delivered to the site. When found in use, they should be replaced immediately.

D.3 Condition Assessment

Illustrations and associated descriptions, are provided in Section D.4 to assist assessment of condition of signs and delineators.

Temporary traffic management equipment inevitably becomes dirty during use and consequently becomes less conspicuous and legible, particularly at night and in adverse weather conditions. Thus regular cleaning is essential.

All items of temporary traffic management equipment should be cleaned prior to assessment of their condition and regularly cleaned throughout their time on site.

D.3.1 Signs and delineators

Signs and delineators should be assessed in relation to the following properties.

• Structural integrity
• Sign face condition
• Sign face colour
• Level of retro-reflectivity

A sign or delineator assessed as failing in any one of the above categories should be classified as unacceptable.

A sign or delineator assessed as marginal in any one of the above categories, but passing in the others should be classified as marginal.

A sign or delineator assessed as marginal in two or more categories should be classified as unacceptable.

Signs of a suitable size with defects which affect recognition and legibility should be classed as unacceptable.

Signs which are not mounted at the specified height should be classed as unacceptable.

The practice of mounting signs on unnecessarily long posts which project above the top of the sign is hazardous and unacceptable.

Any sign or delineator which does not conform in every detail with the requirements in the Traffic Signs Regulations and General Directions is unacceptable regardless of its condition.

Structural Integrity

Sign plates should be checked to ensure that they are adequately fixed to their frames. Where a frame, including A-frames, is broken or deformed so that the sign cannot be adequately secured or the sign plate is not at the appropriate angle to the road surface, it should be classified as unacceptable.

Sign Face Condition

Legibility can be affected by scratches and other damage to the sign face. This can be best assessed at the appropriate viewing distance. The severity, extent and location of such damage must be taken into account when deciding whether a sign should be classified as unacceptable. For example a relatively small area of damage could render a letter illegible and seriously compromise drivers' ability to comprehend a sign, see Section D.4 for illustrated examples.

Sign Face Colour

If colour fading is noticeable it should be visually compared with a square of new/perfect material. For regulatory signs such as speed limit signs, any significant colour fading may compromise regulatory enforcement, and is therefore unacceptable. For information signs, legibility and vivid colour contrasts should be the main criteria.

Level of Retro-reflectivity

Delineators should be highly conspicuous and all signs, symbols, and letters should be clearly visible during darkness. The retro-reflective properties of signs and delineators can be assessed, whilst they are suitably illuminated, by visual comparison with a new/perfect sample of retro-reflective material. Alternatively the retro-reflectivity properties of signs and delineators can be assessed using a Field Retro-reflectometer and readings can be directly compared with BS 873 Part 6 Table 1. However, the use of a Field Retro-reflectometer should normally only be required in special situations or where the results of other methods are disputed.

Retro-reflectivity can be significantly reduced by dew formation on the sign face, and assessments should not take place in such circumstances.

D.3.2 Road Danger Lamps

All lamps must be working and in good condition.

D.3.3 Traffic Signal Equipment

Faulty equipment must not be placed on a public highway. All traffic signal equipment should be inspected and tested before delivery to the site. Information on fault detection procedures is given in Chapter 8 of the Traffic Signs Manual. Useful advice is contained in 'An Introduction to the use of vehicle actuated portable traffic lights'.

D.3.4 Temporary Road Markings

All temporary road markings such as studs, paint and tape must be installed according to the manufacturer's instructions, and their performance regularly monitored throughout the project.

D.4 Sign Condition Assessment Guide

This Section contains colour illustrations and associated descriptions to assist assessment of signs and delineators.

• D.4 Sign Condition Assessment Guide (649KB PDF).