Development of a performance based specification for roadmarking

The Transit New Zealand Authority has approved a policy objective to move to performance based specifications whenever possible. It is believed that performance based specifications will provide an environment which encourages innovation and risk sharing. This paper describes progress to date in preparing a performance based specification for roadmarkings in New Zealand, the need for such a specification, some of the implementation issues, and provides an outline of the specification developed to date. The conceptual framework of a performance based specification is that there are key properties of a product such as a roadmarking which determine whether it can fulfil its function. Preferably these properties can be measured directly on the road. Where this is not possible, either the property is measured indirectly in situ or is inferred by a laboratory based measurement. Preparation of a performance based specification required a reappraisal of the properties required of roadmarkings for them to achieve their function so that only the key properties would be specified. This review was undertaken with input from a discussion group involving members of the industry drawn from roading authorities, materials suppliers, marking contractors, and research and testing laboratories. The paper discusses how the properties identified could be measured including limitations of the equipment and minimum required values. The need for these properties to be maintained for a minimum durability period, and the need for this minimum period to increase for high traffic volumes, is also discussed. Issues such as residual life, testing regimes, length of contract period, and implementation needs are also considered.