The existing traction standards SN 640 510 (measuring method) and SN 640 511 (assessment) have been published in their current form in 1985 and 1984. They have not been updated for almost 20 years.
The standard 640 510 (measuring method) takes account of the "combined grip and texture measurement" with the English SRT pendulum and discharge meter after Moore and on the other hand, the process with the blocked idler "skiddometer". Other measuring methods and instruments, in particular the modern high-performance systems for state detection at the network level (SRM, Scrim) are not included in the standard.
The current SN 640 511 (assessment) contains only a guideline for the respective measurement speed but neither an assessment nor a scale approach to below the guideline value.
The future standard series must provide a clear assessment approach and better application in practice.
The project has following objectives:
- Providing of a base work for updating of the Swiss standards for skid resistance
- Collecting the newest knowledge about traffic security and skid resistance
- To se different measuring methods (skiddometer, SCRIM, SRM) according the Swiss standard
- To define practicable standards for the analysis and evaluation of skid resistance measurements
The expected results are:
- Current bases for standard revision
- Supplemented static and dynamic methods of measurement
- Amended and new assessment procedures
- A practical assessment methodology for grip terms
Traffic safety and quality newly built coverings (decrease).
- Formulation of possible further normalisation and / or research needs.
For this research the following procedure is provided:
- Study of literature (especially the foreign measurement and assessment methods).
- Analysis and comparison of existing SN and EN standards for grip.
- Assessment and weighting of the findings of the analysed literature and the experience of practice in Switzerland.
- Derivation of evaluation and assessment scale grip
- Assessing the road safety issue and establishing a review process.
- Compilation of the bases for the revision of the standard.
The research report consists on the one hand of the actual synthesis report and on the other hand of detailed appendices with all collected information. A substantial part of it consists of the bibliographical evaluation, which discusses and structures all relevant aspects of the examined sources of literature. In addition, for the most important sources of literature, small summaries were compiled. This bibliographical evaluation confirms the enormous variety of the European measuring and evaluation methods, which are contained in numerous national instruction guidelines, standards and recommendations. These documents are naturally only valid for the considered measuring procedures and for the respective evaluation method.
The synthesis report summarises first the technical and physical fundamentals of the texture, the skid resistance and the different pavement grip measuring methods. The various principles of measurement and the families of corresponding devices are then described (detailed data are in the appendices to find). The various methods and scales of evaluation used in Europe are described and analysed. Some of the numerous factors of influence on pavement skid resistance and its temporal evolution are described likewise.
In the final part of the report different recommendations and beginnings for the revision of the Swiss skid resistance standards are given: As acceptance test of the wearing courses a measurement of the macro texture is recommended. Due to the better reliability of this type of device, dynamic skid measurements are to be done preferably with straight led measuring wheel (coefficient of longitudinal friction).