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Base works for the updating of the standards about visual monitoring of the pavement surface (VSS2010/701)

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Complete with results
Geo-spatial type
Project website
STRIA Roadmaps
Infrastructure (INF)
Transport mode
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Transport sectors
Passenger transport,
Freight transport


Background & Policy context

Visual surveys and evaluations of surface damage are necessary components of the road maintenance management process. The results of such evaluations define the priority of possible maintenance sections. This methodology is used actively within the federal administration as well as in the cantons and cities. The experiences of users, however, shows that the standard SN 640 925 should be updated.

Today's standard includes 22 characteristics for visual surveying. The distinction of these many characteristics leads often to difficulties in the evaluation. These characteristics are to be examined therefore and so specified, to be really helpful for the choice and evaluation of maintenance works. The different needs of the different user groups are if necessary to be graded into different evaluation processes.


The project has following objectives:

  • Simplification of the existing method of the visual diagnostic and condition evaluation
  • Compilation of a basis, which ensures the today's requirements and the won experiences to be considered in practice and let further treatment in accordance with the PMS process
  • Determination of the procedure, with consideration of different user groups
  • Examination of the procedure and methodology in other countries
  • Examination of different existing surveying methods
  • Consideration of the past experiences in the administrations
  • Development of bases and proposals for the updating of the existing standards
  • New grouping of the characteristics due to their homogeneity for maintenance planning (characteristics, which cause the same action, are to be summarised in the same group)

Guarantee of the continuity in the used procedures of surveying evaluation by creation of suitable correlations for the future usability of the existing results from earlier evaluation


The research methodology is divided into four phases. As part of Phase 1, together with the literature study carried out a survey of users with an analysis of the results of the survey and the consequent draw conclusions. In phase 2, the necessary under circumstances distinctions for network-dependent data collection and assessment methods are defined and justified. The Phase 3 issued an methodology for certain user categories. In phase 4, a final report with a proposal for specific application as well as a draft standard to be created.

In this research, therefore, the procedure is as follows:

  • Determination of status features for qualitative and quantitative representation of a state taking into account the conversion of the values in an action planning.
  • Development and demonstration of the procedure for determining state values for various levels (federal, cantonal, cities and municipalities, differentiated by high-performance roads, main roads, connecting roads, collection and access roads)
  • Recommendation of state areas for various levels and types of roads for minimal and optimal maintenance strategies (state areas: "good", "medium", "adequate", "critical" and "bad").
  • Development of a revised, standardised condition assessment, which takes into account the recent admissions process and future developments.
  • Working out of bases (draft standard) to revise and supplement the standards 640 925b, 925b Appendix 640 and 640. 926



Parent Programmes
Institution Type
Public institution
Institution Name
Swiss Government: State Secretariat for Education and Research
Type of funding
Public (national/regional/local)
Funding Source
144'800.00 CHF


The research provides the foundation that allows the person in charge of road equipment, perform efficient visual survey of the surface state due to the latest findings in order to cover an important part in conservation management. It ensures a supported on the different needs of communities, cantons and the federal government method for visual determination and assessment of the surface condition to apply.

The revised standard takes into account the current state of knowledge in conservation management and thus forms for the user in municipalities, cantons and the federal government and the planners and engineers commissioned an important and necessary part of the implementation of targeted conservation management of road systems.


Lead Organisation
EU Contribution
Partner Organisations
EU Contribution


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