Popis: |
The Swedish National Road Administration's (Vägverket) procurement for road building projects is shifting increasingly towards function-based contracts. This means that the requirements on the evenness of a road surface must reflect the capacity of the surface to serve the road user satisfactorily and with minimal impact on the local environment, while minimising costs for the road authority. In general, there are virtually no evenness indexes describing the serviceability of a road surface in these respects. It is probable that the connection between road evenness and such indexes is of varying strength, which means that the requirements on accuracy in road surface measurement are dependent on the purpose of the measurements. However, earlier research into road user, road authority and environmental effects of road surface characteristics has paid no attention to the issue of what accuracy is required in each case in order to study road surface characteristics and enable the prediction of such effects. Decisions regarding the accuracy required in measuring road profiles demand access to a relatively large sample of realistic road profiles with different evenness levels and spectral composition. Therefore, it was necessary to create a database within the project containing road profiles that had been measured with a known high level of accuracy. Established relations between road evenness and various related factors are largely based on measurements from existing road profilometers of the high-speed type. In order to estimate the value of these relations, it was therefore necessary to investigate whether existing profilometers offer the measuring accuracy required for these purposes. Data obtained from known road profiles with the aid of such equipment were thus collected. |