Federal Highway Research Institute

Reference section for measuring systems to monitor the texture of road surfaces

The texture of a road surface represents a link between all functional features, and is a decisive factor that simultaneously influences road safety and the emission of noise and CO2.

The picture shows a diamond ground texture of a concrete pavement

Background

The texture of a road is a primary factor that influences the most important functional features of road surfaces: skid resistance, rolling resistance and tyre noise. A distinction is made between micro, macro and megatexture. The microtexture when combined with the macrotexture has a major impact on skid resistance on damp roads. The macrotexture also influences the rolling resistance and noise emissions of a road. The megatexture, by contrast, determines the comfort for travellers and the forces exerted on the transported load. The texture therefore represents a link between all functional features, and is a decisive factor that simultaneously influences road safety and the emission of noise and CO2.

The texture measurement is based on various measuring principles. Currently their comparability and an ISO-compliant suitability test are only possible to a limited extent.

Concept

To check the suitability of the texture measuring systems, a reference section with defined surface textures and different degrees of surface roughness has been constructed in the northern part of the duraBASt. Special extremely precise calibration surfaces made of coated stainless steel with a triangular, rectangular and trapezoidal profile shape additionally serve as test equipment, on the basis of which it is possible to test the measurement accuracy and linearity of the optical texture measurement surfaces.

Objectives

The picture shows a texture measuring device on a road T3Dk, BASt’s stationary texture measuring device

Integrated surface textures and the test equipment facilitate an ISO-compliant inspection of the optical sensors on fast moving and stationary texture measuring systems.

Furthermore, the reference textures will be used when further developing the measurement technology and for analysing the correlations between the road surface characteristics (skid resistance, rolling resistance, tyre noise) and the texture.

In the long term, the section will also be used to integrate the fast moving and contactless recording of texture into the ZEB (road monitoring and assessment).