Measurement vehicles and systems
The following measurement vehicles and systems will be used on the duraBASt test sections.
EFA (detection system for road surface analysis)
The EFA measurement system is a combined “evenness measurement” vehicle that simultaneously measures the longitudinal and transverse evenness on roads. The detection of longitudinal evenness is made using five laser probes in accordance with the HRM principle, with two different measurement base lengths. The transverse evenness is recorded by 41 laser probes at intervals of 0.1 metres. Both recording systems operate on the principle of triangulation.
SKM (sideway-force measurement vehicle)
With the SKM, the sideway force on an artificially-wetted track is continuously measured on a measuring wheel positioned at an angle of 20 degrees in the direction of travel. The ratio of the measured sideway force and the known normal force results in the sideway force coefficient (µ). This is used to assess skid resistance of road surfaces.
MEFA (multi-functional detection system for road surface analysis)
Like the EFA measurement system, the MEFA measurement system is a combined evenness measurement vehicle that simultaneously measures the longitudinal and transverse evenness on roads. Furthermore, the vehicle has the capability to record road surface images to assess surface damage. The monitoring of longitudinal evenness is made by five laser probes which operate in accordance with the HRM principle with two different measurement base lengths. Transverse evenness is monitored by a laser scanner. In contrast to the MESOB measurement system, the recording of surface images is made by two line scan cameras installed at the rear of the vehicle.
MESOB (measurement system to assess surface damage)
The MESOB measurement system is a measuring vehicle whose purpose is to record road surface images to evaluate surface damage. The recording of surface images is performed by two surface cameras mounted at the rear of the vehicle.
T3D (stationary 3D texture fields)
The T3D enables the stationary, three-dimensional detection of the texture of road surfaces in the areas of microtexture and macrotexture. It operates on the principle of fringe projection. Both a small, high-resolution measurement field (vertical resolution of 0.004 millimetres) and a larger measurement field (vertical resolution of 0.04 millimetres) are available.
TL-5 (texture laser profilometer)
The TL-5 texture laser profilometer enables contactless monitoring of road surfaces in the macrotexture and megatexture area. The profilometer consists of a 5.5-metre-long bar with a displaceable laser measuring head and operates on the principle of triangulation. With this measurement method, the measurement interval is 0.132 millimetres at a vertical resolution of 0.0008 millimetres.
CPX (close proximity method measurement system)
The CPX is one of the currently available methods for measuring the acoustic properties of road surfaces. With this method, the acoustic properties of road surfaces, which depend, among others, depending on their texture, absorption capacity and homogeneity) can be monitored and correlated to the driven road section. These measurements of the tyre/road noise are carried out using microphones near the tyre-surface contact patch and special reference tyres possessing pre-defined characteristics.