SPDE (System for Pavement Distress Evaluation), Figure 1, is a device that incorporates several measurement subsystems and is programmed with common software. The integration of various devices within a single measurement system and the ability to conduct real-time measurements under normal traffic conditions makes it possible to obtain full compatibility of pavement parameter data and significantly increases the efficiency of the conducted evaluation of pavement surface features.

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Fig. 1 SPDE system

The measurement system can be used to study such pavement characteristics as longitudinal and transverse profile, theoretical rut water film depth, longitudinal and transverse gradients of the road, radii of horizontal curves of the road, and pavement texture. For this purpose, there is a beam mounted on the front of the vehicle with laser sensors of different characteristics installed. The sensors are spaced every 12.5 cm, and with special angle sensors, the effective measurement width has been increased to 3.5 m. The whole thing is instrumented with additional elements such as a gyroscope, accelerometer, 4 sensors for measuring longitudinal profile (fixed in the axis of the right wheels, under the car) and an additional laser sensor with slightly different characteristics, designed to measure texture.

The SPDE also allows recording a digital image of the pavement surface and the damage present in it over a width of up to 4 m with a resolution of 1 mm x 1 mm. By using LED lighting technology, it also remains insensitive to changing lighting conditions (Figure 2). The flashes of LED light have a high intensity in the recorded light spectrum, which exceeds the intensity of daylight several times. The image of the pavement surface is captured by two cameras at the rear of the car. In addition, a camera is placed on the front of the vehicle to record the image of the Right-of-Way, so that it is possible to measure and identify RoW elements.

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Fig. 2 Recording images of the carriageway surface with the SPDE system

Thanks to the use of advanced measurement technologies, the data obtained during the measurements are very detailed and allow the precise location of identified sections with inferior surface parameters. The large data resource provides an opportunity to implement new, more precise methods of interpreting and assessing the condition of road pavements.

Profile testing with the SPDE Profilograph is covered by the scope of accreditation of the Testing Laboratory No. AB 426, issued by the Polish Centre for Accreditation.