Measurement of Road Surface Condition

In this series of blog posts, we will explore various use cases for our products. Today, we delve into the technical aspect of measuring the depth of asphalt holes. Stay tuned for more informative content on how our products can assist in this specific application.

In the maintenance of roads, it is important to have an objective measure for the state of the road surface. Thus, the work can be concentrated on the most worn roads. An objective measure for the state of a road can be achieved by measuring longitudinal and transverse surface profiles from which roughness and rutting parameters can be derived.

In this use case up to 9 ODS sensors are placed on a rail mounted on the front of a car. An accelerometer is used to record vertical vehicle body accelerations, and one of the ODS sensors is used for measuring the displacement between sensor rail and the pavement. Longitudinal profile measurements are obtained by summing the twice integrated acceleration measurements with the appropriate rail-to-road displacement. Transverse profile and/or rut is obtained directly from all 9 sensor readings, referenced to the straight rail.This method allows for a detailed analysis of the road surface, enabling maintenance teams to identify specific areas that require repair. By combining data from the ODS sensors and the accelerometer, a comprehensive profile of the road can be created, highlighting both shallow and deep depressions. This information is crucial for prioritizing repairs and ensuring safer driving conditions. Additionally, regular monitoring using this system can help track changes in road conditions over time, allowing for proactive maintenance efforts before significant damage occurs.

9 ODS sensors will give a total of 9000 measurements (18000 bytes information per second), if the RS232 output is used. This would be a lot of data even for a powerful computer system. Therefore, the voltage output is used, which makes it is possible with an A/D converter system to perform a measurement precisely when desired and without having to consider interrupts and bit stream.

Because of the high measuring frequency of 1000 HZ it is possible to drive the car at a speed adapted to the traffic – i.e. 80 – 100 km/hour – and still get a good measurement of the road surface. The data are stored on a harddisk and can later be printed out as graphs. Because of noise in the measurements, originating from slippery and reflecting stones and from holes, where the sensor’s measuring range is exceeded, the results are averaged over at least 5 measureme