VTI leads trials in Germany: “Significant differences"
Thomas Lundberg checks the equipment during the trials in Germany.
The Swedish National Road and Transport Research Institute (VTI) was in charge of research when road surface monitoring systems from 13 countries were tested and compared. The results demonstrated important differences, as well as providing welcome confirmation of the quality of VTI’s new road surface measurement vehicle, which was assessed as “very capable”.
In October 2024, the DuraBASt facility in western Germany welcomed 23 road surface monitoring vehicles from countries ranging from Finland in the north to Italy in the south. The journey there was a long one, taking up to three days by road for the vehicles form the farthest flung participants.
The facility outside Cologne, which is operated by the Federal Highway and Transport Research Institute (BASt), consists of various sections of road with differing structures and levels. During the trial week in October, 23 European road monitoring systems were tested on their ability to measure parameters such as unevenness, position, cracks, and width under VTI’s leadership.
Each vehicle completed eight to ten circuits at two speeds: 30 and 40 kilometres per hour. The data collected was then compared with values obtained by VTI’s specialised reference equipment. VTI’s own road surface monitoring vehicle, the Mobile Research Platform (MRP), which has been operational since September 2024, was also evaluated.
“Our vehicle was assessed to be very capable, finishing in the upper half in all tests. It was also able to supply data on all investigated variables, which was not the case with all systems. This was a welcome check on whether the system really does deliver as intended,” says VTI research engineer Thomas Lundberg, who was in charge of the trials.
The tested systems can be divided into three categories: profilometers, which use laser-based measuring techniques such as point lasers or line lasers; mobile mapping systems, which use LiDAR scanners; and connected vehicle and smartphone solutions, which use the vehicle’s own sensor or extra accelerometers. VTI’s vehicle is a profilometer equipped with LiDAR, so it falls into both the profilometer and mobile mapping categories.
The tests show significant differences between the three categories, but also between different systems and operators (see fact box).
“While all of the technologies fulfil their function, mobile mapping generally generates the most robust results. This technology has mainly been used to create digital twins, but is now so accurate that it can also examine road surfaces. It was something of a breakthrough,” notes Lundberg. “The differences between operators were significant, and a couple produced fairly poor results. I think this might give some transport authorities pause for thought.”
Lundberg hopes that the trials will make it easier for transport authorities to order different road monitoring services in the future. Previous procurement processes have excluded certain systems, but it is now clear that, for example, mobile mapping systems could be a perfectly good option. The trials also used several new variables that have not been used previously by authorities in all countries.
“This will be an important benchmark for various systems and technologies that benefit the entire industry,” says Lundberg.
Read the report: Road surface monitoring equipment evaluation 2024 in Cologne: The duraBASt test
Read more: DuraBASt homepage
Håkan Wilhelmsson was one of the VTI employees who was on site in Germany.
Facts: Some significant results
- Mobile mapping systems demonstrated the highest validity and repeatability across most parameters, although certain profilometers achieved similar results.
- Connected vehicle solutions generally had the poorest agreement with reference and poorer repeatability.
- Mobile mapping systems achieved 81 per cent validity and 0.13 mm/m repeatability on the International Roughness Index (IRI), a generally better result than the other categories.
- With regard to longitudinal profile, all systems demonstrated good agreement with reference data for wavelengths between 4 and 10 metres. Performance deteriorated outside this interval.
- Most systems met the repeatability requirements set by Swedish standards for longitudinal profile measurement.
- Most systems were capable of accurate positioning (latitude, longitude, height), with deviations of only a few centimetres.
- Lane width measurements were highly precise, with most systems accurate to within one centimetre of the reference measurement.
VTI's new road surface measurement vehicle and rolling research platform performed well in the test.
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