His professional experience has left him a little environmentally sensitive. Research engineer Thomas Lundberg does not just see the surface where he is running, cycling or driving. He constantly checks the condition of the road and almost unconsciously registers any damage. Soon, VTI's technically advanced new testing vehicle will be able to see every detail and defect on the road surface and the surrounding area.

“My main field is road surface condition with a focus on paved roads, with many projects commissioned by the Swedish Transport Administration. Measurement technology has undergone rapid development in recent years, with an avalanche-like increase in the amount of data collected,” says Thomas Lundberg.

The national road network is measured annually with equipment designed for this purpose. The Swedish Transport Administration uses the results for its maintenance planning. Although more and more variables are being collected, so far the main focus is on rut depth to detect wear and deformation and measurements to determine longitudinal smoothness using the International Roughness Index (IRI).

The data helps the Swedish Transport Administration to plan maintenance, make forecasts and conduct follow-up to ensure that the budget is correct. The actual road surface measurement is carried out by two contractors, with VTI acting as controller and quality assessor. Thomas Lundberg is the project manager, both for the major review before each new procurement every five years, and for annual testing on different sections of the road network, where VTI takes measurements using reference equipment.

The latest addition is information on cracks and the appearance of the road section, such as road markings, road barriers, signs, etc. The latter measurement technique is based on measurements with a kind of light radar called LiDAR, which stands for Light Detection and Ranging. Two rotating lasers scan the road surface and the road section. This data is combined with images from 360-degree cameras to create a digital twin, he explains.

“The main focus right now is on a special technique that is not yet widely used in Sweden – rolling deflection measurement, which measures the bearing capacity of the road under a rolling load. This requires special equipment. VTI tried to develop this quite some time ago, but the project was abandoned. Now it is being done in partnership with the company ARRB Systems AB.”

Thomas Lundberg leads the project, which analyses and combines the results with other data. VTI is trying to determine what is best to use in the Swedish Transport Administration's Pavement Management decision support system. The Finnish Transport Infrastructure Agency is a co-funder of the project. When it comes to roads, Finland and Sweden have fairly similar conditions, according to Thomas Lundberg, who hopes that this will enable the two transport authorities to reduce their life cycle costs and think more long-term.

“Personally, I think this technique and its technology are definitely useful. Tradition has it that what is visible on the road surface often reflects what is underneath. This is not always the case, as new paving on top is not enough and the underlying layers need to be reinforced.”

This instantly makes one think of the landslide in Stenungssund. It just so happens that VTI took measurements of the affected section of the E6 motorway. When the results are ready, it will be possible to see what the bearing capacity of the road has been over the past two years, with the first year being dry and the last year being very wet.

Thomas Lundberg's proudest achievement at VTI is standardisation.

“Several of the measures I have developed have been introduced into the Swedish Transport Administration's decision support system. In particular, the measure verge depth, which describes whether the outer edges of the road are deformed or have sufficient kerbing. The measure has also been submitted as a proposal to the European Committee for Standardization (CEN, Comité Européen de Normalisation).”

VTI has now invested in replacing the current research tool for road surface measurement. The procurement of a new testing vehicle has come a long way. A supplier has been selected and the new testing vehicle will be delivered in August 2024.

“The testing vehicle will be state-of-the-art, with several new possibilities for research and development that will put VTI at the forefront again. It will be a very flexible measurement system that enables increased collaboration with other parts of the Institute, such as with researchers in driving simulation and the environment.”

Thomas Lundberg started at VTI immediately after completing upper-secondary engineering school and military service. His time at VTI is a very long story that can be summarised here.

“I started working with road surface measurement over 35 years ago. The technology was still young at that time, and I saw the introduction of the first production-adapted testing vehicles. The work has been varied, a combination of my own field measurements and research and development with good and knowledgeable colleagues. No two assignments are the alike. There has always been an exciting development. That is the main reason why I have enjoyed it and stayed on.”

Text: Gunilla Rech

Translation: CBG