The Netherlands has a very dense traffic network with almost 140,000 kilometers of roads. In order to be able to maintain roads properly, they must be inspected by qualified road stewards. However, the Center for Regulations and Research in Ground, Water and Road Construction and Traffic Engineering (CROW), notices that the number of certified inspectors is lagging behind. In addition, a report by the European Court of Auditors shows that maintenance budgets for roads are declining sharply, while road use is actually increasing.
Visual inspections are often carried out by inspectors on foot or by a team of inspectors driving a vehicle at slow speed. Whilst driven inspections improve safety, it is still a time consuming process. It is therefore important that these traditional inspection methods are renewed and that administrators should look for solutions based on automation. This way, the shortage of qualified road stewards can be managed, a better inspection can take place and work can be done more efficiently at lower costs.
INSPECH can detect and assess defects on the road surface based on video images collected during driven inspections, using vehicles fitted with HD
cameras, recording equipment and GPS services.
Road surface quality can be recorded quickly at normal traffic speeds. Assessments can then be made later by inspectors from behind their computer. The domain knowledge of human road inspectors has effectively been transferred into INSPECH and the system has been trained to recognize defects recorded in the video footage, automatically. The system contains algorithms that automatically classify road sections in accordance with the guidelines of Rijkswaterstaat (Dutch Department of Waterways and Public Works) or CROW (local regulations). Detailed damage reports are automatically created and made available through the online INSPECH portal, enabling road authorities to easily monitor the inspected areas with details of all detected damage. As a result, road inspections are performed better, faster and safer at lower operational costs.
On this page we present three use cases that illustrate how INSPECH eliminated common challenges in road inspection.
Measuring the lifespan of taxiways and platforms at airports
A well-known Dutch airport wanted to know the Pavement Condition Index (PCI) and the residual constructional lifespan of a number of taxiways and platforms. The PCI is an example of a technical approach, which requires a manual examination of the pavement. The index was originally developed by the US Army Corps of Engineers, but was later standardized by the ASTM. The surveying processes and calculation methods are documented and standardized by ASTM for airport roads and sidewalks. Commissioned by NACO Airport Consultancy & Engineering, Unihorn has carried out investigations of the pavement and drafted recommendations. What was special about this project was the way in which the input for the PCI determination was collected. Normally this is done manually but thanks to INSPECH this aspect of the PCI process was automated.
The current state of the asphalt and concrete pavements were recorded with HD video cameras and defect locations determined by GPS using a specially equipped Unihorn vehicle driven along the taxiways. Subsequently, the observable defects from the video images were identified by INSPECH in accordance with the criteria of the ASTM D5340-20 standard.
To determine the PCI values, Unihorn then built a database in MicroPaver with a section and sample unit layout. After entering the defects, the PCI values were calculated with MicroPaver.
Thanks to INSPECH, the condition of the airport pavement infrastructure has been mapped out completely, quickly and in detail for both the client and the airport. In addition, INSPECH allows automatic comparisons between multiple inspections, enabling trend analysis and PCI forecasting per sample unit. By comparing the PCI inspection results of previous inspections with the most recent results, a prognosis for the development of the PCI value for the next 5 years has been established.
Improving the overall maintenance of A-lanes A15
A-Lanes A15, a partnership between Ballast-Nedam, John Laing and Strukton, has been commissioned by Rijkswaterstaat (Dutch Department of Waterways and Public Works) to widen the A15 between Maasvlakte and Vaanplein within a Design, Build, Finance & Maintain DBFM agreement. The area includes 37 km of highway, the Botlektunnel, the Thomassentunnel and the Botlekbrug.
Every year, A-lanes A15 must demonstrate the contract requirements are met and has to draft an asphalt repair plan annually. Visual inspection is therefore crucial and damages must be recorded according to the visual inspection system of Rijkswaterstaat (the DWW method).
For this project it was important to be able to inspect OPA8 asphalt concrete. This is a fine and open asphalt concrete with a high percentage of hollow space (25%). As a result, the mixture deviates considerably from the regular open top layers, which meant that INSPECH had to undergo additional training. This was achieved in just a few days which enabled INSPECH to very quickly inspect the A15 as required.
Thanks to INSPECH, A-Lanes now have a reliable way to assess the condition of the asphalt road surfaces. In previous inspections, carried out by human inspectors, too many inconsistencies in assessment had arisen between different inspectors. Also over the years, the variations in inspection results mean that creating and managing maintenance plans proved difficult.
INSPECH assesses road condition in a consistent and repeatable manner, making it easier to draft maintenance plans and predict rates of deterioration of the infrastructure assets.
In order to meet the contractual requirements, it was important for the client to carry out the inspection as late as possible in the year and for an asset manager to have access to the results at any time in order to plan maintenance. Thanks to INSPECH, better maintenance planning is possible, which benefits both parties. The combination of collecting HD video images and inspecting the road surface with INSPECH cut the project lead time by more than half. This complies with the desired ‘postponement’ of the inspection to later in the year.