Safeguarding municipal infrastructure with short-term WIM measurement

The Slovenian municipality of Žalec recently made several investments in infrastructure, which is why the local authorities decided for a one-week bridge weigh-in-motion (WIM) measurement on one of their more problematic road sections. The aim of the measurement was to gather data on traffic loads; specifically, they were interested in the local sources of heavy traffic—these are heavy vehicles from local quarries, construction sites, lumber mills, etc. Such traffic can be problematic for two reasons: first, there is almost no monitoring of heavy vehicles on local roads. And second, local roads are not designed for high traffic loads.

We used our SiWIM MkIV bridge WIM system to perform the measurement. Since all of the equipment is installed under the bridge, the HGV drivers do not know a WIM measurement is taking place, which assures the accuracy of the data.

Although a week-long measurement may seem short, our experience shows the incredible value of short-term WIM measurement, which was again proven in our project in Žalec. We identified groups of lorries that were driving overloaded every day at the same hour from a local wasteyard, returning empty in the afternoon. This information is useful for local authorities, which have a very limited budget when it comes to the supervision of overloaded HGVs.

We also calculated the estimated reduction in the service life of the road section due to overloading. Such a calculation is critical for planning a long-term budget for infrastructure maintenance, while it also shows decision-makers in an unambiguous way the effect of overloaded vehicles on the lives of ordinary people, as money spent repairing the road damage could be used in other areas.