Research Projects - Safety

Automated weight control of heavy goods vehicles based on dynamic axle load weighing

The impact of heavy goods traffic on the road infrastructure is constantly increasing, with serious consequences for overall traffic. For the design of the road superstructure according to RStO (2012), only the heavy traffic load is taken into account, since studies have shown that a 10 t axle transition damages the road in the same way as 10^4 axle transitions with an axle load of 1 t (4th power rule). Also in the field of bridge design, the number and distribution of trucks plays a decisive role in the assessment of load capacity and service life.
Since the recording of the total weight in traffic is currently carried out exclusively on static scales, the vehicles must be pre-selected and diverted for testing.

The aim of the present research project is therefore to develop a highly accurate measuring instrument for the dynamic recording of axle loads in flowing traffic, which can measure overloaded and thus particularly harmful trucks in flowing traffic and thus enable the more targeted implementation of passage bans and their control also according to the actual total weight.
The following advantages can be achieved with the newly developed system:

• Protection of the infrastructure by monitoring the actual total weight and automatic initiation of administrative offence procedures (enforcement), and thus also an extension of the service life of the structures and a reduction of the economic follow-up costs.
• Avoidance of detours for freight traffic through graded weight restrictions, thereby avoiding traffic jams and increasing traffic safety.
• Relief of the police, which is otherwise involved in enforcing driving bans.
• Individual approach of truck drivers in the area in front of bridge structures (e.g. via dialogue boards or interfaces to logistics apps) with exit or diversion instructions: This optimises route behaviour and minimises individual misconduct. Advantages for traffic flow and traffic safety can be expected.

To this end, evaluation algorithms are being developed which are based on wheel loads and other parameters dynamically recorded by means of so-called Weigh-in-Motion sensors and allow conversion to static axle loads. The technological challenge in the evaluation of Weigh-in-Motion sensors is to convert the measured dynamic wheel loads into static wheel loads. Dynamic influences on the wheel loads are caused, for example, by the unevenness of the road, which can lead to the truck's chassis swinging up at the moment of crossing (dynamic axle load) and thus to a deviation from the load that would be present in the resting state (static axle load).

The research project FE 88.0164/2017 is supported by the BASt (Federal Highway Research Institute) on behalf of the BMVI.