Weigh-in-Motion (WIM)
Dynamic axle load monitoring system TDS 821R/WIM
The monitoring of overloaded vehicles in flowing traffic is more necessary than ever before, as this causes considerable road damage. The cost of this damage is no longer to be borne by the general public but laid at the door of the instigator. As well as damaging the road, overloading also reduces traffic safety. The following effects also occur:
- Vehicles are unstable
- Vehicles are difficult to steer
- Braking distances are significantly increased
- Fuel consumption is increased
- Unfair competition in the transport industry
- Driver exhibits reduced concentration and tiredness (increased risk of accident)
Dynamic axle-load scales are used for the automatic detection of overloaded vehicles in flowing traffic (Weigh-In-Motion).
A powerful WIM system is produced when the TDS 821R/VDK 900 is expanded by the addition of function group FG 2. LINEAS quartz sensors from Kistler Instrumente AG are used for measuring the weight.
These provide data relating to the wheel, axle, axle group and gross weights of the vehicle, from which maximum loads are determined. Ultimately, these data are used to provide road operators with information relating to the loading of different network sections. These systems fall into the category 
WIM-S (Statistics).
Systems, which enable monitoring to be carried out by the authorities, have safety in mind. The measures undertaken by the police traffic monitoring unit or the Federal Office for Goods Traffic (BAG) include the specific checking of axle loads and vehicle gross weights of commercial goods traffic. Such systems fall into the category WIM-P (Preselection).
Consequently, the logical step was to develop the two systems described above to form an automatic WIM Enforcement System (WIM-E) which enables the wheel and axle loads as well as the gross weight of vehicles to be continuously monitored by dynamic weighing backed up by photographic evidence. If the loads are exceeded, the data are documented in a form that may be used as evidence in court and automatic fines are imposed.
The determination of the wheel, axle and axle group loadings (double and triple axles), as well as the gross weights of vehicles and classification according to axle silhouette and gross weight, is carried out in accordance with TLS 2002, FG2 or European Directives (European WIM Specification produced by the COST 323 Management Committee). The TDS 821/WIM system data can be accessed from a central point by various communications methods.
