WIM system output

Detailed individual data (per vehicle):

Besides measuring the gross vehicle weight, axle group loads, axle loads and often wheel loads of the passing vehicles, a WIM system will also determine other parameters related to the vehicle and its passage over the WIM system. This is combined in what is often referred to as the ‘Vehicle Record’, consisting of:

  • Unique identification (registration) number
  • Date and time stamp (yy-mm-dd + hh:mn:ss:cc)
  • Location: road number, direction, traffic lane
  • Number of axles and axle distances
  • Total vehicle length and/or wheel base
  • Vehicle classification
  • Vehicle speed

And in some cases

  • Single/double tyre detection
  • Lateral position of the vehicle
  • Tyre pressure distribution
  • Calibration coefficient (of the WIM sensors)
  • Error code (to validate or eliminate measurements)

Depending on the application, a WIM system may be combined with other sensors or devices. In such cases the vehicle record may be extended with:

  • Height and/or width of the vehicle
  • Identification number (tag) of the vehicle
  • Overview picture of the vehicle
  • Picture of the licence plate or registration number
  • Licence plate or registration number
  • Picture of dangerous goods identification shield
  • Code of dangerous goods shield
  • Vehicle signature
  • Temperature of the pavement or bridge, at one or several locations;
  • Deflection of the pavement
  • Bridge dynamic amplification factor.

Aggregated data (per time period):

These data consist of part or all of the individual measurements summed or averaged over a given period of time (e.g. 6 mn, 1 hr, 1 day, 1 week, 1 month, 1 yr).
Among others:

  • Traffic classification (% per types of vehicles over a given time period)
  • Classified flow: mean number of vehicles or axles of a given type per time unit
  • Histograms of any of the detailed data (type/class of vehicles, speed, vehicle length or axle spacing, GVW or axle load, etc.)
  • Means, standard deviations, fractiles of any of the detailed data

Some WIM systems provide only aggregated data, which limits the storage capacity. The aggregated data may be calculated afterwards.

Short time aggregated data (e.g. 6 mn, 1 hr) are used for real time traffic information and management. Long time aggregated data (1 week to 1 yr) are used for statistics, traffic monitoring and road operation or maintenance.