Monitoring the Static Vehicle Load on a Heavy Goods Vehicle

Static vehicle load can be calculated accurately from measurements of axle strain. This paper describes, in outline form, a series of laboratory and field tests on an instrumented heavy goods vehicle. The vehicle was instrumented in the laboratory and an extensive series of calibration tests performed to establish the relationship between measurements of axle strain and vehicle load; this testing regime was also used to validate the instrumentation. A field trial was then conducted with the vehicle being returned to service and axle strain measurements being recorded continuously. Estimates of the static load were then validated against daily weigh -bridge measurements. The system has been in continuous service for several years now and has proven to be a robust and accurate method of calculating static vehicle load which can be easily installed on a vehicle at relatively low cost. When combined with a vehicle tracking unit real time load data can be made available to a fleet operator and on the spot load data displayed to the driver. Inadvertent overloading, with all its implications for safely and road damage, can thus be avoided.