Have you ever driven by a truck weigh station on the interstate highway? Or perhaps you’ve driven by a feed processing plant and noticed a truck scale out front? The odds are that most of us have done one or the other of the scenarios above. So, how does a truck scale work?

A truck scale is a large set of scales, typically installed permanently on a concrete foundation, either above ground or in a pit that is used to weigh trucks and their cargo. By weighing the vehicle both empty and when loaded, the load carried by the vehicle can be calculated. Typically the truck scale will have several load cells underneath the platform.

Truck scales can be installed above ground with a ramp leading up a short distance and the weighing equipment underneath or they can be pit mounted with the weighing equipment and platform in a pit so that the weighing surface is level with the road. They are typically built from steel or concrete and by nature are extremely robust. In earlier versions the bridge is installed over a rectangular pit that contains levers that ultimately connect to a balance mechanism. The most complex portion of this type is the arrangement of levers underneath the weighbridge since the response of the scale must be independent of the distribution of the load. Modern devices use multiple load cells that connect to an electronic equipment to totalize the sensor inputs. In either type of semi-permanent scale the weight readings are typically recorded in a nearby scale house or office.

Truck scales are usually utilized to either sell or charge by weight (Trade Approved) or by check weighing both axle weights and gross vehicle weights. This helps to stop axle overloading and possible heavy fines. Truck Scales are used in industries that manufacture or move bulk items, such as in mines or quarries, garbage dumps / recycling centers, bulk liquid and powder movement, household goods, and electrical equipment. Since the weight of the vehicle carrying the goods is known (and can be ascertained quickly if it is not known by the simple expedient of weighing the empty vehicle) they are a quick and easy way to measure the flow of bulk goods in and out of different locations.

A single axle truck scale or axle weighing system can be used to check individual axle weights and gross vehicle weights to determine whether the vehicle is safe to travel on the public highway without being stopped and fined by the authorities for being overloaded. Similar to the full size truck scale these systems can be pit mounted with the weighing surface flush to the level of the roadway or surface mounted.