One major factor is transportation. Land, air and sea vehicles enable us to deliver goods from one corner of the country to the other, on a scale unrivaled in human history. Without this ability, American life would be much, much different. Let’s examine how scales and balances factor into the trucking industry in America.

America is crisscrossed by a series of superhighways that enable anyone to get from Seattle to Key West, if they so choose, with relative ease. The blessing of these roads is that trucks can get from one place to another reliably, allowing food and durable goods to flow to consumers. The trucking industry is closely monitored in terms of the weights of the trucks carrying goods.

When traveling on superhighways, truckers are routinely required to use weigh stations ( also known as “chicken coops” ) and have the axle weight and gross weight of their trucks checked. There are a number of reasons for this. A primary reason is to limit the amount of weight that America’s bridges have to bear, preventing eventual bridge fatigue and collapse. The federally mandated weight limit is 80,000 pounds. If a truck goes over that limit, an overweight pass can be issued in certain circumstances. Another reason is to make sure that the truck complies with tax laws and equipment safety standards.

A variety of scales are available for this purpose. In previous decades, a truck was required to pull off the road into a weigh station. A large balance was used to weigh the truck while an officer checked the trucker’s paperwork. However, a more recent development in balance technology allows trucks to remain in motion while being weighed.

Now, trucks on American highways can use what is known as a pre-pass system. A transponder similar to the one used for automobile toll collection is mounted on the truck. This transponder contains all the necessary data authorities need to know, including a compliance and safety record. When a truck is one mile away from a weigh station, a reader mounted on a pole scans the transponder. Then the truck goes over a series of scales mounted into the road itself. The two sets of data are compared, and if the truck is in compliance, another reader pings the transponder and lets the driver know if a stop at the weigh station is warranted. Some of the time, a truck in compliance is given a “red light” anyway for a random check. The better a freight carrier company’s record is with regards to compliance, the fewer random checks are applied to its trucks.