system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What actually happens at a truck weigh station

I’ve never understood what the point of a weigh station. Sometimes tucks don’t stop at them and I’m confused?
gpt
The weigh station is a place for the DMV and the police to perform routine control of vehicles. Their names comes from the big scales that are required to make sure big trucks are not carrying too much cargo and might be a hazard to drive. But there are usually many different types of vehicle inspections that could be done at the site. Before the weigh station there is usually a sign or a light instructing that might instruct the trucks to report for inspection. But if there are no inspections currently taking place then these signs will instruct them to just pass the weigh station. There are different laws regarding what trucks have to report for inspection and under what conditions in the different states. But a lot of times trucks that does not carry any cargo will be allowed to pass and if the weigh station is full they will also be allowed to pass. Sometimes there is someone controlling a light and will pick out only certain trucks for inspection and let the others pass. In addition to the lights and the signs the weigh station might also be in touch with the truckers using CB radio so the truckers might have been given other instructions then the sign say.