A weigh station is an area along the side of a highway or road at which larger vehicles such as tractor trailers are subject to weighing and inspection. These areas are equipped with extremely large scales upon which the tractor trailer or truck can be driven, and an attendant will take note of the truck's weight. Some of the scales at a weigh station require the driver to bring the truck to a complete stop, while others will allow the driver to continue driving over the scale without a stop. Sometimes a truck will be pulled over for a more thorough inspection.
The weight of the truck is measured at a weigh station to ensure the safety of both the truck driver and other motorists. Many regions of the world have placed limits on how heavy a truck can be to prevent the loss of control of the truck or damage to the roadways. If a truck goes to a weigh station and is found to be over the legal weight for that roadway, the driver will be pulled off the road until the situation can be resolved. There are two general ways to resolve an overweight load: a divisible load can be broken down into smaller loads and loaded onto another truck, and a non-divisible load will require the driver to obtain an overweight license, which is a temporary clearance to operate on the roadway. Such trucks will often need escort vehicles.
A weigh station attendant may also do other types of inspections of a truck aside from a weight inspection. Vehicle paperwork may be inspected, as may the freight paperwork that outlines what is being hauled, where it is being hauled, and so on. A visual inspection of the truck may also be done to ensure it is operating safely and within all applicable laws. The driver's fuel log may be inspected to ensure he or she is adhering to all acceptable practices, and all fuel taxes are being paid. A driver can sometimes pay such taxes at a weigh station.
While most stations are permanent fixtures along roadways, portable weigh station units do exist. These are useful for rural roads or temporary situations that call for additional inspection and support. The system can be transported to a certain location and set up reasonably quickly to accommodate truck traffic, and it can then be torn down relatively quickly when the station is no longer needed in that location.