Semi trucks are the backbone of the U.S. transportation industry, moving essential goods to and from all parts of the country. The weight of these vehicles, though, is extremely important to consider when working to ensure road safety, maintain infrastructure, and comply with legal requirements.
Understanding how semi-truck weights are classified, the weight limits and restrictions imposed on them, and the importance of weigh stations helps keep the road a safer place for everyone.
Understanding Semi Truck Weights
Semi-trucks are classified based on their gross vehicle weight rating (GVWR), which includes the combined weight of the truck, the trailer, the cargo it’s carrying, and any passengers inside.
Unladen vs. Laden Weight
A semi truck’s weight will vary based on whether the vehicle is empty or fully loaded:
- Unladen Weight: The weight of the truck without cargo (the cab of the truck alone can weigh from 10,000 to 25,000 pounds)
- Laden Weight: The total weight when fully loaded (the cab and cargo combined can weigh up to the federal limit of 80,000 pounds)
These measurements help determine where a truck can travel and what roads or bridges it can pass over safely.
Semi Truck Weight Classifications
The Federal Highway Administration (FHWA) assigns one of eight weight classes to trucks. These can be split up into the following groups:
- Classes 1-3: Light-duty vehicles weighing up to 14,000 lbs
- Classes 4-6: Medium-duty trucks weighing between 14,001 and 26,000 lbs
- Class 7: Heavy-duty trucks, as well as city buses, that weigh between 26,001 and 33,000 lbs
- Class 8: Semi-trucks and 18-wheelers that weigh 33,001 lbs or more
Most semi trucks will fall into Class 8, making them the heaviest vehicles on the road and, therefore, the most dangerous.
Why Is Semi Truck Weight Important?
The weight of a truck impacts nearly every aspect of transportation safety. The heavier a truck is, the more distance it requires to break and the more difficult it is to maneuver. Overweight vehicles increase the likelihood of dangerous and often preventable accidents.
Additionally, the heavier a vehicle is, the more wear and tear it will cause to roads, bridges, and other infrastructure, leading to costly repairs. The 80,000-pound limit enforced on semi trucks is meant to minimize these risks; ignoring the restriction could cause drivers and the companies they work for to face legal repercussions.
How Are Semi Trucks Weighed?
If a truck exceeds 10,000 pounds, it will typically be required to stop at a weigh station to ensure its compliance with weight restrictions. There are three ways in which semi trucks are weighed:
- One-Axle Weighing: The truck will stop at a scale, and each axle will be weighed separately
- One-Stop Weighing: The entire truck is weighed at once using multiple scales
- Weigh-in-Motion (WIM) Systems: Sensors embedded in the road weigh trucks without requiring them to stop at a station
There are a few exceptions wherein trucks can bypass a weigh station. If the vehicle is enrolled in an electronic bypass program, is an emergency vehicle, or is locally delivering cargo, it may be exempt, depending on state regulations.
What Happens if a Truck Is Overweight?
If a semi-truck exceeds legal weight limits, both the driver and the company they work for (if any) can face serious consequences, including the following:
- State and federal fines and penalties
- Offloading excess weight in the vehicle before resuming travel
- Legal liability and the risk of higher insurance costs
- Commercial driver’s license (CDL) violations
Truck drivers and their associated companies must always verify their vehicle’s weight to avoid these consequences.
Better Information Leads to Better Safety on the Roads
As some of the heaviest vehicles on the road, the weight of semi trucks plays a vital role in driver safety, maintaining infrastructure, and complying with state and federal legalities. By understanding how much semi-trucks weigh and why that knowledge matters, all drivers can ensure safer conditions on roadways.
