How Much Does a Semi Truck Weigh?

Exactly how much does a semi truck weigh? The answer to this question is complicated. 

Missouri has several ways to determine the maximum weight for a semi truck and trailer combination. These limits may vary depending on where the truck travels and the cargo it carries.

Missouri also varies the load limits based on the size of the truck and trailer. A truck with more axles and a longer distance between its axles can carry more than shorter trucks with fewer axles.

Here is some information about how much a semi truck can weigh in Missouri.

Missouri Semi Truck Size Limits

Missouri and the U.S. Department of Transportation (USDOT) share the authority to set weight limits for semi trucks and other commercial trucks. In 1975, the federal government set the maximum legal weight for a semi truck and trailer combination traveling on interstate highways at 80,000 pounds.

So, in most cases, the answer to the question “How much does a semi truck weigh?” is 80,000 pounds. Any semi truck and trailer combination that must travel at least part of its route on an interstate highway must weigh 80,000 pounds or less.

However, the law has several exceptions.

The government refers to the 80,000-pound gross vehicle weight (GVW) limit as the legal limit. But the government recognizes that some situations might require the transportation of something heavier than 40 tons. 

Some examples given by the USDOT include:

  • Electric generators
  • Wind turbine blades
  • Manufactured homes

When a trucking company needs to carry oversize loads, it can apply for an oversize load permit from the state where it plans to travel. 

In Missouri, a semi truck plus an oversize trailer can weigh up to 160,000 pounds. A semi truck plus a specialized equipment load — such as a crane, rock crusher, or drill — can weigh up to 152,000 pounds.

Longer Combination Vehicles

You might have seen FedEx trucks, UPS trucks, or other long-distance freight trucks with multiple trailers. The government refers to semi trucks with multiple trailers as longer combination vehicles or LCVs.

LCVs can weigh more than a single tractor-trailer combination. But Missouri has three different limits depending on the origin of the truck. 

An LCV entering Missouri from Kansas can weigh up to 120,000 pounds. LCVs from Nebraska can weigh up to 95,000 pounds. LCVs entering from Oklahoma can weigh up to 90,000 pounds.

Agricultural Products

Missouri has different load limits for grain, livestock, and milk. When traveling on state roads rather than interstate highways, trucks carrying agricultural products can weigh up to 85,500 pounds.

Commercial Zones

Commercial zones around Kansas City, St. Louis, and other cities larger than 50,000 have different weight limits. In these areas, a semi truck and trailer combination can carry up to 22,400 pounds per axle, excluding the steering axle. This means that a standard tractor-trailer combination in a commercial zone can weigh up to 89,600 pounds.

How Weight Affects the Outcome of a Truck Accident

A typical car weighs about 2,000 pounds, while an SUV usually weighs about 5,000 pounds. 

A vehicle’s energy and momentum vary proportionally with the mass of the vehicle. This means that a typical semi truck and trailer combination has about 40 times the energy of a car or 16 times the energy of an SUV traveling at the same speed.

This weight difference will destroy a passenger vehicle in a truck accident. The amount of energy transferred from the truck to the passenger vehicle can cause catastrophic injuries to the brain and spinal cord of the accident victims.

When a truck driver negligently operates a semi truck or the trucking company negligently loads or maintains it, you can seek compensation for the injuries you suffer. And in an accident with a fully-loaded semi truck, you may need substantial compensation to pay for your injuries.