The majority of InTek Logistics’ freight business is moving loads for shippers needing either 53’ domestic intermodal or truckload capacity. While both freight modes offer the same cube (ish), there are a few differences shippers should know, with weight being the heaviest (get it?) issue.
Loading a truck more than it is legally allowed to be carried on the interstate is … well illegal. Public safety is number one and the Department of Transportation (DOT) takes its responsibility to ensure roads are safe very seriously. So, if the load leaves a shipper facility illegal, there is the potential of financial costs being levied for DOT fines; rework charges to make the load legal; delays in shipping on-time; and the possibility for huge lawsuits if the shipment that was loaded heavy were to be involved in a fatal accident.
With all that in mind, let’s go through how much can be loaded on the various types of semi truck freight moving on the interstates today - including intermodal drayage as well.
The rule of thumb for each 53’ freight mode is what we have outlined below, but know there are exceptions to the rules which we will cover in more detail through this article.
Total legal cargo weight for truckers
Dry Van Trailer: 44,000 to 45,000 pounds- Intermodal: 42,500 pounds
- Refrigerated Reefer Trailer: 42,500 to 44,000 pounds
- Flatbed Trailer: 48,000 pounds of cargo
The reason the answer depends is the total legal amount a carrier can weigh in transit on the interstate is 80,000, inclusive of tractor, trailer and cargo weight and all but the cargo weight is variable.
Three variables that impact weight
The three variables that affect weight are the amount of fuel loaded, the type of tractor and type of equipment.
Fuel
The easiest of the three to cover is the amount of fuel loaded into the tractors diesel tanks.
Each gallon of diesel fuel weighs roughly 7 pounds, and with each big rig having between 120 and 150 gallon capacity, this means the weight of a tractor’s fuel is between 840 and 1,050 pounds.
While this doesn't sound like much by comparison, it can be the difference in operating legally on the road or not.
Semi Tractor
The next variable to discuss is the semi tractor itself. The two versions that we typically see on the road are day cabs and sleepers.
Day cabs run about the same weight, with the variable being single or double axle. Semi tractor sleepers are heavier and have a little more variability in their total weight, which is dependent on the size of the sleeper and how it is outfitted.
Freight equipment / mode
The last area to discuss on the topic of weight is associated with the type of equipment used for the various freight modes.
It's fairly easy to understand why flatbeds can be loaded much heavier than a dry van. They do not have walls or a ceiling, thus reducing two areas of weight the others have. On top of that, they are made of lightweight aluminum - further cutting heaviness.
Dry vans, temp controlled reefer equipment and container-on-flatcar (COFC ) intermodal are where trouble typically comes into play for the less experienced dock worker. The reason is they all look very similar from the outside, but the similarities end there.
A standard dry van typically can be loaded up to 44,000 to 45,000 pounds, where a temp controlled reefer can only be loaded between 42,500 and 44,000. The reasons for the lower cargo weight are the reefer's thicker walls lined with insulation along with its included refrigeration unit - both of which add more weight to the trailer.
The construction methodology of trailers can decrease the weight some between otherwise similar dry and refrigerated trailers and containers. Shippers can find a small contingent of lightweight trailer capacity in the market that can load roughly 48,000 pounds.
Motor carriers charge more for this capacity, but the overall cost per ton of freight moved will be lower because of the additional payload that can be put in transit. An example of an industry where lightweight trailers are often used is forest and paper products.
While there are a number of issues shippers need to be aware of when shipping intermodal versus truckload, the most common one for shippers transitioning their freight from truckload to intermodal is loading the container to be legally compliant with gross weight - and the distribution of that weight across the vehicle.
Both shippers and freight brokers find themselves in a world of hurt if they substitute intermodal capacity for what loaders expect to be a truckload request. The max payload for intermodal shipments is strictly 42,500 pounds, and there are additional steps a shipper must account for in loading an intermodal container to protect against load shifts that could put weight distribution into an illegal status.
The reason intermodal can only be loaded to a max weight of 42,500 pounds is the combination of a much more rigid container that must stand up to class 1 railroads double stacking on wellcars and a heavy duty chassis.
Our most read article for the past several years, Intermodal Weight: The Most Common Issue for Shippers is an article we suggest shippers read to ensure they understand what is required to protect against intermodal weight issues they may be unfamiliar with.
Weight distribution
The next challenge with weight is its distribution across the various points of a trailer and tractor, which are outlined below.
- Steer axle: 12,000 pounds or 6,000 pounds per tire
- Drive axle tandems: 34,000 pounds or 4,250 pounds per tire
- Trailer tandems: 34,000 pounds or 4,250 pounds per tire.
There are some exceptions to the distribution based on the distance between tandems. As an example, cases where the trailer axles are 10’ 2” apart each axle can weigh 20,000 pounds on the scales, allowing for the trailer axles to weigh a total of 40,000 pounds rather than 34,000 for closed tandem axles.
State exceptions to legal cargo weight
There are some state-by-state variations to the standards that allow shippers to load heavier based on the weight being distributed over additional axles.
Examples of variations to the DOT legal regulations include:
- Rocky Mountain Doubles – a tractor with two trailers: a long front trailer (usually 48 feet) followed by a shorter second trailer – maximum weight up to 129,000 pounds
- Turnpike Doubles – a tractor and two long (usually 48 feet) trailers – maximum weight up to 147,000 pounds
- Triples – a tractor and three short trailers (usually 28 feet) – maximum weight up to 110,000 pounds
- Michigan Octopodes – 8-axle double trailer combinations weighing up to 164,000 pounds.
Under this section we also want to share that California has bridge laws restricting the amount of weight allowed to cross, so we recommend getting familiar with these regulations also.
Navigating payload limits on highway freight
Again, the DOT takes the issue of legal weight of semi traffic seriously, as they and everyone should to ensure safe travel for commerce and citizens. So, if you should have further questions, please do not hesitate to reach out to us for more guidance.
Learn more about 53' domestic intermodal, truckload and managed transportation services.
