LTL carriers have increasingly shifted toward density-based pricing emphasis, promising more consistent and fair freight rates. With the latest NMFC updates now in effect, this shift became even more evident. But while accurate dimensions should determine accurate class and cost, many shippers are finding that Density Exception Rules can still complicate things.
These rules, often buried in carrier tariffs, can override your calculated freight class—even when you’ve provided exact dimensions and weight. If not understood, they can lead to unexpected charges, reclasses, and billing disputes.
Traditional LTL Pricing: How LTL Freight Quotes Are Calculated
In LTL shipping, you’re essentially paying for the space your freight occupies on a shared trailer. The NMFTA’s NMFC codes guide this process by using four key factors:
- Density: The total space your shipment occupies, measured by weight per cubic foot.
- Handling: How easily carriers can move or manage your shipment during transit.
- Stowability: How simple it is to store and arrange your shipment safely within the trailer.
- Liability: The level of risk involved in transporting your shipment, including potential damage or theft.
The NMFTA assigns each product a class based on these factors to determine the appropriate rate. The goal: align cost with how easy or difficult the freight is to move.
To simplify this process, the NMFTA recently issued Docket 2025-1, consolidating, removing, or adjusting many NMFC codes. The change included moving certain items to a 13-subclass scale based strictly on density, focusing on items without liability, handling, or stowability concerns.
Where Density Exception Rules Come In
While this update makes classification more density-focused, carriers often apply their own rules that override standard classing—especially when it comes to how freight fits in a trailer.
Here’s where Density Exception Rules come into play.
Carriers may change a shipment’s dimensions due to Density Exception Rules. Factors like height, width, and stackability influence how other shipments load into the trailer. These rules help carriers accurately calculate how specific shipments affect trailer space.
Common Density Exception Rules by Carriers
Density Exception Rules very by carrier and here are a few real examples from LTL carriers:
- Freight over 70” high is rated as if it were 96” high
- Non-stackable freight that’s over 45” high is rated at 96” high
- Freight that overhangs standard pallet dimensions may be billed at 102” width
The reason? These shipments prevent carriers from fully loading the rest of the trailer, even when the freight meets standard density class levels. Carriers use these rules to better account for unusable space.
Why Density Exception Rules Matter
Many shippers go to great lengths to ship accurately—they provide exact dimensions and weight, use density calculators, and pack their freight efficiently. Despite their efforts, carriers often reclassify shipments based on height-based exception rules that only become apparent after delivery. These unexpected changes lead to surprise invoice adjustments, billing disputes, and a great deal of frustration, especially when they believe they followed every step correctly.
How to Stay Ahead of Density Exception Rules
- Know Your Carrier’s Tariff Rules
Each carrier applies density exception rules differently. One carrier uses the provided dimensions to rate the shipment, while another applies a density exception rule and reclassifies it. Always check your carrier’s height, width, and stackability rules. - Watch Height Thresholds
Exception rules often trigger at specific heights—typically 48”, 60”, or 72”. A carrier can change your freight’s rating based on just a few extra inches. - Use Rules-Based Rating Tools
Transportation systems like ViewPoint allow shippers to apply rules-based logic to pricing. These tools factor in carrier-specific exceptions, helping avoid surprise charges.
Stay One Step Ahead of Carrier Rules
LTL carriers introduced density-based pricing to simplify shipping, but Density Exception Rules add a layer of complexity that catches most shippers off guard. These rules can override your calculated class and lead to costly billing surprises.
At TLI, we work closely with our carrier network to help shippers navigate these exceptions in advance—not after the invoice hits. If you’re seeing reclass charges you didn’t expect, our team can help decode the rules and keep your costs under control.