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Cargo, hazmat, size & weight2 min read

Securing a flatbed load, paragraph by paragraph

Aggregate working load limit, tiedown count, and the commodity rules that override both — with the section printed beside each one.

Author
Relay Dispatch Desk
Published
17 Aug 2026
Verified
15 Aug 2026
Re-checked
annually

Key takeaways

  • The aggregate working load limit of your tiedowns must be at least half the weight of the article being secured.
  • Working load limit is a marked, rated figure — an unmarked chain contributes nothing you can defend.
  • Minimum tiedown counts are set by the length and weight of the article, before any commodity-specific rule applies.
  • Commodity-specific rules in §§ 393.116–393.136 override the general rules for the cargo they name.

Securement is one of the two things roadside inspectors are emphasising on the vehicle side this year, and it is almost entirely arithmetic. Get the arithmetic right and the judgement calls get much smaller.

The 50% rule

The combined working load limit of the tiedowns securing an article must be at least one half of the weight of that article. It is not a guideline and it is the first thing an inspector can compute at the roadside.

Article weight40,000 lb
Aggregate WLL needed20,000 lb
Four tiedowns at5,000 lb each
40,000 lb20 ft
Four tiedowns rated 5,000 lb each give an aggregate working load limit of 20,000 lb — one half of a 40,000 lb article, as § 393.106(d) requires. The tiedown count must also satisfy § 393.110.

Working load limit is a marked figure

Working load limit is the rated capacity of the tiedown, and § 393.108 sets out how it is determined. The practical consequence is blunt: a chain, strap or binder with no legible marking and no manufacturer's rating cannot be counted toward your aggregate. It may be holding the load; it is not holding up at an inspection.

Counting tiedowns

§ 393.110 sets the minimum number of tiedowns from the length and weight of the article, independently of the 50% calculation. Both tests have to pass — meeting the aggregate working load limit with too few tiedowns is still a violation.

When the commodity rules take over

Sections 393.116 through 393.136 give specific rules for named cargo, and where they apply they govern. If you are carrying any of these, read the specific rule before applying the general one:

Commodity-specific rules49 CFR Part 393 Subpart I
CargoWhere to look
Logs§ 393.116
Dressed lumber and similar building products§ 393.118
Metal coils§ 393.120
Paper rolls§ 393.122
Concrete pipe§ 393.124
Intermodal containers§ 393.126
Automobiles, light trucks and vans§ 393.128
Heavy vehicles, equipment and machinery§ 393.130
Flattened or crushed vehicles§ 393.132
Roll-on/roll-off and hook-lift containers§ 393.134
Large boulders§ 393.136

Sources

Re-verified annually. Educational summary — the regulation controls. Not legal advice.

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