Source: https://cms.fmcsa.dot.gov/print/regulations/title49/section/393.100
Timestamp: 2019-04-25 22:32:24+00:00

Document:
Section § 393.100: Which types of commercial motor vehicles are subject to the cargo securement standards of this subpart, and what general requirements apply?
Question 1: When securing cargo, is the use of a tiedown every 10 linear feet, or fraction thereof, adequate?
Guidance: Yes, as long as the aggregate strength of the tie-downs is equal to the requirements of §393.102 , and each article is secured.
Question 3: Are the requirements of §393.100  the only cargo securement requirements motor carriers must comply with?
Guidance: No. A motor carrier, when transporting cargo, must comply with all the applicable cargo securement requirements of subpart I and §392.9 .
Question 4: Do the rules for protection against shifting or falling cargo apply to Commercial Motor Vehicle (CMV)s with enclosed cargo areas?
Yes. All Commercial Motor Vehicle (CMV)s transporting cargo must comply with the applicable provisions of §393.100 -393.106 (subpart I) to prevent the shifting or falling of cargo aboard the vehicle.
Sec. 393.100(b)(2), Option B, requires one tiedown assembly for each 10 linear feet of lading or fraction thereof. However, "a poletrailer* * * is required only to have two * * * of those tie down assemblies at each end of the trailer," i.e., at the stanchions, because the cargo cannot effectively be secured at mid-trailer where its structure is limited to the pole or boom.
Sec. 393.100(b)(4), Option D, allows the motor carrier to use a securement system that is similar to, and at least as effective as Option B.
Sec. 393.100(d) states that the rules in §393.100  do not apply to the transportation of "one or more articles which, because of their size, shape, or weight, must be carried on special purpose vehicles or must be fastened by special methods." However, since pole trailers are explicitly included in §393.100(b)(2), they are not special purpose vehicles and logs must be secured in accordance with §393.100(b).

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