Cargo Securement: Working Load Limit and Tiedowns
Maryland's Cargo Securement domain tests whether a load stays on the vehicle in normal driving and emergency maneuvers. The exam focuses on working load limit, number of tiedowns, and protection of vehicle lights and occupants.
The securement standard
The aggregate working load limit (WLL) of all tiedowns must be at least half the cargo weight. WLL is the manufacturer's rating, not the breaking strength. Use at least the minimum number of tiedowns: one for an article up to 5 feet long and 1,100 pounds; two for longer or heavier articles; and additional tiedowns as weight and length increase. Use direct tiedowns for logs, pipes, and other round articles. A headboard, front-end structure, or side kit helps contain the load. Cargo must not obscure lights, reflectors, or plates, and nothing may leak or blow off.
Inspection and adjustment
Check tiedowns at the start, after the first 50 miles, and every 150 miles or 3 hours thereafter. Recheck after hard braking or a load shift. Use edge protection to prevent straps from being cut. Do not attach a chain to a fuel tank, brake line, or other unsafe point.
Worked example
An 8,000-pound load needs aggregate WLL of at least 4,000 pounds. If each strap has a WLL of 1,000 pounds, use at least four straps, and still satisfy the minimum tiedown count for the article's length. Four straps meet the WLL calculation only if they are rated and attached correctly.
Traps
Confusing breaking strength with WLL; counting tiedowns without adding their WLL; skipping the 50-mile recheck; using damaged straps; failing to protect sharp edges; and leaving the load higher than the headboard.