Flatbed truck tarps are harder to come by, although various dealers of tarps carry sizes large enough to cover a load for either a flatbed or dump truck. For tarping your own flatbed, here are some of the highlights in the video:

• Have a forklift driver bring the tarp up to the top of the load. Applying the tarp needs to start from the top of the load and go down.
• Once the tarp surrounds the load, bungee cords need to go through all D-rings. The bungee cords are either attached through two D-rings or attached from a D-ring to the side of the flatbed truck.
• Flatbed tarps designed to cover a load of lumber in the video have side flaps. Although the tarp around the load is secured under the flaps, the flaps themselves shouldn’t be blown about by the wind, as any wind getting under the tarp can cause wind whip and tearing. This portion of the tarp should be secured with bungee cords after the rest of the tarp has been.
• All hooks attached to D-rings should face outward. Otherwise, the metal might cut through the tarp.

(3) Any vehicle operating on a paved public highway with a load of dirt, sand, or gravel susceptible to being dropped, spilled, leaked, or otherwise escaping therefrom shall be covered so as to prevent spillage. Covering of such loads is not required if six inches of freeboard is maintained within the bed.

(7)(a)(i) A person is guilty of failure to secure a load in the first degree if he or she, with criminal negligence, fails to secure a load or part of a load to his or her vehicle in compliance with subsection (1), (2), or (3) of this section and causes substantial bodily harm to another.

The rest of the rules specific to Washington state can be read on the blog post here.

One key point in reading these regulations for covering a truck load is that how to or what to cover the load with isn’t specified. As with truck tarps, some materials need waterproof covering, while others just simply need a cover to not spill out of the truck. Two common types of truck tarps are mesh tarps and poly tarps, both of which can be applied manually or by a roll-on mechanism. While in the case of Washington state a load six inches below the edge of the truck doesn’t need to be covered, not covering materials still has a risk of having materials fly out. Using even a light or mesh tarp can be beneficial in keeping the materials inside the truck.