What is the most common safety hazard when uncoupling a trailer on a soft surface?

When uncoupling a trailer on soft surfaces — wet ground, asphalt softened by heat, gravel, or unpaved lots — the landing gear can sink into the surface under the trailer's weight, causing the trailer to drop after the tractor pulls out. This can damage the trailer, cargo, and surrounding property, and can injure people. Prevention: park trailers on hard, level surfaces whenever possible. On softer surfaces, place landing gear feet on wide boards or steel plates to spread the load. Avoid parking on grades; if you must, chock the wheels in both directions. After lowering landing gear, look to confirm it is firmly contacting the ground before disengaging the fifth wheel.