Brace system and method for a vehicle at a loading dock

To help hold a (trailer) bed of a truck or trailer steady at a loading dock as the truck is being loaded or unloaded of its cargo, a yieldable vehicle brace exerts a substantial, but limited, reactive force upward against the trailer's rear impact guard to resist the trailer's downward movement. In some embodiments, the brace holds the trailer bed stationary up to a certain load limit and provides the trailer bed with a controlled or dampened descent when the load exceeds that limit. In some cases, the reactive upward force exerted by the brace increases with the downward velocity of the trailer bed. The reactive force can be created by one or more pressure relief valves, hydraulic fluid passing through a flow restriction, a brake, a spring, or various combination thereof. Some embodiments of the brace include provisions for accommodating horizontal movement of the rear impact guard.