An essential part of a safe working environment when loading or unloading trucks and trailers is the proper use of equipment, which includes chocks and blocks. Every year, many workers are severely or killed because the wheels of a truck or trailer were not chocked. Vehicle drivers are also injured when trailers overturn because unblocked freight shifted during travel.
Accidents are caused each year when a truck or trailer rolls away from the dock because no one took time to chock the wheels. In some cases, drivers who got out of the cab were crushed by their own rig. In other cases, lift truck drivers were injured when the forklift fell between the dock edge and a trailer that moved away. To prevent this from happening, the wheels of trucks or trailers at a dock should always be chocked prior to the start of any operation. Lift truck drivers should never enter a trailer without first verifying that the wheels have been chocked, and that the floor of the trailer is in good condition and capable of supporting the weight of the forklift and the load. In most states, OSHA requires that vehicle wheels be chocked prior to permitting forklifts to enter trailers.
Positioning of chocks is important. The purpose of the chock is to pin the wheels and hold them stationary so that the tractor or trailer can't move. However, if they aren't placed in the right location, they will not prevent movement of the wheels. The safest procedure is to always chock the wheels closest to the dock, especially on a tandem-axle trailer. The reason is, the lift truck entering the trailer can exert a downward force which helps pin the wheels more effectively against the chock. When the front axle is chocked, the forward motion of a forklift entering the trailer may loosen the chock, allowing the trailer to move forward, or even jump the chock.
Shifting loads are hazardous. Freight inside the trailer must also be blocked or secured to keep the load from shifting, which can damage other cargo or cause a trailer to overturn in transit. Cargo does not have to be round, such as reels or machinery on wheels, to shift position. Blocking of heavier freight is used to prevent movement during transit. To accomplish this, it may be necessary to block each item separately, on all four sides. The type of blocking material used is also important. Make certain that nails are long enough to hold the block and that lumber is thick enough to prevent the cargo from shifting without breaking. Never use other freight as blocking. If it looks like the cargo can move around, it probably will. Take time to secure it.
Be sure the correct equipment is always available. Every loading dock should be equipped with chocks, which if properly used, will keep vehicles from moving while being loaded or unloaded, especially when forklift trucks are used. Chocks will more likely be available at all times if they are fastened to the dock with a chain or rope to prevent their "disappearance," and stored out of the traffic areas when not in use.
Chocks and blocks help avoid accidents. Use them, and require others to use them!
Wheel Chocks Guidelines: Application & Proper Use. Wheel Chocks Guidelines: Application & Proper Use, ESCO, 2018.