Chocking is the act of using a wedge to immobilize the wheels of a vehicle or equipment to keep it from accidentally moving. Chocking the wheels of a vehicle, such as a truck or trailer, physically stops the movement of wheels to prevent runaways that can injure workers and destroy property.

Blocking is the act of using lumber to keep cargo in place. Blocking stabilizes cargo to prevent shifting and trailer overturns. Blocking also creates a physical barrier on equipment to prevent unintentional activation.

CHOCKING

• If you drive a truck, tractor, or other mobile equipment, use special caution when exiting the vehicle.

• Ensure the brakes are set, the vehicle is at a complete standstill, and that it will not roll forward or backward before you exit.

• To chock a freestanding vehicle place chocks on the left and right rear axle wheels.

• It is safest to chock both the front and back wheels on both sides of a vehicle.
• Some vehicle wheels may also need to be chocked at the front and back of each tire.

• To secure vehicles at loading dock, first make sure the trailer is backed up against the loading dock edges and place chocks on the left and right wheels that are closest to the loading dock.

• This placement allows a forklift to push down on the trailer wheels and seat them more firmly against the chock.
• When only the front axle is chocked, the forward motion of a forklift entering the trailer can loosen the chock, allowing the vehicle to creep forward or jump the chock.
• The safest bet is to chock both the front and back wheels on both sides of a vehicle.

• Only use chocks designed to be used with trucks, vehicles and equipment. Stay away from lumber, cement blocks, rocks, or other homemade items.

• Store chocks inside trailers so they are easy to find and readily available.
• Chain chocks to loading docks to keep them from being misplaced. 

HOW TO PROPERLY POSITION WHEEL CHOCKS

• Always ensure the chock is centered and squared with the tire.
• Position the chock snuggly against the tire tread.
• Always use wheel chocks in pairs.
• Wheel chocks must be positioned downhill and below the vehicle’s center of gravity.
• On a downhill grade, position the chocks in front of the front wheels.
• On an uphill grade, position the chocks behind the rear wheels.
• On a level grade, position the chocks on the front and back of a single wheel.

BLOCKING: Blocking is the act of using lumber to keep cargo in place. Blocking stabilizes cargo to prevent shifting and trailer overturns. 

• Block cargo to prevent loads from shifting during transport and unloading. If you don’t, a sudden shift in the center of gravity can overturn a trailer and unstable loads can strike, crush, or engulf workers when the materials are unloaded.
• Get in the practice of blocking all cargo – not just wheeled or round items.
• Items should be blocked separately and on all four sides with lumber and nails or spikes thick enough and long enough to keep the cargo in place.
• Drive nails or spikes into the lumber at opposing angles.
• Never use other cargo for blocking— it doesn’t prevent movement in the same way a block can and may cause your cargo to overturn.
• Keep your hands, fingers, and the rest of your body out of dangerous pinch points.

MORE SAFETY AND BLOCKING PROCEDURES – DO’S

1. Review the complete Standard Operating Practices for every year or at the start of the season when you will be using this type of equipment.
2. Machines and equipment should be supported with the manufacturer’s safety bracing system. 
3. Block both sides of wheels on partially raised farm equipment with trailing wheels.
4. Turn off tractor engine and set brakes during maintenance work, unless otherwise indicated by manufacturer.
5. Freight should be blocked when loading or unloading a trailer. Do not use other freight as a block. Use proper materials for blocking.
6. Use larger blocks on the bottom. Make the platform as wide as possible.
7. Double-up and alternate the positioning of blocks while building a platform.

One Important Don’t: Don’t rely on jacks, hoists or hydraulic systems to support raised equipment. 

BLOCKING PROTOCOL WITH EQUIPMENT/MACHINERY: It is critical to block all forms of hazardous energy including: potential energy due to gravity, hydraulic pressure, or any stored energy that may cause equipment to move or drift, such as electrical or mechanical energy. The lack of blocking allows equipment to move or drop, striking workers, which could lead to fatal and critical injuries. These events involve:

• raised blades of bulldozers;
• raised buckets of backhoes;
  
• raised boxes of dump trucks;
• raised forks of forklifts;
• punch presses;
• hoisting equipment.
  

FINAL WORD

If you are loading or unloading, hitching or unhitching, or performing maintenance on a vehicle, you must take time to chock and block the equipment to protect you and others from unintended movement of the equipment and/or cargo.