Chocking, also known as blocking, is done to prevent trucks and trailers from unintentionally moving, like rolling or overturning, while workers are loading, unloading, hitching, unhitching or servicing the vehicle. Unintentional movement is a scary and dangerous situation. It can cause injury and in some cases death.

CHOCKING BASICS 

Make sure you invest in chocks that are specifically designed for the type of vehicle you are driving, especially paying attention to size.

Never use a make-shift chock. That includes lumber, bricks, rocks or any other creative contraption you come up with on the fly. Use only proper wheel chocks that are manufactured and regulated to do the job right. 

THE IMPORTANCE OF UNDERSTANDING WHEEL CHOCK PROCEDURES

Wheel chocks are effective safety devices when used properly. However, wheel chocking procedures are not always as straightforward as they may seem. There are several key aspects to proper chocking that may not be obvious to every user. To ensure maximum safety for both workers and equipment, it is the responsibility of the end user to make the final determination about proper chocking of a vehicle under the circumstances presented. You cannot simply test a pair of wheel chocks with a specific vehicle on a specified grade and broadly assume that the wheel chocks will hold the same truck every time. 

Countless variables exist and must be considered when selecting the most appropriate wheel chock for each application. Thorough testing must be completed at each location to ensure that specific wheel chocks will meet their specific chocking requirements. In addition, wheel chocks require regular visual inspection for cracking, chipping or other deterioration signaling the need for replacement; however, they should require little or no maintenance.

VARIABLES TO CONSIDER BEFORE USING WHEEL CHOCKS – COMBINATIONS OF CONDITIONS 

• Wheel Size: Smaller tire diameters require smaller chocks, while larger ones require larger chocks.
• Gross Vehicle Operating Weight: Heavier vehicles require larger chocks than lighter vehicles.
• Level or Grade of the Ground Surface: Chocks need to be positioned in different ways depending on if the ground is level or not. Ensuring that the chocking configuration is correct based on surface grade is paramount for proper chocking.
• Radial Tires vs. Bias-Ply Tires: Radial tires deflect more than bias-ply tires. While this flexibility allows the vehicle to move more smoothly, it also allows the tire to wrap around the wheel chock, which reduces the chock’s effectiveness.
• Tire Pressure Variance due to Environment: It is important to monitor tire pressure, especially in harsh environments. Improperly inflated tires can lead to chocking failures.
• Condition of the Ground Surface: Whether the ground is firm, soft, wet, dry, icy, or frozen is a key determination in the type of chock to use. For frozen or icy terrains, choose a chock with a cleated bottom. For severely wet or muddy terrains, multiple chocks may be necessary to ensure safe chocking.

Choosing the Right Chocks: You’ll find wheel chocks in a wide range of sizes, which correspond to the sizes of various tires. Most manufacturers specify the tire height that their chocks are designed to accommodate, but there are other important considerations:

• Type of tire
• Chock material
  
• Road material
• Load weight
  

AN EMPLOYEE CHECKLIST FOR USING WHEEL CHOCKS

If you’re working in and around the loading dock, you should understand what wheel chocks are and why they’re used. You must also understand (and apply) the established communication procedures for confirming the status of the chocks. Failure to adhere to policies like this could result in the loading or unloading process beginning before the chocks are set and it’s safe to do so.

If you’re the one in charge of putting the wheel chocks into place, you have a great responsibility. Follow these steps to ensure you’re chocking the trailer properly:

1. Make sure the parking brake is set.
2. Use chocks in pairs.
3. Center the chocks against the wheel.
4. Always ensure the chock is centered and squared with the tire.
5. Position the chock snuggly against the tire tread.
6. Wheel chocks must be positioned downhill and below the vehicle’s center of gravity.
7. On a downhill grade, position the chocks in front of the front wheels.
8. On an uphill grade, position the chocks behind the rear wheels.
9. On a level grade, position the chocks on the front and back of a single wheel.

CHOCKING CAVEATS 

Other things to note:

• Chocks can easily slip on ice and snow, resulting in trailer creep
• They are often damaged, misplaced, and even stolen
• Employees responsible for setting them in place must take care to prevent back injuries

FINAL WORD

Chocking and blocking are good practices to prevent heavy loads and vehicles from unintentionally moving. 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.