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Chock and Block
Chock and Block
Objective: Secure a vehicle or piece of equipment using the chock and block method.
How to Use This Module
Serious injuries can happen when a vehicle or piece of equipment moves while it is being
worked on. Chocking and blocking prevent movement and prevent injuries. For this module:
Review the information below on the purpose and techniques of chocking and blocking.
Ask your supervisor to demonstrate chock and block on different types of vehicles or
equipment.
Practice chocking and blocking while your supervisor observes.
Review the important points.
Take the True/False quiz to check your learning.
Background

Sometimes it is critical to make sure that a vehicle or towed equipment cannot move:
When a trailer or other towed equipment is being unhooked.
When a vehicle or any equipment on wheels is in the shop for work.
When workers are working under a vehicle or equipment on wheels.
Chocking the vehicle or equipment keeps it from rolling forward or backward. Blocking the vehicle or
equipment keeps it from falling on workers under it. The reason behind chocking and blocking is the same: se-
cure the vehicle or equipment to prevent movement. Movement can cause injuries or even death so it should
always be prevented.
Chocking
Workers can be caught between a vehicle and the equipment or a piece of equipment and the shop wall
because the proper chocking procedures were not followed. It is a simple concept, but many workers forget to
use this procedure when working with or around equipment. In some cases, workers have been killed or injured
because they have failed to follow this procedure.

AEX 192.1.08
Agricultural Safety Program, 590 Woody Hayes Drive, Columbus, OH 43210 The purpose of the chock is to secure the wheels and hold them stationary. When unhooking towed equip-
ment from a tractor or truck, make sure the tires on the equipment have been chocked to prevent the operator or
bystanders from being injured if a roll back occurs. Do not rely on the equipments brakes. The rear-most axle
should be the one that is chocked. Tires may need to be chocked in both the front and the rear on some equip-
ment.
Blocking
When working on equipment, never rely only on jacks or hoists to support the equipment. The equipment
should be blocked to support it while you are working on it. Use jacks or hoists only to raise the equipment.
Then, build a platform of solid blocks to hold the equipment up in place. Be sure to keep your hands, fingers,
and feet away never put them between the equipment and the blocks.
Tips to Remember
Chock wheels at the rear axle.
Do not unhook equipment that has not been chocked.
Never put hands, fingers, or feet between equipment and blocks.
Double up and alternate the positioning of blocks while building the platform.
Use larger blocks on the bottom. Make the platform as wide as possible.
Review the Following Points
Rear axles need to be chocked.
Do not attempt to unhook equipment that has not been chocked.
Never put hands, fingers, or feet between equipment and blocks.
AEX 192.1.08 About These Modules
The author team for the training modules in the landscape and horticultural tailgate training series includes
Dee Jepsen, Program Director, Agricultural Safety and Health, Ohio State University Extension; Michael
Wonacott, Research Specialist, Vocational Education; Peter Ling, Greenhouse Specialist; and Thomas Bean,
Agricultural Safety Specialist. Modules were developed with funding from the Occupational Safety and Health
Administration, U.S. Department of Labor, Grant Number 46E3-HT09.
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the
author(s) and do not necessarily reflect the views of the U.S. Department of Agriculture or the U.S. Department
of Labor.
Answer Key: 1 = F, 2 = T, 3 = F, 4 = T, 5 = F.
OSU Extension embraces human diversity and is committed to ensuring that all educational programs conducted by Ohio State
University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, age, gender identity or
expression, disability, religion, sexual orientation, national origin, or veteran status.
Keith L. Smith, Associate Vice President for Agricultural Administration and Director, Ohio State University Extension
TDD No. 800-589-8292 (Ohio only) or 614-292-1868
Copyright © 2006, The Ohio State University
AEX 192.1.08 Chock and Block
Name____________________________________
True or False?
1. There is no need to chock equipment before it is unhooked from the vehicle.
T
F
2. The purpose of the chock is to pin the wheels and hold them stationary.
T
F
3. It is fine to support a vehicle with a jack while you are under the vehicle.
T
F
4. When chocking a loaded wagon, chock the rear axle.
T
F
5. Blocking a vehicle is only necessary when a trailer is attached.
T
F
Copyright © 2006, The Ohio State University

AEX 192.1.08
Agricultural Safety Program, 590 Woody Hayes Drive, Columbus, OH 43210