Blocking is used to: Before you start the test, please answer the question below regarding your insurance status. Without insurance you will not be able to drive in Ohio Do you currently have car insurance? Yes I have insurance. Great, you're all set! Click here if you still want to compare rates. No, I need insurance and I want to compare options. Question Blocking is used to: Answers Keep cargo in a large box. Prevent cargo from sliding in a trailer. Prevent cargo from falling out of a trailer. Explanation Blocking may be used on all sides of a piece of cargo to keep it from sliding while the vehicle is in motion. This questions appears in the following tests: Alaska Class A Knowledge Test Arizona Class B Knowledge Test Connecticut Class A Knowledge Test Idaho Class B Knowledge Test Iowa Class B Knowledge Test Kentucky Class A Knowledge Test Montana Class A Knowledge Test New Mexico Class B Knowledge Test Oklahoma Class B Knowledge Test Oklahoma Class B Knowledge Test Rhode Island Class A Knowledge Test South Carolina Class B Knowledge Test