Texas Compressed Natural Gas (CNG) Delivery Truck Driver Practice Exam

The correct height for horizontal guardrailing is 42 inches. This height is established as a standard in many safety regulations to effectively prevent falls and ensure that the guardrail provides adequate protection for individuals working or walking near elevated surfaces. The height of 42 inches is considered a sufficient barrier to be easily reachable while also high enough to prevent individuals from accidentally falling over the edge.

Other options present varying heights that do not meet these safety standards. For example, heights below 42 inches may not provide the necessary protection, while heights above have not been standardized in many safety guidelines and may not adhere to regulatory requirements. Thus, the selection of 42 inches aligns with recognized safety practices in construction and worksite environments.