What must be ensured for letters used in markings on transport units?

Ensuring that markings on transport units are legible is essential for safe and effective communication. Legibility allows other drivers, emergency responders, and inspectors to quickly and accurately identify the contents and any relevant safety information related to the transport unit. This clarity is crucial for maintaining safety protocols and compliance with regulations.

While uppercase letters can enhance visibility and readability, the primary focus is on ensuring that all markings are clear and easily understood. Similarly, colorful or reflective elements might contribute to visibility, but without legibility, the purpose of the markings is compromised. Thus, the emphasis on legibility directly aligns with safety practices in the transportation of materials, especially hazardous substances, ensuring that information is communicated effectively under various conditions.