What type of lettering is required for markings on transport units?

Legible lettering is essential for markings on transport units because it ensures that the information is easily readable from a distance and under various conditions. Clear visibility of markings is crucial for safety and compliance, as it allows other drivers, emergency responders, and inspection personnel to quickly identify important details about the transport unit, such as hazardous materials being transported or necessary regulatory information. This is especially important in emergency situations where quick recognition can prevent accidents and ensure the safety of everyone involved.

Using lettering that is bold, italic, or colored may enhance visibility to some extent, but if the lettering is not legible, it defeats the purpose of the markings. Therefore, legibility takes precedence, making it the correct answer regarding regulatory requirements for markings on transport units.