What factor can affect the securing of metal coils during transport?

The shape and size of the coils are critical factors in how metal coils are secured during transport. Coils with different diameters, weights, and dimensions require different securing strategies to ensure they do not move during transit. For instance, larger coils may require heavier-duty straps or additional bracing compared to smaller coils. Properly securing the coils based on their dimensions helps prevent shifting or rolling, which can lead to damage or accidents during transport.

Considering other options, the temperature of the coils might influence their handling in terms of material properties but does not directly relate to securing methods. The color of the coils is irrelevant to their transport security, and while the time of day could affect visibility and safety during loading or unloading, it does not impact how the coils should be secured. Therefore, the shape and size of the coils stand out as the primary factors influencing their secure transport.