What is a defining characteristic of the DOT 406/MC 306 gasoline tanker?

A defining characteristic of the DOT 406/MC 306 gasoline tanker is that it is specifically designed for transporting non-pressure liquids. These tankers are constructed to carry hazardous materials, such as gasoline, that do not require pressurization for transport. The design features include rounded tops and a structure that can accommodate the expansion and contraction of the liquid inside while preventing leaks.

In contrast to pressurized tankers which need to withstand high pressure, the DOT 406/MC 306 operates under a different set of safety standards and does not carry liquids that require pressure containment. The design also accounts for the stability and safety needed while transporting flammable liquids but does so without the complexities found in pressurized systems.

While the tanker having a cylindrical cross-section is a feature of many tankers, it isn't exclusive to the DOT 406/MC 306 and does not particularly define its function. Similarly, while the tanker can carry up to 15,000 gallons, this capacity can vary and is not the primary defining characteristic. Thus, the emphasis on its suitability for non-pressure liquids is what truly sets it apart.