Which feature is common to all tankers designed for hazardous material transport?

Tankers designed for hazardous material transport commonly include rollover protection and remote shut-off valves as essential safety features. Rollover protection is crucial because it helps prevent the cargo from spilling in the event of an accident or rollover, thereby minimizing environmental exposure and potential hazards to the surrounding area. Remote shut-off valves are vital for controlling the flow of the hazardous material during a leak or spill situation, allowing responders to manage the situation more effectively without putting themselves at risk.

The other options are not universally applicable. High internal pressure capabilities are specific to certain types of tankers, particularly those designed for liquids that require pressurization, but not all hazardous materials fall under this requirement. Aluminum construction is not standard among all tankers, as they can be made from various materials, including steel, depending on the type of hazardous material being transported. Lastly, while many tankers are designed with round shapes to distribute stress evenly, there are various tanker shapes used depending on cargo specifications, reinforcing that this is not a common characteristic across all designs.