This over the road container has pressure under 40 psi, and typically carries about 7,000 gallons. Which DOT specification does it represent?

• A. DOT 412
• B. DOT 407
• C. DOT 306
• D. DOT 105

Answer: (B)

The main idea here is recognizing how highway cargo tanks are classified by their design pressure. A container with pressure under 40 psi and a typical capacity around 7,000 gallons is designed as a non‑pressurized cargo tank. That matches the DOT specification for non‑pressurized tanks used to carry liquids with vapor pressures that don’t require higher pressure containment.

DOT 407 is the designation for these non‑pressurized cargo tanks, commonly seen hauling flammable liquids like gasoline and other fuels. The 7,000‑gallon size is a typical capacity for this spec, which is why this option is the best fit.

The other specifications involve different pressure ranges (low‑pressure or high‑pressure) or different uses, so they don’t align with a tank rated under 40 psi and around that gallon capacity.