Question 1: May a fuel fill pipe opening be placed above the passenger floor level if it is not physically within the passenger compartment?

Guidance: Yes. In addition, the fill pipe may intrude into the passenger compartment as long as the fill pipe opening complies with §393.65(b)(4), and the fill pipe is protected by a housing or covering to prevent leakage of fuel or fumes into the passenger compartment.

Question 2: Must a motor vehicle that meets the definition of a ‘‘commercial motor vehicle’’ in §390.5 because it transports hazardous materials in a quantity requiring placarding under the Hazardous Materials Regulations (49 CFR parts 171-180) comply with the fuel system requirements of Subpart E of Part 393, even though it has a gross vehicle weight rating (GVWR) of 10,000 pounds or less?

Guidance: No. FMVSS No.301 contains fuel system integrity requirements for passenger cars and multipurpose passenger vehicles, trucks, and buses that have a GVWR of 10,000 pounds or less and use fuel with a boiling point above 0 deg. Celsius (32 deg. Fahrenheit). Subpart E of part 393 was issued to provide fuel system requirements to cover motor vehicles with a GVWR of 10,001 or more pounds. The fuel systems of placarded motor vehicles with a GVWR of less than 10,001 pounds are adequately addressed by FMVSS No. 301 and compliance with subpart E of part 393 would be redundant. However, commercial motor vehicles that are not covered by FMVSS No. 301 must continue to comply with subpart E of part 393.