This section does not apply for vehicles certified to the Tier 3 standards in §86.1816-18, including those vehicles that certify to the Tier 3 standards before model year 2018.

(a) A manufacturer may optionally certify heavy-duty diesel vehicles 14,000 pounds GVWR or less to the standards specified in §86.1816. Such vehicles must meet all the requirements of this subpart S that are applicable to Otto-cycle vehicles, except for evaporative, refueling, and OBD requirements where the diesel-specific OBD requirements would apply.

(b) For OBD, diesel vehicles optionally certified under this section are subject to the OBD requirements of §86.1806.

(c) Diesel vehicles certified under this section may be tested using the test fuels, sampling systems, or analytical systems specified for diesel engines in subpart N of this part or in 40 CFR part 1065.

(d) Diesel vehicles optionally certified under this section to the standards of this subpart may not be included in any averaging, banking, or trading program for criteria emissions under this part.

(e) The provisions of §86.004-40 apply to the engines in vehicles certified under this section.

(f) Diesel vehicles may be certified under this section to the standards applicable to model year 2008 in earlier model years.

(g) Diesel vehicles optionally certified under this section in model years 2007, 2008, or 2009 shall be included in phase-in calculations specified in §86.007-11(g).

(h) [Reserved]

(i) Non-petroleum fueled complete vehicles subject to the standards and requirements of this part under §86.016-01(d)(5) are subject to the provisions of this section applicable to diesel-fueled heavy-duty vehicles.

[76 FR 57379, Sept. 15, 2011, as amended at 79 FR 23736, Apr. 28, 2014; 81 FR 73992, Oct. 25, 2016]