(a) General provisions. The useful life values specified in this section apply for all exhaust, evaporative, refueling, and OBD emission requirements described in this subpart, except for standards that are specified to apply only at certification. These useful life requirements also apply to all air conditioning leakage credits, air conditioning efficiency credits, and other credit programs used by the manufacturer to comply with the fleet-average CO2 emission standards in §86.1818. Useful life values are specified as a given number of calendar years or miles of driving, whichever comes first.

(b) Greenhouse gas pollutants. The emission standards in §86.1818 apply for a useful life of 10 years or 120,000 miles for LDV and LLDT and 11 years or 120,000 miles for HLDT and MDPV. For non-MDPV heavy-duty vehicles, the emission standards in §86.1819 apply for a useful life of 11 years or 120,000 miles through model year 2020, and for a useful life of 15 years or 150,000 miles in model year 2021 and later. Manufacturers may certify based on the useful life as specified in paragraph (d) of this section if it is different than the useful life specified in this paragraph (b).

(c) Cold temperature emission standards. The cold temperature NMHC emission standards in §86.1811 apply for a useful life of 10 years or 120,000 miles for LDV and LLDT, and 11 years or 120,000 miles for HLDT and HDV. The cold temperature CO emission standards in §86.1811 apply for a useful life of 5 years or 50,000 miles.

(d) Criteria pollutants. The useful life provisions of this paragraph (d) apply for all emission standards not covered by paragraph (b) or (c) of this section. Except as specified in paragraph (f) of this section and in §§86.1811, 86.1813, and 86.1816, the useful life for LDT2, HLDT, MDPV, and HDV is 15 years or 150,000 miles. The useful life for LDV and LDT1 is 10 years or 120,000 miles. Manufacturers may optionally certify LDV and LDT1 to a useful life of 15 years or 150,000 miles, in which case the longer useful life would apply for all the standards and requirements covered by this paragraph (d).

(e) Intermediate useful life. Where exhaust emission standards are specified for an intermediate useful life, these standards apply for five years or 50,000 miles.

(f) Interim provisions. The useful life provisions of §86.1805-12 apply for vehicles not yet subject to Tier 3 requirements. For example, vehicles above 6,000 pounds GVWR are not subject to the useful life provisions in this section until model year 2019 unless manufacturers voluntarily certify to the Tier 3 requirements earlier than the regulations require. Also, where the transition to Tier 3 standards involves a phase-in percentage for a given standard, vehicles not included as part of the phase-in portion of the fleet continue to be subject to the useful life provisions of §86.1805-12 with respect to that standard. The useful life values for a set of vehicles may be different for exhaust and evaporative emission standards in 2021 and earlier model years; if vehicles have different useful life values for evaporative and exhaust emission standards, the evaporative useful life applies for the OBD requirements related to the leak standard and the exhaust useful life applies for all other OBD requirements.

[79 FR 23708, Apr. 28, 2014, as amended at 80 FR 9104, Feb. 19, 2015; 81 FR 73983, Oct. 25, 2016]