(a) Applicability and general provisions. This section describes Tier 3 exhaust emission standards for complete heavy-duty vehicles. These standards are optional for incomplete heavy-duty vehicles and for heavy-duty vehicles above 14,000 pounds GVWR as described in § 86.1801. Greenhouse gas emission standards are specified in § 86.1818 for MDPV and in § 86.1819 for other HDV. See § 86.1813 for evaporative and refueling emission standards. This section starts to apply in model year 2018, except that the provisions may apply to vehicles before model year 2018 as specified in paragraph (b)(11) of this section. This section applies for model year 2027 and later vehicles only as specified in § 86.1811-27. Separate requirements apply for MDPV as specified in § 86.1811. See subpart A of this part for requirements that apply for incomplete heavy-duty vehicles and for heavy-duty engines certified independent of the chassis. The following general provisions apply:

(1) Test all vehicles as described in this section using a chassis dynamometer; establish appropriate load settings based on adjusted loaded vehicle weight (see § 86.1803).

(2) Some provisions apply differently depending on the vehicle's power-to-weight ratio. Determine a vehicle's power-to-weight ratio by dividing the engine's rated power by the vehicle's GVWR (in hp/pound). For purposes of this section, if a test group includes multiple configurations, use the vehicle with the highest power-to-weight ratio to characterize the test group.

(3) Use E10 test fuel as required in § 86.113, except as specified in this section.

(4) Measure emissions from hybrid electric vehicles (including plug-in hybrid electric vehicles) as described in 40 CFR part 1066, subpart F, except that these procedures do not apply for plug-in hybrid electric vehicles during charge-depleting operation.

(b) Tier 3 exhaust emission standards. Exhaust emissions may not exceed the Tier 3 exhaust emission standards, as follows:

(1) Measure emissions using the procedures of subpart B of this part, using specific driving schedules and additional procedures as follows:

(i) The Federal Test Procedure (FTP) is based on testing with the Urban Dynamometer Driving Schedule (UDDS) specified in paragraph (a) of Appendix I of this part.

(ii) The Heavy-Duty Supplemental Federal Test Procedure (HD-SFTP) involves testing with the UDDS, the SC03 driving schedule specified in paragraph (h) of Appendix I of this part, and one of the following additional driving schedules:

(A) For Class 2b vehicles, the US06 driving schedule specified in paragraph (g) of Appendix I of this part.

(B) For Class 2b vehicles with a power-to-weight ratio at or below 0.024 hp/pound that are certified to optional standards under paragraphs (b)(2) and (4) of this section, the highway portion of the US06 driving schedule characterized as the “second bag” in § 86.159-08(a).

(C) For Class 3 vehicles, the Hot LA-92 driving schedule as specified in paragraph (c) of Appendix I of this part.

(iii) HD-SFTP emissions are calculated as a composite of test results over these driving schedules based on the following calculation:

HD-SFTP (g/mi) = 0.35·FTP + 0.28·HDSIM + 0.37·SC03 Where: HDSIM = the appropriate driving schedule specified in paragraph (b)(1)(ii)(A) through (C) of this section.

(iv) You may alternatively use FTP emission results to substitute for the SC03 value in the calculation under paragraph (b)(1)(iii) of this section for a given vehicle for any testing under this section. Such vehicles remain subject to the SFTP standard when tested over the SC03 driving schedule.

(v) Hydrocarbon emission standards are expressed as NMOG; however, you may measure exhaust emissions based on nonmethane hydrocarbon instead of NMOG as described in 40 CFR 1066.635.

(2) Table 1 of this section describes fully phased-in Tier 3 standards that apply as specified in this paragraph (b) for the identified driving schedules. The FTP standards for NMOG + NOX apply on a fleet-average basis using discrete bin standards as described in paragraph (b)(4) of this section. The bin standards include additional emission standards for CO emissions, and for NMOG + NOX standards when testing over the HD-SFTP driving schedule. Table 1 follows:

(3) The FTP standards specified in this section apply equally for testing at low-altitude conditions and high-altitude conditions. The HD-SFTP standards described in this section apply only for testing at low-altitude conditions.

(4) The FTP emission standard for NMOG + NOX is based on a fleet average in a given model year. You must specify a family emission limit (FEL) for each test group. The FEL serves as the emission standard for the test group with respect to all required FTP testing. Calculate your fleet-average emission level as described in § 86.1860 to show that you meet the specified standard. For multi-fueled vehicles, calculate fleet-average emission levels based only on emission levels for testing with gasoline or diesel fuel. You may generate or use emission credits for banking and trading and you may use banked or traded credits for demonstrating compliance with the FTP emission standard for NMOG + NOX as described in § 86.1861. You comply with the emission standard for a given model year if you have enough credits to show that your fleet-average emission level is at or below the applicable standard. You may exchange credits between or among any test groups subject to standards under this section. Specify one of the identified values from Table 2 or Table 3 of this section as the FEL for demonstrating that your fleet-average emission level complies with the FTP emission standard for NMOG + NOX. These FEL values define emission bins that also determine corresponding emission standards for NMOG + NOX emissions over the HD-SFTP driving schedule and for CO emissions, as follows:

(5) [Reserved]

(6) The full Tier 3 program includes new emission standards for NMOG + NOX, PM, CO, and formaldehyde; it also includes measurement with a new test fuel and a longer useful life. Vehicles meeting all these requirements are considered Final Tier 3 vehicles. Vehicles that do not meet all the Tier 3 requirements are considered Interim Tier 3 vehicles. The Tier 3 PM standards phase in over several years. Any vehicles not subject to Tier 3 PM standards during the phase-in period must continue to comply with the PM standards in § 86.1816-08. Paragraph (b)(7) of this section describes how to transition to Tier 3 standards for emissions other than PM. The following provisions describe the primary approach for phasing in the Tier 3 PM standards:

(i) You must meet the FTP emission standard for PM with 20, 40, 70, and 100 percent of your projected nationwide sales of all vehicles subject to this section in model years 2018 through 2021, respectively. Each vehicle meeting the Tier 3 FTP standard for PM must also meet the Tier 3 HD-SFTP standard for PM.

(ii) You may disregard the phase-in percentages specified in paragraph (b)(6)(i) of this section if you instead comply with an indexed PM phase-in schedule as described in this paragraph (b)(6)(ii). To do this, you must notify us of your intent before January 1, 2018, and include a detailed plan for complying with the indexed phase-in schedule. You comply with the indexed phase-in schedule by calculating a PM phase-in index at or above 440 using the following equation for model years 2018 through 2021:

PM phase-in index = 4·APP2018 + 3·APP2019 + 2·APP2020 + APP2021 Where: APP = The phase-in percentage of vehicles meeting the Tier 3 PM standards for the indicated model year, based on actual sales.

(iii) Vehicles meeting the Tier 3 PM standards must meet those standards over the useful life as specified in § 86.1805. Note that Interim Tier 3 vehicles may have different useful life values for PM emission standards than for other emission standards.

(iv) Measure PM emissions from all vehicles using the same test fuel used for measuring NMOG + NOX emissions.

(v) You may certify Interim Tier 3 vehicles based on carryover data.

(vi) You may use the alternative phase-in provisions described in paragraph (b)(8) of this section to transition to the Tier 3 exhaust emission standards on a different schedule.

(7) The following provisions describe the primary approach for phasing in the Tier 3 standards other than PM in 2022 and earlier model years:

(i) The fleet-average FTP emission standard for NMOG + NOX phases in over several years as described in this paragraph (b)(7)(i). You must identify FELs as described in paragraph (b)(4) of this section and calculate a fleet-average emission level to show that you meet the FTP emission standard for NMOG+NOX that applies for each model year. You may certify using transitional bin standards specified in Table 5 of this section through model year 2021; these vehicles are subject to the FTP emission standard for formaldehyde as described in § 86.1816-08. You may use the E0 test fuel specified in § 86.113 for gasoline-fueled vehicles certified to the transitional bins; the useful life period for these vehicles is 120,000 miles or 11 years. Fleet-average FTP emission standards decrease as shown in the following table:

(ii) You may use the alternative phase-in provisions described in paragraph (b)(8) of this section to transition to the Tier 3 exhaust emission standards on a different schedule.

(8) This paragraph (b)(8) describes an alternative approach to phasing in the Tier 3 emission standards. If you choose this approach, you must phase in the Tier 3 standards for all your vehicles subject to this section according to this schedule. Under this alternative phase in, you must meet all the standards specified in paragraph (b)(2) of this section according to the phase-in schedule specified in Table 6 of this section based on the indicated percentage of your projected nationwide sales in each model year. These vehicles must meet the applicable FTP emission standard for CO and the HD-SFTP emission standards for NMOG + NOX and CO that apply for Class 2b Bin 170 and Class 3 Bin 230 as described in paragraph (b)(4) of this section. Any vehicles not subject to Tier 3 standards during the phase-in period must continue to comply with the gaseous exhaust emission standards in § 86.1816-08. Each vehicle counting toward the PM phase-in percentage under this paragraph (b)(8) in model years 2019 and 2020 must also be included in the portion of the fleet meeting the Tier 3 standards for pollutants other than PM. Each vehicle counting toward the phase-in percentage for any pollutant must use the Tier 3 test fuel specified in § 86.113-15. The following exceptions and special provisions apply under this paragraph (b)(8):

(i) For model year 2019, you may exclude from the phase-in calculation any test groups that have a Job 1 date on or before March 3, 2018 (see 40 CFR 85.2304).

(ii) You may generate Tier 3 emission credits during the phase-in period if all your pre-Tier 3 vehicles in a given model year have FELs at or below the NOX and NMHC standards in § 86.1816-08. Determine emission credits by calculating fleet-average emission levels for Tier 3 and pre-Tier 3 vehicles together; for pre-Tier 3 vehicles use an NMOG + NOX equivalent FEL of 0.395 g/mile for Class 2b vehicles and 0.630 g/mile for Class 3 vehicles.

(9) Except as specified in paragraph (b)(8) of this section, you may not use credits generated from vehicles certified under § 86.1816-08 for demonstrating compliance with the Tier 3 standards.

(10) [Reserved]

(11) You may voluntarily certify your vehicles under this section in model years 2016 and 2017. If you do this, the fleet-average FTP emission standards for NMOG + NOX apply to all your heavy-duty vehicles under this section as specified in paragraph (b)(7)(i) of this section. Use any of the available bin standards as described in this section. Vehicles certified under this paragraph (b)(11) must comply with the PM standards specified in § 86.1816-08 instead of the Tier 3 PM standards specified in this section.

(12) Alternate standards apply for in-use testing with 2022 and earlier model year vehicles as described in this paragraph (b)(12). These alternate standards apply in the first model year that a test group is certified to Tier 3 FTP or HD-SFTP standards for NMOG + NOX or PM under this section. The alternate in-use standards also apply in the following model year (but not beyond 2022) for carryover test groups certified to the same bin standards. If you certify a test group to more stringent bin standards under this section in a given model year, the alternate in-use standards apply as if that were the first model year of certifying to the Tier 3 standards. The provisions of this section apply separately for NMOG + NOX and PM. This paragraph (b)(12) does not apply for Bin 0 vehicles.

(i) The alternate in-use FTP standards for PM are 0.016 g/mile for Class 2b vehicles and 0.020 g/mile for Class 3 vehicles.

(ii) The alternate in-use HD-SFTP standards for PM are 0.012 g/mile for Class 2b vehicles with a power-to-weight ratio at or below 0.024 hp/pound that are certified to optional standards under paragraphs (b)(2) and (4) of this section, and 0.015 g/mile for other Class 2b vehicles. The alternate in-use HD-SFTP standard for PM is 0.012 g/mile for Class 3 vehicles. Alternate in-use HD-SFTP standards do not apply for vehicles certified to the transitional bins described in paragraph (b)(7) of this section.

(iii) Alternate in-use FTP and HD-SFTP standards for NMOG + NOX apply as specified in the following table:

(13) Keep records as needed to show that you meet the requirements specified in this paragraph (b) for phasing in standards and for complying with declining fleet-average average standards.

(14) Starting in model year 2027, you may certify vehicles using the following transitional Tier 4 bins as part of the compliance demonstration for meeting the Tier 4 declining fleet average NMOG+NOX standard in § 86.1811-27(b)(6):

(c) Highway NMOG + NOX exhaust emission standard. For vehicles certified to any of the Tier 3 standards specified in paragraph (b) of this section, NMOG + NOX emissions measured on the highway test cycle in 40 CFR 1066.840 may not exceed the applicable NMOG + NOX bin standard for FTP testing. Demonstrate compliance with this standard for low-mileage vehicles by applying the appropriate deterioration factor.

(d) Provisions for Otto-cycle engines. The special provisions described in § 86.1811-17(d) apply to vehicles with Otto-cycle engines that are certified under this section.

(e) Small-volume manufacturers. Small-volume manufacturers meeting the eligibility requirements in § 86.1838 may delay complying with the requirements in this section until model year 2022. This also applies for continuing to use the E0 test fuel specified in § 86.113 through model year 2021. If meeting the Tier 3 standards would cause severe economic hardship, such manufacturers may ask us to approve an extended compliance deadline under the provisions of 40 CFR 1068.250, except that the solvency criterion does not apply and there is no maximum duration of the hardship relief.

[79 FR 23721, Apr. 28, 2014, as amended at 80 FR 9108, Feb. 19, 2015; 81 FR 73984, Oct. 25, 2016; 89 FR 28168, Apr. 18, 2024]