40 CFR § 1037.670 - Optional CO emission standards for tractors at or above 120,000 pounds GCWR.

---
identifier: "/us/cfr/t40/s1037.670"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 1037.670 - Optional CO emission standards for tractors at or above 120,000 pounds GCWR."
title_number: 40
title_name: "Protection of Environment"
section_number: "1037.670"
section_name: "Optional CO emission standards for tractors at or above 120,000 pounds GCWR."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "U"
subchapter_name: "AIR POLLUTION CONTROLS"
part_number: "1037"
part_name: "CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401—7671q."
regulatory_source: "81 FR 74048, Oct. 25, 2016, unless otherwise noted."
cfr_part: "1037"
---


# 1037.670 Optional CO emission standards for tractors at or above 120,000 pounds GCWR.

(a) You may certify model year 2026 and earlier tractors at or above 120,000 pounds GCWR to the following CO<sub>2</sub> standards instead of the Phase 2 CO<sub>2</sub> standards of § 1037.106:

Table 1 of Paragraph (**a**) of § 1037.670—Optional CO Standards for Tractors Above 120,000 Pounds GCWR

[g/ton-mile]

| Subcategory | Model years2021-2023 | Model years2024-2026 |
| --- | --- | --- |
| Heavy Class 8 Low-Roof Day Cab | 53.5 | 50.8 |
| Heavy Class 8 Low-Roof Sleeper Cab | 47.1 | 44.5 |
| Heavy Class 8 Mid-Roof Day Cab | 55.6 | 52.8 |
| Heavy Class 8 Mid-Roof Sleeper Cab | 49.6 | 46.9 |
| Heavy Class 8 High-Roof Day Cab | 54.5 | 51.4 |
| Heavy Class 8 High-Roof Sleeper Cab | 47.1 | 44.2 |
| Note that these standards are not directly comparable to the standards for Heavy-Haul Tractors in § 1037.106 because GEM handles aerodynamic performance differently for the two sets of standards. |  |  |

(b) Determine subcategories as described in § 1037.230 for tractors that are not heavy-haul tractors. For example, the subcategory for tractors that would otherwise be considered Class 8 low-roof day cabs would be Heavy Class 8 Low-Roof Day Cabs and would be identified as HC8__DC__LR for the GEM run.

(c) Except for the CO<sub>2</sub> standards of § 1037.106, all provisions applicable to tractors under this part continue to apply to tractors certified to the standards of this section. Include the following compliance statement on your label instead of the statement specified in § 1037.135(c)(8): “THIS VEHICLE COMPLIES WITH U.S. EPA REGULATIONS FOR [MODEL YEAR] HEAVY-DUTY VEHICLES UNDER 40 CFR 1037.670.”

(d) The optional emission standards in this section are intended primarily for tractors that will be exported; however, you may include any tractors certified under this section in your emission credit calculation under § 1037.705 if they are part of your U.S.-directed production volume.

[81 FR 74048, Oct. 25, 2016, as amended at 86 FR 34491, June 29, 2021; 89 FR 29789, Apr. 22, 2024]