---
kind: "section"
citation: "42 U.S.C. § 16104"
title: "42"
title_heading: "The Public Health and Welfare"
number: "16104"
heading: "Reduction of engine idling"
release: "119-102"
date: "2026-07-12"
url: "https://uscodex.org/usc/42/16104"
units:
  - "Chapter 149 — National Energy Policy and Programs"
  - "Subchapter VII — Vehicles and Fuels"
  - "Part D — Miscellaneous"
---

# §16104. Reduction of engine idling

- (a) **Definitions—** In this section:
  - (1) **Administrator—** The term “[Administrator](/usc/42/15951.md?p=b-1)” means the [Administrator](/usc/42/15951.md?p=b-1) of the Environmental Protection [Agency](/usc/42/8262.md?p=1).
  - (2) **Advanced truck stop electrification system—** The term “advanced truck stop electrification system” means a [stationary](/usc/42/16121.md?p=3) system that delivers heat, air conditioning, electricity, or communications, and is capable of providing verifiable and auditable evidence of use of those services, to a heavy-duty vehicle and any occupants of the heavy-duty vehicle with or without relying on components mounted onboard the heavy-duty vehicle for delivery of those services.
  - (3) **Auxiliary power unit—** The term “auxiliary power unit” means an integrated system that—
    - (A) provides heat, air conditioning, engine warming, or electricity to components on a heavy-duty vehicle; and
    - (B) is certified by the [Administrator](/usc/42/15951.md?p=b-1) under part 89 of title 40, Code of Federal Regulations (or any successor regulation), as meeting applicable emission standards.
  - (4) **Heavy-duty vehicle—** The term “heavy-duty vehicle” means a vehicle that—
    - (A) has a gross vehicle weight rating greater than 8,500 pounds; and
    - (B) is powered by a diesel engine.
  - (5) **Idle reduction technology—** The term “idle reduction technology” means an advanced truck stop electrification system, auxiliary power unit, or other technology that—
    - (A) is used to reduce long-duration idling; and
    - (B) allows for the main drive engine or auxiliary refrigeration engine to be shut down.
  - (6) **Energy conservation technology—** the[^1] term “energy conservation technology” means any device, system of devices, or equipment that improves the fuel economy.
  - (7) **Long-duration idling—**
    - (A) **In general—** The term “long-duration idling” means the operation of a main drive engine or auxiliary refrigeration engine, for a period greater than 15 consecutive minutes, at a time at which the main drive engine is not engaged in gear.
    - (B) **Exclusions—** The term “long-duration idling” does not include the operation of a main drive engine or auxiliary refrigeration engine during a routine stoppage associated with traffic movement or congestion.
- (b) **Idle reduction technology benefits, programs, and studies—**
  - (1) **In general—** Not later than 90 days after August 8, 2005, the [Administrator](/usc/42/15951.md?p=b-1) shall—
    - (A)
      - (i) commence a review of the mobile source air emission models of the Environmental Protection [Agency](/usc/42/8262.md?p=1) used under the Clean Air Act ([42 U.S.C. 7401](/usc/42/7401.md) et seq.) to determine whether the models accurately reflect the emissions resulting from long-duration idling of heavy-duty vehicles and other vehicles and engines; and
      - (ii) update those models as the [Administrator](/usc/42/15951.md?p=b-1) determines to be appropriate; and
    - (B)
      - (i) commence a review of the emission reductions achieved by the use of idle reduction technology; and
      - (ii) complete such revisions of the regulations and guidance of the Environmental Protection [Agency](/usc/42/8262.md?p=1) as the [Administrator](/usc/42/15951.md?p=b-1) determines to be appropriate.
  - (2) **Deadline for completion—** Not later than 180 days after August 8, 2005, the [Administrator](/usc/42/15951.md?p=b-1) shall—
    - (A) complete the reviews under subparagraphs [(A)(i)](#b-1-A-i) and [(B)(i)](#b-1-B-i) of paragraph (1); and
    - (B) prepare and make publicly available one or more reports on the results of the reviews.
  - (3) **Discretionary inclusions—** The reviews under subparagraphs [(A)(i)](#b-1-A-i) and [(B)(i)](#b-1-B-i) of paragraph (1) and the reports under [paragraph (2)(B)](#b-2-B) may address the potential fuel savings resulting from use of idle reduction technology.
  - (4) **Idle reduction and energy conservation deployment program—**
    - (A) **Establishment—**
      - (i) **In general—** Not later than 90 days after August 8, 2005, the [Administrator](/usc/42/15951.md?p=b-1), in consultation with the [Secretary](/usc/42/15801.md?p=4) of Transportation shall, through the Environmental Protection [Agency](/usc/42/8262.md?p=1)’s SmartWay Transport Partnership, establish a program to support deployment of idle reduction and energy conservation technologies.
      - (ii) **Priority—** The [Administrator](/usc/42/15951.md?p=b-1) shall give priority to the deployment of idle reduction and energy conservation technologies based on the costs and beneficial effects on air quality and ability to lessen the emission of criteria air pollutants.
    - (B) **Funding—**
      - (i) **Authorization of appropriations—** There are authorized to be appropriated to the [Administrator](/usc/42/15951.md?p=b-1) to carry out [subparagraph (A)](#b-4-A) for the purpose of reducing extended idling from heavy-duty vehicles $19,500,000 for fiscal year 2006, $30,000,000 for fiscal year 2007, and $45,000,000 for fiscal year 2008.
      - (ii) **Locomotives—** There are authorized to be appropriated to the [administrator](/usc/42/15951.md?p=b-1) to carry out [subparagraph (A)](#b-4-A) for the purpose of reducing extended idling from locomotives $10,000,000 for fiscal year 2006, $15,000,000 for fiscal year 2007, and $20,000,000 for fiscal year 2008.
      - (iii) **Cost sharing—** Subject to [clause (iv)](#b-4-B-iv), the [Administrator](/usc/42/15951.md?p=b-1) shall require at least 50 percent of the costs directly and specifically related to any [project](/usc/42/16371.md?p=12) under this section to be provided from non-Federal sources.
      - (iv) **Necessary and appropriate reductions—** The [Administrator](/usc/42/15951.md?p=b-1) may reduce the non-Federal requirement under [clause (iii)](#b-4-B-iii) if the [Administrator](/usc/42/15951.md?p=b-1) determines that the reduction is necessary and appropriate to meet the objectives of this section.
  - (5) **Idling location study—**
    - (A) **In general—** Not later than 90 days after August 8, 2005, the [Administrator](/usc/42/15951.md?p=b-1), in consultation with the [Secretary](/usc/42/15801.md?p=4) of Transportation, shall commence a study to analyze all locations at which heavy-duty vehicles stop for long-duration idling, including—
      - (i) truck stops;
      - (ii) rest areas;
      - (iii) border crossings;
      - (iv) ports;
      - (v) transfer facilities; and
      - (vi) private terminals.
    - (B) **Deadline for completion—** Not later than 180 days after August 8, 2005, the [Administrator](/usc/42/15951.md?p=b-1) shall—
      - (i) complete the study under [subparagraph (A)](#b-5-A); and
      - (ii) prepare and make publicly available one or more reports of the results of the study.
- (c) **Omitted—**
- (d) **Report—** Not later than 60 days after the date on which funds are initially awarded under this section, and on an annual basis thereafter, the [Administrator](/usc/42/15951.md?p=b-1) shall submit to Congress a report containing—
  - (1) an identification of the grant recipients, a description of the [projects](/usc/42/16371.md?p=12) to be funded and the amount of funding provided; and
  - (2) an identification of all other applicants that submitted applications under the program.

## Footnotes

[^1]: So in original. Probably should be capitalized.

## Source credit

(Pub. L. 109–58, title VII, § 756, Aug. 8, 2005, 119 Stat. 829.)

## Notes

### Editorial Notes

### References in Text

The Clean Air Act, referred to in subsec. (b)(1)(A)(i), is act July 14, 1955, ch. 360, 69 Stat. 322, which is classified generally to chapter 85 (§ 7401 et seq.) of this title. For complete classification of this Act to the Code, see Short Title note set out under section 7401 of this title and Tables.

### Codification

Section is comprised of section 756 of Pub. L. 109–58. Subsec. (c) of section 756 of Pub. L. 109–58 amended section 127 of Title 23, Highways.