---
kind: "section"
citation: "40 C.F.R. § 86.001-2"
title: "40"
number: "86.001-2"
heading: "Definitions."
url: "https://uscodex.org/cfr/40/86.001-2"
---

# §86.001-2. Definitions.


The definitions of [§ 86.000-2](/cfr/40/86.000-2.md) continue to apply to 2000 and later model year vehicles. The definitions listed in this section apply beginning with the 2001 model year.

Useful life means:

- (1) For light-duty vehicles, and for light light-duty trucks not subject to the Tier 0 standards of [§ 86.094-9(a)](/cfr/40/86.094-9.md?p=a), intermediate useful life and/or full useful life. Intermediate useful life is a period of use of 5 years or 50,000 miles, whichever occurs first. Full useful life is a period of use of 10 years or 100,000 miles, whichever occurs first, except as otherwise noted in [§ 86.094-9](/cfr/40/86.094-9.md). The useful life of evaporative and/or refueling emission control systems on the portion of these vehicles subject to the evaporative emission test requirements of [§ 86.130-96](/cfr/40/86.130-96.md), and/or the refueling emission test requirements of [§ 86.151-2001](/cfr/40/86.151-2001.md), is defined as a period of use of 10 years or 100,000 miles, whichever occurs first.
- (2) For light light-duty trucks subject to the Tier 0 standards of [§ 86.094-9(a)](/cfr/40/86.094-9.md?p=a), and for heavy light-duty truck engine families, intermediate and/or full useful life. Intermediate useful life is a period of use of 5 years or 50,000 miles, whichever occurs first. Full useful life is a period of use of 11 years or 120,000 miles, whichever occurs first. The useful life of evaporative emission and/or refueling control systems on the portion of these vehicles subject to the evaporative emission test requirements of [§ 86.130-96](/cfr/40/86.130-96.md), and/or the refueling emission test requirements of [§ 86.151-2001](/cfr/40/86.151-2001.md), is also defined as a period of 11 years or 120,000 miles, whichever occurs first.
- (3) **For an Otto-cycle heavy-duty engine family—**
  - (i) For hydrocarbon and carbon monoxide standards, a period of use of 8 years or 110,000 miles, whichever first occurs.
  - (ii) For the oxides of nitrogen standard, a period of use of 10 years or 110,000 miles, whichever first occurs.
  - (iii) For the portion of evaporative emission control systems subject to the evaporative emission test requirements of [§ 86.1230-96](/cfr/40/86.1230-96.md), a period of use of 10 years or 110,000 miles, whichever occurs first.
- (4) **For a diesel heavy-duty engine family—**
  - (i) For light heavy-duty diesel engines, for hydrocarbon, carbon monoxide, and particulate standards, a period of use of 8 years or 110,000 miles, whichever first occurs.
  - (ii) For light heavy-duty diesel engines, for the oxides of nitrogen standard, a period of use of 10 years or 110,000 miles, whichever first occurs.
  - (iii) For medium heavy-duty diesel engines, for hydrocarbon, carbon monoxide, and particulate standards, a period of use of 8 years or 185,000 miles, whichever first occurs.
  - (iv) For medium heavy-duty diesel engines, for the oxides of nitrogen standard, a period of use of 10 years or 185,000 miles, whichever first occurs.
  - (v) For heavy heavy-duty diesel engines, for hydrocarbon, carbon monoxide, and particulate standards, a period of use of 8 years or 290,000 miles, whichever first occurs, except as provided in [paragraph (4)(vii)](#4-vii) of this definition.
  - (vi) For heavy heavy-duty diesel engines, for the oxides of nitrogen standard, a period of use of 10 years or 290,000 miles, whichever first occurs.
  - (vii) For heavy heavy-duty diesel engines used in urban buses, for the particulate standard, a period of use of 10 years or 290,000 miles, whichever first occurs.

## Notes

### Amendments

[59 FR 16281, Apr. 6, 1994, as amended at 61 FR 54886, Oct. 22, 1996]

### Source

Source: 42 FR 32907, June 28, 1977, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401-7671q.

### Amendments

[59 FR 16281, Apr. 6, 1994, as amended at 61 FR 54886, Oct. 22, 1996]