---
kind: "section"
citation: "40 C.F.R. § 205.51"
title: "40"
number: "205.51"
heading: "Definitions."
url: "https://uscodex.org/cfr/40/205.51"
---

# §205.51. Definitions.

- (a) As used in this subpart, all terms not defined herein shall have the meaning given them in the Act or in other subparts of this part.
  - (1) Acceptable Quality Level means the maximum percentage of failing vehicles that for purposes of sampling inspection, can be considered satisfactory as a process average.
  - (2) Acceptance of a batch means that the number of noncomplying vehicles in the batch sample is less than or equal to the acceptance number as determined by the appropriate sampling plan.
  - (3) Batch means the collection of vehicles of the same category, configuration or subgroup thereof as designated by the Administrator in a test request, from which a batch sample is to be drawn, and inspected to determine conformance with the acceptability criteria.
  - (4) Batch size means the number as designated by the Administrator in the test request of vehicles of the same category or configuration in a batch.
  - (5) Batch sample means the collection of vehicles of the same category, configuration or subgroup thereof which are drawn from a batch and from which test samples are drawn.
  - (6) Batch sample size means the number of vehicles of the same category or configuration in a batch sample.
  - (7) **Cab over axle—** or cab over engine means the cab which contains the operator/passenger compartment is directly above the engine and front axle and the entire cab can be tilted forward to permit access to the engine compartment.
  - (8) Category means a group of vehicle configurations which are identical in all material aspects with respect to the parameters listed in [§ 205.55-2](/cfr/40/205.55-2.md).
  - (9) Configuration means the basic classification unit of a manufacturer's product line and is comprised of all vehicle designs, models or series which are identical in material aspects with respect to the parameters listed in [§ 205.55-3](/cfr/40/205.55-3.md).
  - (10) Acceptance of a Batch sequence means that the number of rejected batches in the sequence is less than or equal to the acceptance number as determined by the appropriate sampling plan.
  - (11) Rejection of a Batch sequence means that the number of rejected batches in a sequence is equal to or greater than the rejection number as determined by the appropriate sampling plan.
  - (12) Capable of Transportation of Property on a street or highway means that the vehicle:
    - (i) Is self propelled and is capable of transporting any material or fixed apparatus, or is capable of drawing a trailer or semi-trailer;
    - (ii) Is capable of maintaining a cruising speed of at least 25 mph over level, paved surface;
    - (iii) Is equipped or can readily be equipped with features customarily associated with practical street or highway use, such features including but not being limited to: A reverse gear and a differential, fifth wheel, cargo platform or cargo enclosure, and
    - (iv) Does not exhibit features which render its use on a street or highway impractical, or highly unlikely, such features including, but not being limited to, tracked road means, an inordinate size or features ordinarily associated with combat or tactical vehicles.
  - (13) Exhaust System means the system comprised of a combination of components which provides for enclosed flow of exhaust gas from engine exhaust port to the atmosphere.
  - (14) **Gross Combination Weight Rating—**
    - (GCWR) means the value specified by the manufacturer as the loaded weight of a combination vehicle.
  - (15) **Gross Vehicle Weight Rating—**
    - (GVWR) means the value specified by the manufacturer as the loaded weight of a single vehicle.
  - (16) Inspection Criteria means the rejection and acceptance numbers associated with a particular sampling plan.
  - (17) Model year means the manufacturer's annual production period which includes January 1 of such calendar year: Provided, that if the manufacturer has no annual production period, the term “model year” shall mean the calendar year.
  - (18) **Noise Control System—** includes any vehicle part, component or system the primary purpose of which is to control or cause the reduction of noise emitted from a vehicle.
  - (19) Noise emission test means a test conducted pursuant to the measurement methodology specified in this subpart.
  - (20) [Reserved]
  - (21) Rejection of a batch means the number of noncomplying vehicles in the batch sample is greater than or equal to the rejection number as determined by the appropriate sampling plan.
  - (22) Shift means the regular production work period for one group of workers.
  - (23) Test sample means the collection of vehicles from the same category, configuration or subgroup thereof which is drawn from the batch sample and which will receive noise emissions tests.
  - (24) Failing vehicle means that the measured emissions of the vehicle, when measured in accordance with the applicable procedure, exceeds the applicable standard.
  - (25) Acceptance of a vehicle means that the measured emissions of the vehicle when measured in accordance with the applicable procedure, conforms to the applicable standard.
  - (26) Tampering means those acts prohibited by [section 10(a)(2)](/cfr/40/10.md?p=a-2) of the Act.
  - (27) Test sample size means the number of vehicles of the same category or configuration in a test sample.
  - (28) Test vehicle means a vehicle selected and used to demonstrate compliance with the applicable noise emission standards.
  - (29) Vehicle means any motor vehicle, machine or tractor, which is propelled by mechanical power and capable of transportation of property on a street or highway and which has a gross vehicle weight rating in excess of 10,000 pounds and a partially or fully enclosed operator's compartment.

## Notes

### Amendments

[41 FR 15544, Apr. 13, 1976, as amended at 42 FR 61456, 61458, Dec. 5, 1977; 47 FR 57714, Dec. 28, 1982]

### Authority

Authority: Secs. 6, 10, 11, 13, Pub. L. 92-574, 86 Stat. 1234 (42 U.S.C. 4905, 4909, 4910, 4912).

### Source

Source: 41 FR 15544, Apr. 13, 1976, unless otherwise noted.

### Amendments

[41 FR 15544, Apr. 13, 1976, as amended at 42 FR 61456, 61458, Dec. 5, 1977; 47 FR 57714, Dec. 28, 1982]