# Revisions to In-Use Testing for Heavy-Duty Diesel Engines and Vehicles; Emissions Measurement and Instrumentation; Not-to-Exceed Emission Standards; and Technical Amendments for Off-Highway Engines
> **Rule** · Direct final rule. · Published 2010-11-08 · Effective 2011-01-07 · 75 FR 68448
## Document
- **Document number:** 2010-27892
- **Category:** air-emissions
- **Federal Register citation:** 75 FR 68448
- **CFR reference:** 40 CFR 86
- **Publication date:** 2010-11-08
- **Effective date:** 2011-01-07
- **EPA docket:** EPA-HQ-OAR-2010-0142
## Abstract

EPA is taking direct final action on several revisions to EPA's mobile source emission programs standards and test procedures. EPA believes that each of these is minor and non-controversial in nature. Most of the changes arise from the results of the collaborative test program and related technical work we conducted for the highway heavy-duty diesel in-use testing program. Most noteworthy here is the adoption of a particulate matter measurement allowance for use with portable emission measurement systems. Related to this are two provisions to align the in-use program timing requirements with completion of the program as required in current regulations and the incorporation of revisions to a few technical requirements in the testing regulations based on information learned in this and one other test program. Finally, the DFR modifies a few transitional flexibilities for locomotive, recreational marine, and Tier 4 nonroad engines and incorporates a handful of minor corrections.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2010/11/08/2010-27892/revisions-to-in-use-testing-for-heavy-duty-diesel-engines-and-vehicles-emissions-measurement-and)
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