---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchC/part51/subpartT"
level: "subpart"
label: "Subpart T"
heading: "Conformity to State or Federal Implementation Plans of Transportation Plans, Programs, and Projects Developed, Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchC-part51-subpartT"
sections_count: 1
---

# Subpart T — Conformity to State or Federal Implementation Plans of Transportation Plans, Programs, and Projects Developed, Funded or Approved Under Title 23 U.S.C. or the Federal Transit Laws

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency › Subchapter C — Air Programs › Part 51 — Requirements for Preparation, Adoption, and Submittal of Implementation Plans

## Sections

- [§51.390. Implementation plan revision.](/cfr/40/51.390.md)