---
type: "Bill"
title: "TO CREATE THE ARKANSAS DIESEL ENGINE FREEDOM ACT OF 2025; AND TO PROHIBIT STATE ENFORCEMENT OF FEDERAL REGULATION OF CERTAIN TYPES OF DIESEL ENGINES."
description: "TO CREATE THE ARKANSAS DIESEL ENGINE FREEDOM ACT OF 2025; AND TO PROHIBIT STATE ENFORCEMENT OF FEDERAL REGULATION OF CERTAIN TYPES OF DIESEL ENGINES."
jurisdiction: "us/states/ar"
legislature: "Arkansas Legislature"
session: "2025"
identifier: "SB 478"
citation: "Arkansas SB 478 (2025)"
classification: ["bill"]
subjects: []
status: "enacted"
primary_sponsors: ["G. Stubblefield"]
version_count: 2
action_count: 15
vote_count: 0
first_action: "2025-03-17T19:37:04+00:00"
last_action: "2025-04-18T21:11:31+00:00"
source: "openstates"
source_identifier: "ocd-bill/bd1f9ac9-6b45-42bf-a218-5bd704ecd84a"
source_url: "https://www.arkleg.state.ar.us/Bills/FTPDocument/?path=%2fSessionInformation%2LegislativeMeasures.txt"
source_hash: "adc5976f43e801f3958e6644c9e460417e57d5ca997aa3a040fd0a35230c93f3"
vintage: "2026-07-01"
source_snapshot: "https://data.openstates.org/daily/2026-07-01/public.pgdump"
retrieved_at: "2026-07-06"
confidence: "reported"
tags: ["legislation", "bill", "us-ar"]
---

# Arkansas SB 478 (2025) — TO CREATE THE ARKANSAS DIESEL ENGINE FREEDOM ACT OF 2025; AND TO PROHIBIT STATE ENFORCEMENT OF FEDERAL REGULATION OF CERTAIN TYPES OF DIESEL ENGINES.

## Version chain

The bill's text revisions, in order — the diff chain from filing to enrollment.

1. **Act 738** (committee substitute) — [source](https://www.arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2025R%2FPublic%2F&file=738.pdf&ddBienniumSession=2025%2F2025R)
2. **SB 478** (committee substitute) — [source](https://www.arkleg.state.ar.us/assembly/2025/2025R/Bills/SB478.pdf)

## Sponsors

- G. Stubblefield — primary (person)

## Timeline

The legislative action history — every referral, reading, and vote.

- **2025-03-17T19:37:04+00:00** Filed `introduction`
- **2025-03-17T21:23:48+00:00** Read first time, rules suspended, read second time, referred to TRANSPORTATION, TECHNOLOGY & LEGISLATIVE AFFAIRS - SENATE `reading-1, referral-committee`
- **2025-04-08T01:19:39+00:00** Returned by the Committee, with the recommendation that it Do Pass `committee-passage-favorable`
- **2025-04-08T23:41:21+00:00** Read the third time and passed. `passage, reading-3`
- **2025-04-08T23:41:38+00:00** Ordered immediately transmitted to the House.
- **2025-04-09T00:06:36+00:00** RECEIVED FROM THE SENATE
- **2025-04-09T01:49:20+00:00** Read the first time, rules suspended, read the second time and referred to the Committee on PUBLIC TRANSPORTATION- HOUSE `reading-1, reading-2, referral-committee`
- **2025-04-09T16:39:23+00:00** Returned by the Committee Do Pass `committee-passage`
- **2025-04-14T22:15:19+00:00** Read the third time and passed and ordered transmitted to the Senate. `passage, reading-3`
- **2025-04-14T22:15:35+00:00** Returned to the Senate as passed.
- **2025-04-15T01:47:17+00:00** Returned from the House as passed.
- **2025-04-15T01:47:22+00:00** ORDERED ENROLLED
- **2025-04-15T14:06:34+00:00** Reported correctly enrolled and ordered delivered to the Governor.
- **2025-04-15T14:06:38+00:00** DELIVERED TO GOVERNOR. `executive-receipt`
- **2025-04-18T21:11:31+00:00** Notification that SB478 is now Act 738 `executive-signature`

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/bd1f9ac9-6b45-42bf-a218-5bd704ecd84a`. Confidence: reported (aggregated from official Arkansas legislature records).