---
type: "Bill"
title: "Vehicle emissions."
description: "Requires IDEM to: (1) perform a comprehensive evaluation of ambient air quality within nonattainment areas in Indiana; and (2) identify air pollution reduction or regulatory relief strategies that could accomplish certain goals with respect to the federal Clean Air Act."
jurisdiction: "us/states/in"
legislature: "Indiana General Assembly"
session: "2025"
identifier: "SB 103"
citation: "Indiana SB 103 (2025)"
classification: ["bill"]
subjects: ["AGENCIES; Department of Environmental Management (IDEM)", "COUNTIES; Lake", "COUNTIES; Porter", "ENVIRONMENT; Air Pollution", "FEDERAL GOVERNMENT; Generally", "GENERAL ASSEMBLY; Legislative Services Agency", "SENIOR CITIZENS", "STATE ELECTED OFFICIALS; Governor", "TRANSPORTATION; Landcraft"]
status: "enacted"
primary_sponsors: ["Dan Dernulc", "Harold Slager", "Rick Niemeyer"]
version_count: 4
action_count: 27
vote_count: 3
first_action: "2025-01-08"
last_action: "2025-05-06"
source: "openstates"
source_identifier: "ocd-bill/9fd4e395-5334-427c-82dd-2fb02d091241"
source_url: "https://api.iga.in.gov/2025/bills/sb0103"
source_hash: "4ed8c6d7ba220402466f9ffbd4b37d731b3dc963b015170923a4d4ad0d5ed40e"
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-in"]
---

# Indiana SB 103 (2025) — Vehicle emissions.

Requires IDEM to: (1) perform a comprehensive evaluation of ambient air quality within nonattainment areas in Indiana; and (2) identify air pollution reduction or regulatory relief strategies that could accomplish certain goals with respect to the federal Clean Air Act.

## Version chain

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

1. **Engrossed Senate Bill (H)** (committee substitute) — [source](https://iga.in.gov/pdf-documents/124/2025/senate/bills/SB0103/SB0103.03.ENGS.pdf)
2. **Enrolled Senate Bill (S)** (committee substitute) — [source](https://iga.in.gov/pdf-documents/124/2025/senate/bills/SB0103/SB0103.05.ENRH.pdf)
3. **Introduced Senate Bill (S)** (committee substitute) — [source](https://iga.in.gov/pdf-documents/124/2025/senate/bills/SB0103/SB0103.01.INTR.pdf)
4. **Senate Bill (S)** (committee substitute) — [source](https://iga.in.gov/pdf-documents/124/2025/senate/bills/SB0103/SB0103.04.COMH.pdf)

## Votes

- SB 103 - Slager - 3rd Reading — **91–1** (pass) · lower
- SB 103 - Niemeyer — **49–0** (pass) · upper
- SB 103 - Niemeyer - 3rd Reading — **47–0** (pass) · upper

## Sponsors

- Dan Dernulc — primary (person)
- Harold Slager — primary (person)
- Rick Niemeyer — primary (person)
- Eric Bassler — coauthor (person)
- Julie Olthoff — cosponsor (person)
- Lonnie Randolph — coauthor (person)
- Mike Andrade — cosponsor (person)
- Mike Aylesworth — cosponsor (person)
- Rodney Pol — coauthor (person)

## Timeline

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

- **2025-01-08** Authored by Senator Niemeyer
- **2025-01-08** First reading: referred to Committee on Environmental Affairs `reading-1, referral-committee`
- **2025-01-27** Committee report: do pass, adopted `committee-passage`
- **2025-01-27** Senator Dernulc added as second author
- **2025-01-30** Senator Bassler added as coauthor
- **2025-01-30** Second reading: ordered engrossed `reading-2`
- **2025-01-30** Senator Randolph added as coauthor
- **2025-02-04** Placed back on second reading
- **2025-02-13** Reread second time: amended, ordered engrossed `reading-2`
- **2025-02-13** Amendment #1 (Niemeyer) prevailed; voice vote `amendment-passage`
- **2025-02-17** House sponsor: Representative Slager
- **2025-02-17** Third reading: passed; Roll Call 135: yeas 47, nays 0 `passage, reading-3, reading-3`
- **2025-02-17** Cosponsors: Representatives Olthoff, Aylesworth, Andrade
- **2025-02-17** Senator Pol added as coauthor
- **2025-02-18** Referred to the House `referral`
- **2025-03-03** First reading: referred to Committee on Environmental Affairs `reading-1, referral-committee`
- **2025-04-03** Committee report: amend do pass, adopted `committee-passage`
- **2025-04-07** Second reading: ordered engrossed `reading-2`
- **2025-04-08** Third reading: passed; Roll Call 392: yeas 91, nays 1 `passage, reading-3, reading-3`
- **2025-04-09** Motion to concur filed `filing`
- **2025-04-09** Returned to the Senate with amendments `receipt`
- **2025-04-22** Senate concurred with House amendments; Roll Call 479: yeas 49, nays 0
- **2025-04-23** Signed by the President Pro Tempore `passage`
- **2025-04-23** Signed by the Speaker `passage`
- **2025-05-06** Signed by the Governor `executive-signature`
- **2025-04-29** Signed by the President of the Senate `passage`
- **2025-05-06** Public Law 187 `became-law`

## Source

OpenStates / OpenCivicData bulk snapshot [2026-07-01](https://data.openstates.org/daily/2026-07-01/public.pgdump); origin `ocd-bill/9fd4e395-5334-427c-82dd-2fb02d091241`. Confidence: reported (aggregated from official Indiana legislature records).