UVM researchers brief Senate Transportation on nationwide vehicle inspection and emissions rules

BURLINGTON, Vt. — Student researchers from the University of Vermont Legislative Research Service presented a statewide review of motor-vehicle safety and emissions inspection laws to the Senate Transportation Committee on Feb. 6, saying the report documents which states require inspections and how often.

Adeline Collin, one of the report authors, told the committee the study reviewed statutes, administrative rules and state agency websites for all 50 states and recorded whether inspections were annual or biennial, applied statewide or by county, and whether states required safety checks, emissions testing, both or neither. “Our research focused strictly on what each state requires,” Collin said, and she noted the report was completed Nov. 19, 2025, before the 2026 legislative session.

The report’s headline findings, presented by Rhiannon Hubbard, show that 17 states require routine passenger-vehicle safety inspections and that 27 states have vehicle emissions testing requirements. Of the states with emissions testing, the presenters said 10 require testing annually and 15 require it biennially; presenters also said eight states with safety inspections use a biennial cadence. Hubbard noted that many states limit emissions testing to particular counties or metropolitan areas and that some states vary testing frequency by vehicle model year or county of registration.

The presenters cited Colorado and New Hampshire as examples of states with location- or model-year-based variations in testing, and said parts of the New England region have relatively stringent inspection rules. The students noted that much emissions-testing legislation traces to the federal Clean Air Act of 1990. The presenters also said five states have removed inspection laws since around 2000 and that 10 states currently have no statutory safety or emissions inspection requirements.

Committee members asked whether states that now use biennial testing had previously required annual testing and whether any states recently added safety-inspection mandates. The presenters said their review focused on statutory requirements and did not systematically track historical changes for each state but offered to follow up with additional research. Committee members also asked whether the report examined crash data to evaluate whether inspections affect vehicle safety; the presenters said they did not analyze crash statistics for this report but would look into it if the committee wanted that information.

The committee thanked the researchers and asked staff to coordinate any follow-up distribution to the chair. No committee action or vote was taken at the hearing.