Expert Urges House Transportation to Remove MIL/OBD-II Diagnostic from Annual Inspection and Expand Study of S.123

John Clifford, a retired automotive professor and former certified master ASC technician, told the Vermont House Committee on Transportation on May 7 that the portion of S.123 addressing the malfunction indicator lamp (MIL) and OBD‑II diagnostics should be removed from the state’s periodic vehicle inspection requirements and studied more comprehensively.

Clifford told lawmakers the OBD‑II diagnostic system — the onboard computer checks commonly reported to drivers as a “check engine” light or other diagnostic warning — requires specialized training and equipment that, he said, many inspection stations and motorists lack. "Diagnosing a mill light should not be in the province of periodic vehicle annual inspections, governing, controlled by the state," Clifford said, adding that in his view the diagnostic and repair work belongs to certified professionals.

The recommendation comes amid committee consideration of S.123, described at the hearing as a miscellaneous motor-vehicle bill containing a Section 43 provision addressing MIL/OBD‑II treatment in the inspection process. Clifford urged the committee to expand the study committee called for in the bill to examine the full inspection regime — including costs, effectiveness and possible tiered testing by vehicle age — and to drop the MIL requirement from annual inspections in the meantime.

Why it matters: Clifford told the committee that a 2024 DMV data point cited in testimony showed roughly 485,000 inspections and registrations; using a notional $100 inspection fee, he estimated the inspection process could represent about $50 million borne by motorists. He argued the public cost should be weighed against the safety benefits, noting he has seen serious defects during inspections but that state safety data cited in his remarks indicate less than 2% of traffic fatalities are attributed to defective vehicle parts or systems.

Clifford described the technical complexity behind modern vehicles and OBD‑II diagnostics: he said modern cars can have dozens of processors and multiplexed data buses, and that the OBD‑II diagnostic executive runs continuous tests that can flag intermittent faults such as misfires. He told the committee the OBD‑II standard was introduced in 1996 and that the inspection-related MIL checks are primarily a way to surface emissions- and safety-related faults for further diagnostic work.

On technician licensing and inspection practice, Clifford said Vermont lacks a broad licensing regime for general automotive technicians (he noted licensed emissions inspectors exist and that state inspector credentials are subject to renewal, which he recalled occurring each five years). He said some forms of OBD‑II and advanced diagnostics are resource-intensive for independent shops and can be expensive for motorists when a full diagnostic and repair is required. "A free code check is great, but I’m hoping no customer is gonna say, ‘Okay, what codes do I have stored and what am I now gonna change to fix my car?’" he said.

Committee members asked clarifying questions. Rep. White asked Clifford to define OBD; Clifford responded it stands for onboard diagnostics, second generation. Clifford also recommended the committee consider a tiered inspection approach based on vehicle age (for example, 0–10 years, 10–20 years, older categories), and suggested that for many newer vehicles the bulk of an inspection is an electronic hookup rather than a detailed mechanical check.

Clifford acknowledged that inspections occasionally identify vehicles in immediately unsafe condition and said he has once called police to prevent a vehicle from leaving a lot. Still, he urged lawmakers to weigh the frequency of such severe defects against the overall cost to motorists. He also recommended improving the proposed study committee in S.123 to collect more granular DMV data (for example, what percentage of failures are driven by warning lights and how much repairs actually cost motorists).

The committee did not take formal action during the hearing. Committee leadership noted the DMV and other stakeholders were present in the room, and the chair left committee time open after the scheduled 9:30 a.m. block for further testimony and discussion.

Clifford’s full suggestions included: removing the MIL/OBD‑II diagnostic from the state periodic inspection; expanding the bill’s study committee to examine the inspection program’s goals, costs to motorists, and the diagnostic/repair pathway; and exploring a tiered inspection schedule by vehicle age. He also urged attention to technician education and certification standards if the committee expects inspections to include advanced diagnostics.

No vote or formal committee direction on S.123’s Section 43 was recorded during the transcripted portion of the hearing.