Lawmakers debate timing and design of proposed mileage-based user fee, flag potential constitutional and revenue issues

Members of the conference committee on H.488, the transportation bill, spent substantial time debating the proposed shift to a mileage-based user fee and related electric-vehicle (EV) charges, focusing on implementation dates, revenue timing and legal risks.

The committee was split on when to begin collections: the House language would start July 1, 2026, while the Senate would delay to Jan. 1, 2027, creating roughly a six-month lead-time difference for agency implementation. Damien Leonard, legislative counsel, said the Senate wanted more cushion for rulemaking and program setup, while the House had expected an earlier start tied to prior appropriations support.

Why it matters: timing affects expected transportation revenue and program readiness. Committee members repeatedly noted that delays could reduce near-term transportation funds by millions of dollars and that implementation mechanics — how mileage will be measured, credited and coordinated with other potential EV charges — remain unresolved.

Key discussion points

- Start date and revenue: The House’s July 1, 2026 date would generate revenue sooner but could strain the Agency of Transportation’s (AOT) ability to implement systems on the House timeline; the Senate’s Jan. 1, 2027 date is intended to allow additional implementation time. Lawmakers estimated the delay could represent several million dollars of foregone revenue in the interim.

- Legislative control of rates: Conferees emphasized that the legislature, not AOT, will set any final fee amount before collections begin. Committee members reiterated that enabling language must preserve legislative authority to adopt rates and guardrails.

- Out-of-state EVs and constitutional concerns: Conferees discussed whether a mileage-based program or a separate EV charging surcharge could be structured to recoup lost fuel-tax revenue from out-of-state plug-in vehicles without running afoul of constitutional limits on discriminating against interstate commerce. Leonard warned that targeting out‑of‑state EV travel could raise constitutional flags and must be carefully structured.

- Alternatives and equity: Several members urged caution about using mileage as a proxy for environmental policy. Some argued mileage charges measure road wear and usage (an equity with gas tax), while others said they penalize travel activity rather than vehicle efficiency; lawmakers noted vehicle weight is also a factor in road impacts.

What the committee directed

No formal votes were taken in the session excerpted. Members asked AOT, DMV and other stakeholders for implementation briefings on system design and enforcement, requested clearer fiscal estimates of revenue timing and impacts, and agreed to continue negotiating language in conference to preserve legislative control of fee-setting.

Ending

Conferees did not resolve the differences during the session. The committee signaled continued work in conference to reconcile implementation timing, revenue assumptions and the legal structure to capture EV-related revenue without exceeding statutory or constitutional authority.