Is the claim by California assembly member Carl DeMaio that the proposed mileage tax in California would cost a family with two cars close to $4200 each year factual?

1. Where the $4,200 figure comes from — political messaging, not a legislative cost table

The $4,200 number appears repeatedly in DeMaio’s public comments and on Reform California materials asserting that “when you add the new mileage tax to the existing gas tax and car tax, the typical two‑car family will end up paying more than $4,200 in taxes a year” ^{[1] [3]}, and local TV reporting quotes DeMaio making the same claim ^[2]. Those sources are explicitly oppositional and framed as advocacy against AB 1421 and local mileage pilots ^{[3] [4]}.

2. What independent reporting and technical materials say about likely per‑driver costs

More measured coverage and technical pages show much smaller per‑driver cost ranges: DeMaio himself has also been quoted giving per‑driver estimates of roughly $600–$900 per year assuming 15,000 miles ^{[5] [6]}, while local TV cited his estimate of $900–$1,200 per year for the average Californian under a road‑charge system ^[7]. The official California road charge materials describe the policy as an alternative mechanism to the gas tax — potentially a replacement rather than necessarily an addition — and do not present a statewide $4,200 family figure in the materials provided ^[8].

3. Key variables that make the $4,200 claim a stretch in most scenarios

Whether a two‑car household reaches $4,200 depends on stacking assumptions: the per‑mile charge level (DeMaio’s cited ranges vary from roughly 4–9 cents per mile in different venues) ^{[1] [6]}, whether the mileage fee would be charged in addition to existing gas and vehicle taxes (some pilots and analyses discussed it as an addition, which opponents highlighted) ^[9], miles driven per vehicle, and whether the road charge replaces or supplements fuel taxes ^{[8] [10]}. Using the higher per‑driver figures quoted ($900–$1,200), two drivers would pay about $1,800–$2,400 — materially less than $4,200 — unless additional taxes or unusually high per‑mile rates are assumed ^{[7] [5]}.

4. What AB 1421 actually does and why that matters for cost claims

AB 1421, as reported, extends the Road Usage Charge Technical Advisory Committee to research and recommend options rather than immediately imposing a statewide mileage tax; critics and supporters framed the bill differently, with Republicans opposing and proponents characterizing it as study and planning work ^{[2] [10]}. That means blanket cost declarations like $4,200 are predictive political claims rather than statutory arithmetic derived from enacted law in the sources available ^{[2] [10]}.

5. Competing narratives and the analytic gap

Opponents (including DeMaio and Reform California) present worst‑case additive math to energize voters and candidates ^{[3] [4]}, while some analysts and advocates argue a road charge should or could replace fuel taxes to avoid double taxation — a technical design choice highlighted by California road‑charge materials and transportation experts ^{[8] [9]}. The sources provided do not include an independent statewide fiscal projection that documents a typical two‑car family paying roughly $4,200 per year under a specific, final policy design; therefore the $4,200 claim remains an unverified advocacy figure in the reporting at hand ^{[1] [3] [2]}.

Bottom line

The claim that a two‑car family would pay “close to $4,200 each year” is traceable to Carl DeMaio and allied advocacy and relies on stacking high per‑mile estimates with existing taxes, but the more conservative per‑driver figures reported ($600–$1,200) imply much lower two‑car totals in typical scenarios; the reporting provided contains no independent calculation or enacted policy that confirms a $4,200‑per‑year reality ^{[1] [5] [7] [8] [2]}.