Arizona SCR 1004, transmitted from the 2025 legislative session for voter consideration, proposes a constitutional prohibition on state or local taxes or fees based on vehicle miles traveled. It would also prohibit laws or rules monitoring or limiting a person’s vehicle miles unless that person voluntarily consents, with exceptions including certain interstate commercial-vehicle fuel-tax or registration agreements. The proposal links two distinct issues—future road-funding mechanisms and privacy around travel data—into one constitutional rule. A mileage tax could someday replace declining fuel-tax revenue, but it can also require tracking information people reasonably consider private. Arizona should separate how roads are funded from how much travel data government is allowed to collect.