In a surprising development, Arizona's proposed one percent hike in the state sales tax rate was kept off the November ballot after falling short of the number of valid signatures needed. The secretary of state found that a startling 47% of submitted signatures were invalid -- a finding the state's Supreme Court recently upheld.
Though Arizonans undoubtedly would have benefited from the influx of transportation dollars that this measure could have provided, the sales tax is arguably the worst method possible for funding transportation. Two competing principles exist for evaluating any tax proposal: the "ability-to-pay principle" and the "benefits principle". Even if you're unfamiliar with these principles by name, it's not at all difficult to see how the sales tax fails them both.
Under the "ability-to-pay principle", those best able to afford to pay for government should be asked to contribute the most. This is the standard by which most taxes are judged. Progressive income taxes that ask the most of society's wealthiest members fulfill this principle, while inherently regressive sales taxes do not.
In contrast, under the "benefits principle", taxes should be paid by those individuals who receive the benefits the government provides. In the realm of transportation, multiple options exist for fulfilling this principle, including the gas tax, tolls, vehicle sales taxes, registration/license fees, and in some cases even property taxes. The sales tax is only loosely (if at all) related to how much one benefits from the transportation infrastructure, and thus fails this principle as well.
Many (perhaps most) in the policy community believe the "benefits principle" to be the proper standard for judging transportation finance measures. But even if they're wrong, the fact that the sales tax fails both of the above mentioned principles means there is little or no reason to support such a measure.
Unfortunately, the attractiveness of the sales tax in the eyes of many lawmakers has grown as states seek to fill transportation funding shortfalls with anything but an increase in the gas tax. For example, a Minnesota bill that passed earlier this year allowed for several counties to raise their sales taxes for transportation. A Los Angeles transportation-related sales tax hike appears close to the ballot. Finally, numerous sales tax ideas have been floated in Virginia as a way of plugging a massive transportation funding shortfall. More state and local governments can be expected to follow this trend soon if gas tax revenues don't rebound.