From flailing transit systems to inadequate maintenance, states throughout the country are struggling to adequately fund their transportation infrastructure. Making the problem more difficult is the fact that one of their primary funding mechanisms, the gas tax, is failing to cover added costs. Due to projected revenue decline from increased fuel efficiency and EVs, the political aversion to raising the tax, and looming fiscal cliffs, some state legislatures are beginning to consider how to supplement gas tax revenue to sustainably fund their transportations systems.