The idea rests on the simple fact that heavier vehicles impose more road strain and cause more repair needs than lighter ones. The Times suggests that a fee structure could be set up so that the typical American driver pays about $50 a year for their ton-mile fees, a small amount that would eliminate the budget shortfall. Plug-in vehicles that currently pay little or no refueling taxes would have to pay their share, and a weight-based fee structure could help encourage people to drive smaller cars (any link between this writer's inability to poke holes in this plan and his ownership of a Mini is purely coincidental).
New ideas are needed because improving fleetwide fuel economy means less fees are collected per mile driven. Recently, a Democratic representative from Oregon proposed to the House that federal gas taxes be almost doubled to 33.4 cents per gallon of gasoline, up from 18.4. States tack on another 31.1 cents a gallon, on average, but that's proving to not be enough. Read the op-ed here for the full details.