A tax on vehicle miles traveled (VMT) was shot down last year by President Obama. But a new study by respected transportation experts – and a successful pilot program in Oregon – should revive the idea.As more Americans buy hybrid or electric cars, drivers in traditional gas-only vehicles are bound to start asking: Why should I still be paying more in fuel taxes? Don’t we all use the highways?Indeed, the gas tax is quickly becoming an unjust way to finance the costs of roads and bridges. All vehicles, whether they be a Hummer or a Prius, use the same infrastructure,...