US Postal's policy struggle for clean alternative fuel

If any organization has the incentive and the scale to roll out a fleet of alternative vehicles, it should be the United States Postal Service (USPS).

The post office operates the largest civilian vehicle fleet in the world, with more than 210,000 vehicles travelling almost 1.3 billion miles a year.
Its struggles to find cost-effective alternatives, however, highlight the obstacles to rolling out alternative vehicle technologies across the United States.