In light of higher gas prices, and so much public concern about environmental issues, I got to wondering: why does the US Postal Service deliver on Saturdays? Most non-retail businesses - and government agencies - operate primarily on a Monday through Friday schedule. So why does the USPS continue working on Saturday? It strikes me that discontinuing Saturday service would be a huge public-relations coup. And as much as I hate environmentalism and eco-religion, strictly from an economic perspective, the amount of gas that would be saved from such a move would be enormous

So. Anyone know why the USPS delivers on Saturday?