"USPS is expected to provide prompt, reliable and efficient nationwide servicewhile remaining self-supporting, but itis facing serious fiscal challenges withinsufficient revenues to cover itsexpenses. Mail delivery is USPS'slargest cost area, totaling about $30billion annually. Although USPS lacksauthority to make certain changes thatcould reduce costs, it does have theauthority to convert from moreexpensive to less expensive deliverymodes.GAO was asked to examine potentialcost savings and issues related todelivery conversion. This reportdiscusses: (1) the estimated costs ofeach delivery mode and potentialsavings associated with converting toless costly modes and (2) USPSactions to convert to less costlydelivery modes and any impedimentsto conversions. GAO obtained andanalyzed USPS estimates from fiscalyears 1994 through 2012 on deliverymode costs as well as potentialsavings from conversions to less costlymodes and determined that theestimates have limitations, which wediscuss in the report. GAO alsointerviewed officials from USPS andmailing industry stakeholders."